JAVA高级面试进阶训练营视频教程

admin · 发表于 2021-7-9 11:44:45

一、统一处理返回结果和异常处理的原因：

1、在springboot项目里我们希望接口返回的数据包含至少三个属性：

a、code：请求接口的返回码，成功或者异常等返回编码，例如定义请求成功，code = "0000",查询结果为null，code = "0001";

b、msg：请求接口的描述，也就是对返回编码的描述，"0000"：就表示请求成功，"0001"：表示结果为null；

c、data：请求接口成功，返回的结果。


   
    
     
      
       
      
      
      
        { 
       
      
     
      
       
      
      
       
       "data": { 
       
      
     
      
       
      
      
       
       "id": 
       1, 
       
      
     
      
       
      
      
       
       "studentId": 
       "13240115", 
       
      
     
      
       
      
      
       
       "name": 
       "Tiger", 
       
      
     
      
       
      
      
       
       "age": 
       25, 
       
      
     
      
       
      
      
       
       "famillyAddress": 
       "北京", 
       
      
     
      
       
      
      
       
       "createdDate": 
       "2018-10-08T05:45:49.000+0000", 
       
      
     
      
       
      
      
       
       "updatedDate": 
       "2018-10-09T03:15:33.000+0000" 
       
      
     
      
       
      
      
      
        }, 
       
      
     
      
       
      
      
       
       "code": 
       "0000", 
       
      
     
      
       
      
      
       
       "msg": 
       "请求成功" 
       
      
     
      
       
      
      
      
        }

2、在springboot项目里我们希望请求结果失败之后，通过返回码和返回描述来告诉前端接口请求异常。

二、案例

1、建一张学生信息表，包含学生的学号、姓名、年龄、家庭住址等


   
    
     
      
       
      
      
       
       CREATE 
       TABLE student_info ( 
       
      
     
      
       
      
      
       
       id 
       bigint( 
       20) 
       NOT 
       NULL AUTO_INCREMENT 
       COMMENT 
       '自增', 
       
      
     
      
       
      
      
      
        student_id 
       varchar( 
       20) 
       NOT 
       NULL 
       COMMENT 
       '学号', 
       
      
     
      
       
      
      
       
       name 
       varchar( 
       64) 
       NOT 
       NULL 
       COMMENT 
       '姓名', 
       
      
     
      
       
      
      
      
        age 
       int( 
       2) 
       NOT 
       NULL 
       COMMENT 
       '年龄', 
       
      
     
      
       
      
      
      
        familly_address 
       varchar( 
       256) 
       NOT 
       NULL 
       COMMENT 
       '家庭地址', 
       
      
     
      
       
      
      
      
        created_date datetime 
       NOT 
       NULL 
       DEFAULT 
       CURRENT_TIMESTAMP 
       COMMENT 
       '创建时间', 
       
      
     
      
       
      
      
      
        updated_date datetime 
       NOT 
       NULL 
       DEFAULT 
       CURRENT_TIMESTAMP 
       COMMENT 
       '更新时间', 
       
      
     
      
       
      
      
      
        PRIMARY 
       KEY (student_id), 
       
      
     
      
       
      
      
       
       KEY 
       id ( 
       id) 
       
      
     
      
       
      
      
      
        ) 
       ENGINE= 
       InnoDB 
       DEFAULT 
       CHARSET=utf8mb4

2、pom.xml


   
    
     
      
       
      
      
       
       <dependencies> 
       
      
     
      
       
      
      
       
       <dependency> 
       
      
     
      
       
      
      
       
       <groupId>org.springframework.boot 
       </groupId> 
       
      
     
      
       
      
      
       
       <artifactId>spring-boot-starter-web 
       </artifactId> 
       
      
     
      
       
      
      
       
       </dependency> 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       <dependency> 
       
      
     
      
       
      
      
       
       <groupId>org.springframework.boot 
       </groupId> 
       
      
     
      
       
      
      
       
       <artifactId>spring-boot-starter-test 
       </artifactId> 
       
      
     
      
       
      
      
       
       <scope>test 
       </scope> 
       
      
     
      
       
      
      
       
       </dependency> 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       <dependency> 
       
      
     
      
       
      
      
       
       <groupId>org.springframework.boot 
       </groupId> 
       
      
     
      
       
      
      
       
       <artifactId>spring-boot-starter-data-redis 
       </artifactId> 
       
      
     
      
       
      
      
       
       </dependency> 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       <dependency> 
       
      
     
      
       
      
      
       
       <groupId>org.mybatis.spring.boot 
       </groupId> 
       
      
     
      
       
      
      
       
       <artifactId>mybatis-spring-boot-starter 
       </artifactId> 
       
      
     
      
       
      
      
       
       <version>1.3.1 
       </version> 
       
      
     
      
       
      
      
       
       </dependency> 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       <dependency> 
       
      
     
      
       
      
      
       
       <groupId>mysql 
       </groupId> 
       
      
     
      
       
      
      
       
       <artifactId>mysql-connector-java 
       </artifactId> 
       
      
     
      
       
      
      
       
       <version>5.1.46 
       </version> 
       
      
     
      
       
      
      
       
       </dependency> 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       <dependency> 
       
      
     
      
       
      
      
       
       <groupId>com.alibaba 
       </groupId> 
       
      
     
      
       
      
      
       
       <artifactId>druid 
       </artifactId> 
       
      
     
      
       
      
      
       
       <version>1.1.9 
       </version> 
       
      
     
      
       
      
      
       
       </dependency> 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       <dependency> 
       
      
     
      
       
      
      
       
       <groupId>org.projectlombok 
       </groupId> 
       
      
     
      
       
      
      
       
       <artifactId>lombok 
       </artifactId> 
       
      
     
      
       
      
      
       
       <version>1.16.22 
       </version> 
       
      
     
      
       
      
      
       
       </dependency> 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       <dependency> 
       
      
     
      
       
      
      
       
       <groupId>com.alibaba 
       </groupId> 
       
      
     
      
       
      
      
       
       <artifactId>fastjson 
       </artifactId> 
       
      
     
      
       
      
      
       
       <version>1.2.43 
       </version> 
       
      
     
      
       
      
      
       
       </dependency> 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       <dependency> 
       
      
     
      
       
      
      
       
       <groupId>com.squareup.okhttp3 
       </groupId> 
       
      
     
      
       
      
      
       
       <artifactId>okhttp 
       </artifactId> 
       
      
     
      
       
      
      
       
       <version>3.9.1 
       </version> 
       
      
     
      
       
      
      
       
       </dependency> 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       <dependency> 
       
      
     
      
       
      
      
       
       <groupId>org.glassfish 
       </groupId> 
       
      
     
      
       
      
      
       
       <artifactId>javax.json 
       </artifactId> 
       
      
     
      
       
      
      
       
       <version>1.0.4 
       </version> 
       
      
     
      
       
      
      
       
       </dependency> 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       <dependency> 
       
      
     
      
       
      
      
       
       <groupId>org.apache.tomcat.embed 
       </groupId> 
       
      
     
      
       
      
      
       
       <artifactId>tomcat-embed-jasper 
       </artifactId> 
       
      
     
      
       
      
      
       
       </dependency> 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       </dependencies>

3、案例中使用redis进行缓存，可以不需要

Windows环境安装redis以及缓存应用

4、创建实体类：StudentInfo


   
    
     
      
       
      
      
       
       package com.dl.cn.message.bean; 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       import lombok.AllArgsConstructor; 
       
      
     
      
       
      
      
       
       import lombok.Builder; 
       
      
     
      
       
      
      
       
       import lombok.Data; 
       
      
     
      
       
      
      
       
       import lombok.NoArgsConstructor; 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       import java.io.Serializable; 
       
      
     
      
       
      
      
       
       import java.util.Date; 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       /** 
       
      
     
      
       
      
      
       
        * Created by Tiger on 2018/10/8. 
       
      
     
      
       
      
      
       
        */ 
       
      
     
      
       
      
      
       
       @Data 
       
      
     
      
       
      
      
       
       @Builder 
       
      
     
      
       
      
      
       
       @AllArgsConstructor 
       
      
     
      
       
      
      
       
       @NoArgsConstructor 
       
      
     
      
       
      
      
       
       public 
       class StudentInfo implements Serializable{ 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       private 
       static 
       final 
       long serialVersionUID = 
       2597547944454691103L; 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       private Long id; 
       
      
     
      
       
      
      
       
       private String studentId; 
       
      
     
      
       
      
      
       
       private String name; 
       
      
     
      
       
      
      
       
       private Integer age; 
       
      
     
      
       
      
      
       
       private String famillyAddress; 
       
      
     
      
       
      
      
       
       private Date createdDate; 
       
      
     
      
       
      
      
       
       private Date updatedDate; 
       
      
     
      
       
      
      
      
        }

5、创建Mapper：StudentInfoMapper


   
    
     
      
       
      
      
       
       package com.dl.cn.message.mapper; 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       import com.dl.cn.message.bean.StudentInfo; 
       
      
     
      
       
      
      
       
       import org.apache.ibatis.annotations.*; 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       /** 
       
      
     
      
       
      
      
       
        * Created by Tiger on 2018/10/8. 
       
      
     
      
       
      
      
       
        */ 
       
      
     
      
       
      
      
       
       @Mapper 
       
      
     
      
       
      
      
       
       public 
       interface StudentInfoMapper { 
       
      
     
      
       
      
      
       
       @Insert("insert into student_info(student_id,name,age,familly_address)" + 
       
      
     
      
       
      
      
       
       " values(#{studentId},#{name},#{age},#{famillyAddress})") 
       
      
     
      
       
      
      
       
       /** 
       
      
     
      
       
      
      
       
        * 通过bean保存实体类是，建议不要通过@Param注解，负责实体类的属性都在@Param中找 
       
      
     
      
       
      
      
       
        * */ 
       
      
     
      
       
      
      
      
        void saveStudentInfo(StudentInfo studentInfo); 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       @Select("select * from student_info where student_id = #{studentId}") 
       
      
     
      
       
      
      
      
        StudentInfo findByStudentId( 
       @Param("studentId") String studentId); 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       @Update("update student_info set familly_address = #{famillyAddress},updated_date = now() ") 
       
      
     
      
       
      
      
      
        void updateFamillyAddress( 
       @Param("studentId") String studentId, 
       @Param("famillyAddress") String famillyAddress); 
       
      
     
      
       
      
      
      
        }

6、创建service：StudentInfoService


   
    
     
      
       
      
      
       
       package com.dl.cn.message.service; 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       import com.dl.cn.message.bean.StudentInfo; 
       
      
     
      
       
      
      
       
       import com.dl.cn.message.mapper.StudentInfoMapper; 
       
      
     
      
       
      
      
       
       import lombok.extern.slf4j.Slf4j; 
       
      
     
      
       
      
      
       
       import org.springframework.beans.factory. 
       annotation.Autowired; 
       
      
     
      
       
      
      
       
       import org.springframework.cache. 
       annotation.CacheConfig; 
       
      
     
      
       
      
      
       
       import org.springframework.cache. 
       annotation.CacheEvict; 
       
      
     
      
       
      
      
       
       import org.springframework.cache. 
       annotation.Cacheable; 
       
      
     
      
       
      
      
       
       import org.springframework.stereotype.Service; 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       /** 
       
      
     
      
       
      
      
       
        * Created by Tiger on 2018/10/8. 
       
      
     
      
       
      
      
       
        */ 
       
      
     
      
       
      
      
       
       @Service 
       
      
     
      
       
      
      
       
       @CacheConfig(cacheNames = "studentInfo") 
       
      
     
      
       
      
      
       
       @Slf4j 
       
      
     
      
       
      
      
       
       public 
       class StudentInfoService { 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       @Autowired 
       
      
     
      
       
      
      
      
        StudentInfoMapper studentInfoMapper; 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       /** 
       
      
     
      
       
      
      
       
        * 保存学生信息 
       
      
     
      
       
      
      
       
        * @param studentInfo 
       
      
     
      
       
      
      
       
        * */ 
       
      
     
      
       
      
      
       
       public void saveStudentInfo(StudentInfo studentInfo){ 
       
      
     
      
       
      
      
      
        studentInfoMapper.saveStudentInfo(studentInfo); 
       
      
     
      
       
      
      
      
        } 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       /** 
       
      
     
      
       
      
      
       
        * 根据学号查学生信息 
       
      
     
      
       
      
      
       
        * @param studentId 
       
      
     
      
       
      
      
       
        * @return 
       
      
     
      
       
      
      
       
        * */ 
       
      
     
      
       
      
      
       
       @Cacheable(key = "#studentId",unless = "#result == null") 
       
      
     
      
       
      
      
       
       public StudentInfo findByStudentId(String studentId){ 
       
      
     
      
       
      
      
      
        log.info( 
       "查找信息:{}",studentId); 
       
      
     
      
       
      
      
       
       return studentInfoMapper.findByStudentId(studentId); 
       
      
     
      
       
      
      
      
        } 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       /** 
       
      
     
      
       
      
      
       
        * 根据学号更新家庭地址 
       
      
     
      
       
      
      
       
        * @param studentId 
       
      
     
      
       
      
      
       
        * @param famillyAddress 
       
      
     
      
       
      
      
       
        * */ 
       
      
     
      
       
      
      
       
       //删除对应key的缓存 
       
      
     
      
       
      
      
       
       @CacheEvict(key = "#studentId") 
       
      
     
      
       
      
      
       
       public void updateFamillyAddress(String studentId,String famillyAddress){ 
       
      
     
      
       
      
      
      
        studentInfoMapper.updateFamillyAddress(studentId,famillyAddress); 
       
      
     
      
       
      
      
      
        } 
       
      
     
      
       
      
      
      
        }

7、创建统一返回结果类：Response


   
    
     
      
       
      
      
       
       package com.dl.cn.message.response; 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       import com.fasterxml.jackson.databind. 
       annotation.JsonSerialize; 
       
      
     
      
       
      
      
       
       import lombok.Getter; 
       
      
     
      
       
      
      
       
       import lombok.Setter; 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       import java.io.Serializable; 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       /** 
       
      
     
      
       
      
      
       
        * 请求返回类 
       
      
     
      
       
      
      
       
        * Created by Tiger on 2018/10/9. 
       
      
     
      
       
      
      
       
        */ 
       
      
     
      
       
      
      
       
       @Getter 
       
      
     
      
       
      
      
       
       @Setter 
       
      
     
      
       
      
      
       
       @JsonSerialize(include= JsonSerialize.Inclusion.NON_NULL) 
       
      
     
      
       
      
      
       
       public 
       class Response<T> implements Serializable { 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       private static 
       final long serialVersionUID = 
       -4505655308965878999L; 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       //请求成功返回码为：0000 
       
      
     
      
       
      
      
       
       private static 
       final String successCode = 
       "0000"; 
       
      
     
      
       
      
      
       
       //返回数据 
       
      
     
      
       
      
      
       
       private T 
       data; 
       
      
     
      
       
      
      
       
       //返回码 
       
      
     
      
       
      
      
       
       private String code; 
       
      
     
      
       
      
      
       
       //返回描述 
       
      
     
      
       
      
      
       
       private String msg; 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       public Response(){ 
       
      
     
      
       
      
      
       
       this.code = successCode; 
       
      
     
      
       
      
      
       
       this.msg = 
       "请求成功"; 
       
      
     
      
       
      
      
      
        } 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       public Response(String code,String msg){ 
       
      
     
      
       
      
      
       
       this(); 
       
      
     
      
       
      
      
       
       this.code = code; 
       
      
     
      
       
      
      
       
       this.msg = msg; 
       
      
     
      
       
      
      
      
        } 
       
      
     
      
       
      
      
       
       public Response(String code,String msg,T 
       data){ 
       
      
     
      
       
      
      
       
       this(); 
       
      
     
      
       
      
      
       
       this.code = code; 
       
      
     
      
       
      
      
       
       this.msg = msg; 
       
      
     
      
       
      
      
       
       this. 
       data = 
       data; 
       
      
     
      
       
      
      
      
        } 
       
      
     
      
       
      
      
       
       public Response(T 
       data){ 
       
      
     
      
       
      
      
       
       this(); 
       
      
     
      
       
      
      
       
       this. 
       data = 
       data; 
       
      
     
      
       
      
      
      
        } 
       
      
     
      
       
      
      
      
        }

8、创建异常编码和描述类：ErrorCodeAndMsg


   
    
     
      
       
      
      
       
       package com.dl.cn.message.enums; 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       /** 
       
      
     
      
       
      
      
       
        * Created by Tiger on 2018/10/9. 
       
      
     
      
       
      
      
       
        */ 
       
      
     
      
       
      
      
       
       public 
       enum ErrorCodeAndMsg { 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
      
        Student_number_does_not_exist( 
       "0001", 
       "学号不存在"), 
       
      
     
      
       
      
      
      
        Insufficient_student_number( 
       "0002", 
       "学号长度不足"), 
       
      
     
      
       
      
      
      
        Student_number_is_empty( 
       "0003", 
       "学号为空"), 
       
      
     
      
       
      
      
      
        Network_error( 
       "9999", 
       "网络错误，待会重试"), 
       
      
     
      
       
      
      
      
        ; 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       private String code; 
       
      
     
      
       
      
      
       
       private String msg; 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
      
        ErrorCodeAndMsg(String code, String msg) { 
       
      
     
      
       
      
      
       
       this.code = code; 
       
      
     
      
       
      
      
       
       this.msg = msg; 
       
      
     
      
       
      
      
      
        } 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       public String getCode() { 
       
      
     
      
       
      
      
       
       return code; 
       
      
     
      
       
      
      
      
        } 
       
      
     
      
       
      
      
       
       public void setCode(String code) { 
       
      
     
      
       
      
      
       
       this.code = code; 
       
      
     
      
       
      
      
      
        } 
       
      
     
      
       
      
      
       
       public String getMsg() { 
       
      
     
      
       
      
      
       
       return msg; 
       
      
     
      
       
      
      
      
        } 
       
      
     
      
       
      
      
       
       public void setMsg(String msg) { 
       
      
     
      
       
      
      
       
       this.msg = msg; 
       
      
     
      
       
      
      
      
        } 
       
      
     
      
       
      
      
      
        }

9、创建统一异常处理类：StudentException


   
    
     
      
       
      
      
       
       package com.dl.cn.message.exception; 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       import com.dl.cn.message.enums.ErrorCodeAndMsg; 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       import java.io.Serializable; 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       /** 
       
      
     
      
       
      
      
       
        * 统一异常捕获类 
       
      
     
      
       
      
      
       
        * Created by Tiger on 2018/10/9. 
       
      
     
      
       
      
      
       
        */ 
       
      
     
      
       
      
      
       
       public 
       class StudentException extends RuntimeException{ 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       private 
       static 
       final 
       long serialVersionUID = - 
       6370612186038915645L; 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       private 
       final ErrorCodeAndMsg response; 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       public StudentException(ErrorCodeAndMsg response) { 
       
      
     
      
       
      
      
       
       this.response = response; 
       
      
     
      
       
      
      
      
        } 
       
      
     
      
       
      
      
       
       public ErrorCodeAndMsg getResponse() { 
       
      
     
      
       
      
      
       
       return response; 
       
      
     
      
       
      
      
      
        } 
       
      
     
      
       
      
      
      
        }

10、创建异常处理的全局配置类：ExceptionHandler


   
    
     
      
       
      
      
      
        package com.dl.cn.message.exception; 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
      
        import com.dl.cn.message.enums.ErrorCodeAndMsg; 
       
      
     
      
       
      
      
      
        import com.dl.cn.message. 
       response. 
       Response; 
       
      
     
      
       
      
      
      
        import lombok.extern.slf4j.Slf4j; 
       
      
     
      
       
      
      
      
        import org.springframework.web.bind.annotation.ControllerAdvice; 
       
      
     
      
       
      
      
      
        import org.springframework.web.bind.annotation.ResponseBody; 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
      
        import javax.servlet.http.HttpServletRequest; 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
      
        /** 
       
      
     
      
       
      
      
      
        * Created by Tiger 
       on 
       2018/ 
       10/ 
       9. 
       
      
     
      
       
      
      
      
        */ 
       
      
     
      
       
      
      
      
        @ControllerAdvice 
       
      
     
      
       
      
      
      
        @Slf4j 
       
      
     
      
       
      
      
       
       public 
       class ExceptionHandler { 
       
      
     
      
       
      
      
      
        @org.springframework.web.bind.annotation.ExceptionHandler(StudentException. 
       class) 
       
      
     
      
       
      
      
      
        @ResponseBody 
       
      
     
      
       
      
      
       
       public 
       Response handleStudentException(HttpServletRequest 
       request, StudentException ex) { 
       
      
     
      
       
      
      
       
       Response 
       response; 
       
      
     
      
       
      
      
       
       log. 
       error( 
       "StudentException code:{},msg:{}",ex.getResponse().getCode(),ex.getResponse().getMsg()); 
       
      
     
      
       
      
      
       
       response = 
       new 
       Response(ex.getResponse().getCode(),ex.getResponse().getMsg()); 
       
      
     
      
       
      
      
      
        return 
       response; 
       
      
     
      
       
      
      
      
        } 
       
      
     
      
       
      
      
      
        @org.springframework.web.bind.annotation.ExceptionHandler(Exception. 
       class) 
       
      
     
      
       
      
      
      
        @ResponseBody 
       
      
     
      
       
      
      
       
       public 
       Response handleException(HttpServletRequest 
       request, Exception ex) { 
       
      
     
      
       
      
      
       
       Response 
       response; 
       
      
     
      
       
      
      
       
       log. 
       error( 
       "exception error:{}",ex); 
       
      
     
      
       
      
      
       
       response = 
       new 
       Response(ErrorCodeAndMsg.Network_error.getCode(), 
       
      
     
      
       
      
      
      
        ErrorCodeAndMsg.Network_error.getMsg()); 
       
      
     
      
       
      
      
      
        return 
       response; 
       
      
     
      
       
      
      
      
        } 
       
      
     
      
       
      
      
      
        }

11、创建controler类：StudentInofController


   
    
     
      
       
      
      
       
       package com.dl.cn.message.controller; 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       import com.dl.cn.message.enums.ErrorCodeAndMsg; 
       
      
     
      
       
      
      
       
       import com.dl.cn.message.exception.StudentException; 
       
      
     
      
       
      
      
       
       import com.dl.cn.message.response.Response; 
       
      
     
      
       
      
      
       
       import com.dl.cn.message.service.StudentInfoService; 
       
      
     
      
       
      
      
       
       import com.dl.cn.message.bean.StudentInfo; 
       
      
     
      
       
      
      
       
       import lombok.extern.slf4j.Slf4j; 
       
      
     
      
       
      
      
       
       import org.springframework.beans.factory. 
       annotation.Autowired; 
       
      
     
      
       
      
      
       
       import org.springframework.web.bind. 
       annotation.PostMapping; 
       
      
     
      
       
      
      
       
       import org.springframework.web.bind. 
       annotation.RequestMapping; 
       
      
     
      
       
      
      
       
       import org.springframework.web.bind. 
       annotation.RequestParam; 
       
      
     
      
       
      
      
       
       import org.springframework.web.bind. 
       annotation.RestController; 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       /** 
       
      
     
      
       
      
      
       
        * Created by Tiger on 2018/10/8. 
       
      
     
      
       
      
      
       
        */ 
       
      
     
      
       
      
      
       
       @RestController 
       
      
     
      
       
      
      
       
       @RequestMapping("/student") 
       
      
     
      
       
      
      
       
       @Slf4j 
       
      
     
      
       
      
      
       
       public 
       class StudentInofController { 
       
      
     
      
       
      
      
       
       @Autowired 
       
      
     
      
       
      
      
      
        StudentInfoService studentInfoService; 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       /** 
       
      
     
      
       
      
      
       
        * 保存学生信息 
       
      
     
      
       
      
      
       
        * @param studentId 
       
      
     
      
       
      
      
       
        * @param name 
       
      
     
      
       
      
      
       
        * @param age 
       
      
     
      
       
      
      
       
        * @param famillyAddress 
       
      
     
      
       
      
      
       
        * */ 
       
      
     
      
       
      
      
       
       @PostMapping("/save") 
       
      
     
      
       
      
      
       
       public void saveStudentInfo( 
       @RequestParam("student_id") String studentId, 
       
      
     
      
       
      
      
       
       @RequestParam("name") String name, 
       
      
     
      
       
      
      
       
       @RequestParam("age") Integer age, 
       
      
     
      
       
      
      
       
       @RequestParam("familly_address") String famillyAddress){ 
       
      
     
      
       
      
      
      
        StudentInfo studentInfo = StudentInfo.builder() 
       
      
     
      
       
      
      
      
        .studentId(studentId) 
       
      
     
      
       
      
      
      
        .name(name) 
       
      
     
      
       
      
      
      
        .age(age) 
       
      
     
      
       
      
      
      
        .famillyAddress(famillyAddress) 
       
      
     
      
       
      
      
      
        .build(); 
       
      
     
      
       
      
      
      
        studentInfoService.saveStudentInfo(studentInfo); 
       
      
     
      
       
      
      
      
        } 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       /** 
       
      
     
      
       
      
      
       
        * 根据学号查学生信息 
       
      
     
      
       
      
      
       
        * @param studentId 
       
      
     
      
       
      
      
       
        * @return 
       
      
     
      
       
      
      
       
        * */ 
       
      
     
      
       
      
      
       
       @PostMapping("/findByStudentId") 
       
      
     
      
       
      
      
       
       public Response findByStudentId( 
       @RequestParam("student_id") String studentId){ 
       
      
     
      
       
      
      
       
       try{ 
       
      
     
      
       
      
      
      
        log.info( 
       "Get student information based on student number:{}",studentId); 
       
      
     
      
       
      
      
       
       if(studentId == 
       null){ 
       
      
     
      
       
      
      
       
       throw new StudentException(ErrorCodeAndMsg.Student_number_is_empty); 
       
      
     
      
       
      
      
      
        } 
       
      
     
      
       
      
      
       
       //学号固定为8位 
       
      
     
      
       
      
      
       
       if(studentId.length() != 
       8){ 
       
      
     
      
       
      
      
       
       throw new StudentException(ErrorCodeAndMsg.Insufficient_student_number); 
       
      
     
      
       
      
      
      
        } 
       
      
     
      
       
      
      
      
        StudentInfo studentInfo = studentInfoService.findByStudentId(studentId); 
       
      
     
      
       
      
      
       
       if(studentInfo == 
       null){ 
       
      
     
      
       
      
      
       
       throw new StudentException(ErrorCodeAndMsg.Student_number_does_not_exist); 
       
      
     
      
       
      
      
      
        } 
       
      
     
      
       
      
      
       
       return new Response(studentInfo); 
       
      
     
      
       
      
      
      
        } 
       catch (Exception e){ 
       
      
     
      
       
      
      
       
       if(e instanceof StudentException){ 
       
      
     
      
       
      
      
       
       throw e; 
       
      
     
      
       
      
      
      
        } 
       else { 
       
      
     
      
       
      
      
      
        log.error( 
       "findByStudentId error:",e); 
       
      
     
      
       
      
      
       
       throw new StudentException(ErrorCodeAndMsg.Network_error); 
       
      
     
      
       
      
      
      
        } 
       
      
     
      
       
      
      
      
        } 
       
      
     
      
       
      
      
      
        } 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       @PostMapping("/updateFamillyAddress") 
       
      
     
      
       
      
      
       
       public Response updateFamillyAddress( 
       @RequestParam("student_id") String studentId, 
       
      
     
      
       
      
      
       
       @RequestParam("familly_address") String famillyAddress){ 
       
      
     
      
       
      
      
      
        studentInfoService.updateFamillyAddress(studentId,famillyAddress); 
       
      
     
      
       
      
      
      
        Response response = new Response(); 
       
      
     
      
       
      
      
      
        System. 
       out.println(response.toString()); 
       
      
     
      
       
      
      
       
       return response; 
       
      
     
      
       
      
      
      
        } 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
      
        }

12、application.properties配置


   
    
     
      
       
      
      
       
       #redis 
       
      
     
      
       
      
      
      
        spring.redis.host= 
       127.0 
       .0 
       .1 
       
      
     
      
       
      
      
      
        spring.redis.port= 
       6379 
       
      
     
      
       
      
      
      
        spring.redis.password=tiger 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       #mybatis 
       
      
     
      
       
      
      
       
       #开启mybatis驼峰命名，这样可以将mysql中带有下划线的映射成驼峰命名的字段 
       
      
     
      
       
      
      
      
        mybatis.configuration.map-underscore-to-camel- 
       case= 
       true 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
       
       #datasource 
       
      
     
      
       
      
      
      
        spring.datasource.url=jdbc:mysql: 
       //127.0.0.1:3306/tiger?useUnicode=true&characterEncoding=UTF-8&zeroDateTimeBehavior=convertToNull&autoReconnect=true&generateSimpleParameterMetadata=true 
       
      
     
      
       
      
      
      
        spring.datasource.username=tiger 
       
      
     
      
       
      
      
      
        spring.datasource.password=tiger 
       
      
     
      
       
      
      
      
        spring.datasource.driver- 
       class-name=com.mysql.jdbc.Driver 
       
      
     
      
       
      
      
      
        spring.datasource.type=com.alibaba.druid.pool.DruidDataSource 
       
      
     
      
       
      
      
      
        spring.datasource.max-idle= 
       10 
       
      
     
      
       
      
      
      
        spring.datasource.max-wait= 
       60000 
       
      
     
      
       
      
      
      
        spring.datasource.min-idle= 
       5 
       
      
     
      
       
      
      
      
        spring.datasource.initial-size= 
       5 
       
      
     
      
       
      
      
      
        spring.datasource.validationQuery=select 
       'x'

三、说明

1、controller层使用注解@RestController，这样返回结果就是json格式，而@Controller返回结果是字符串

2、throw 异常

如果exception类型是自定义的异常StudentException，直接抛出，如果是其它异常统一抛出网络错误


   
    
     
      
       
      
      
       
       try{ 
       
      
     
      
       
      
      
       
       
      
     
      
       
      
      
      
        } 
       catch ( 
       Exception e){ 
       
      
     
      
       
      
      
       
       if(e 
       instanceof StudentException){ 
       
      
     
      
       
      
      
       
       throw e; 
       
      
     
      
       
      
      
      
        } 
       else { 
       
      
     
      
       
      
      
      
        log.error( 
       "findByStudentId error:",e); 
       
      
     
      
       
      
      
       
       throw 
       new StudentException(ErrorCodeAndMsg.Network_error); 
       
      
     
      
       
      
      
      
        } 
       
      
     
      
       
      
      
      
        }

3、在返回结果类添加了注解@JsonSerialize(include= JsonSerialize.Inclusion.NON_NULL)

是因为更新或者删除操作，一般没有返回值，我只需要知道是否更新成功或者删除成功就OK了，如果不加这个注解

我们返回的结果中data为null！！！

加上注解再更新数据，返回结果：

因此这个注解的作用就是：返回结果中有null值，干掉它！

四、测试结果

mysql数据库中有一条学号为13240115的数据：

1、student_id = "13240115"时


   
    
     
      
       
      
      
      
        { 
       
      
     
      
       
      
      
       
       "data": { 
       
      
     
      
       
      
      
       
       "id": 
       1, 
       
      
     
      
       
      
      
       
       "studentId": 
       "13240115", 
       
      
     
      
       
      
      
       
       "name": 
       "Tiger", 
       
      
     
      
       
      
      
       
       "age": 
       25, 
       
      
     
      
       
      
      
       
       "famillyAddress": 
       "北京", 
       
      
     
      
       
      
      
       
       "createdDate": 
       "2018-10-08T05:45:49.000+0000", 
       
      
     
      
       
      
      
       
       "updatedDate": 
       "2018-10-09T05:36:36.000+0000" 
       
      
     
      
       
      
      
      
        }, 
       
      
     
      
       
      
      
       
       "code": 
       "0000", 
       
      
     
      
       
      
      
       
       "msg": 
       "请求成功" 
       
      
     
      
       
      
      
      
        }

2、student_id = "13240114"时

3、student_id = "1324011"，不足8位时

4、student_id = "13240115"，然后在接口中加上一行代码，System.out.println(1/0);

返回结果：


   
    
     
      
       
      
      
      
        { 
       
      
     
      
       
      
      
       
       "code": 
       "9999", 
       
      
     
      
       
      
      
       
       "msg": 
       "网络错误，待会重试" 
       
      
     
      
       
      
      
      
        }

控制台日志：


   
    
     
      
       
      
      
      
        java.lang. 
       ArithmeticException: / by zero 
       
      
     
      
       
      
      
      
        at com.dl.cn.message.controller. 
       StudentInofController.findByStudentId( 
       StudentInofController.java: 
       54) ~[classes/:na] 
       
      
     
      
       
      
      
      
        at sun. 
       reflect. 
       NativeMethodAccessorImpl.invoke0( 
       Native 
       Method) ~[na: 
       1.8. 
       0_161] 
       
      
     
      
       
      
      
      
        at sun. 
       reflect. 
       NativeMethodAccessorImpl.invoke( 
       NativeMethodAccessorImpl.java: 
       62) ~[na: 
       1.8. 
       0_161] 
       
      
     
      
       
      
      
      
        at sun. 
       reflect. 
       DelegatingMethodAccessorImpl.invoke( 
       DelegatingMethodAccessorImpl.java: 
       43) ~[na: 
       1.8. 
       0_161] 
       
      
     
      
       
      
      
      
        at java.lang. 
       reflect. 
       Method.invoke( 
       Method.java: 
       498) ~[na: 
       1.8. 
       0_161] 
       
      
     
      
       
      
      
      
        at org.springframework.web.method.support. 
       InvocableHandlerMethod.doInvoke( 
       InvocableHandlerMethod.java: 
       209) [spring-web- 
       5.0. 
       8. 
       RELEASE.jar: 
       5.0. 
       8. 
       RELEASE] 
       
      
     
      
       
      
      
      
        at org.springframework.web.method.support. 
       InvocableHandlerMethod.invokeForRequest( 
       InvocableHandlerMethod.java: 
       136) [spring-web- 
       5.0. 
       8. 
       RELEASE.jar: 
       5.0. 
       8. 
       RELEASE]

通过测试，发现这个小案例满足刚开始我们提出的需求，一定还有很多其它问题，暂时没有发现，我会及时修改，不知道有人是否看我的博客？我只是想把自己的学习成果总结记录下来。人可以成长为芳草，也可以长成杂莠！！！

原文地址：https://blog.csdn.net/qq_31289187/article/details/82980714

		自动登录	找回密码
密码			立即注册

JAVA高级面试进阶训练营视频教程	Java架构师系统进阶VIP课程	分布式高可用全栈开发微服务教程	Go语言视频零基础入门到精通	Java架构师3期(课件+源码)
Java开发全终端实战租房项目视频教程	SpringBoot2.X入门到高级使用教程	大数据培训第六期全套视频教程	深度学习（CNN RNN GAN）算法原理	Java亿级流量电商系统视频教程
互联网架构师视频教程	年薪50万Spark2.0从入门到精通	年薪50万！人工智能学习路线教程	年薪50万大数据入门到精通学习路线	年薪50万机器学习入门到精通教程
仿小米商城类app和小程序视频教程	深度学习数据分析基础到实战	最新黑马javaEE2.1就业课程	从 0到JVM实战高手教程	MySQL入门到精通教程

JAVA高级面试进阶训练营视频教程

Java架构师系统进阶VIP课程

springboot2.0-统一处理返回结果和异常情况