JAVA高级面试进阶训练营视频教程

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　　最近在使用Hibernate开发项目，在写好hql语句，并初始化Query对象，执行Query.list()方法时，应用报IllegalArgumentException异常。经网上查询，现已经基本决定原因，是由于在利用hibernate逆向工程生成实体类和映射文件时，数据库字段的numeric类型被逆向成了java实体类中的Doubel类型，然后我觉得这里不应该用包装类，手贱就改成了基本数据类型double，这一改出了问题，数据库中字段的数据类型和java实体类中的属性类型对不上了，出现了IllegalArgumentException异常。解决方法当然是将double类型改回Double类型。我想，如果大家也有这个异常，基本可以断定是由于数据库中的字段的数据类型和java实体类中的属性类型不匹配造成的。

　　现在将我解决问题的过程给大家描述一下：

1：出问题的代码位置：Query.list()方法

public PageModel queryByPage(String where, int start, int limit) {

        StringBuffer hql = new StringBuffer("SELECT Object(o) FROM DsImageVideoData AS o WHERE 1=1");
        StringBuffer hql_count = new StringBuffer("SELECT Count(o) FROM DsImageVideoData AS o WHERE 1=1");


        Session session = hibernateTemplate.getSessionFactory().openSession();    //获得hibernate session对象
        Query query = session.createQuery(hql.toString());    // 获得对应hql语句的查询对象query
        Query query_count = session.createQuery(hql_count.toString()); // 获得对应hql_count语句的查询对象query
        
        int pageTmp = start;
        int switchPage = (pageTmp -1 ) * limit;
        query.setFirstResult(switchPage);
        query.setMaxResults(10);
        PageModel page = new PageModel();
        page.setPageNumber(start);
        page.setObjectsPerPage(limit);
        page.setFullListSize(Integer.valueOf(query_count.list().get(0).toString()));
        page.setData(query.list());    //query.list()作用是执行查询，出现异常
        return page;
    }

　　以上代码中的page.setData(query.list());出现异常。

2. 异常信息

 1 严重: Servlet.service() for servlet dispatcher threw exception
 2 java.lang.IllegalArgumentException
 3     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 4     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
 5     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
 6     at java.lang.reflect.Method.invoke(Method.java:606)
 7     at org.hibernate.property.BasicPropertyAccessor$BasicSetter.set(BasicPropertyAccessor.java:42)
 8     at org.hibernate.tuple.entity.AbstractEntityTuplizer.setPropertyValues(AbstractEntityTuplizer.java:337)
 9     at org.hibernate.tuple.entity.PojoEntityTuplizer.setPropertyValues(PojoEntityTuplizer.java:200)
10     at org.hibernate.persister.entity.AbstractEntityPersister.setPropertyValues(AbstractEntityPersister.java:3566)
11     at org.hibernate.engine.TwoPhaseLoad.initializeEntity(TwoPhaseLoad.java:129)
12     at org.hibernate.loader.Loader.initializeEntitiesAndCollections(Loader.java:854)
13     at org.hibernate.loader.Loader.doQuery(Loader.java:729)
14     at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
15     at org.hibernate.loader.Loader.doList(Loader.java:2220)
16     at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2104)
17     at org.hibernate.loader.Loader.list(Loader.java:2099)
18     at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:378)
19     at org.hibernate.hql.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:338)
20     at org.hibernate.engine.query.HQLQueryPlan.performList(HQLQueryPlan.java:172)
21     at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1121)
22     at org.hibernate.impl.QueryImpl.list(QueryImpl.java:79)
23     at com.c503.poss.dao.disaster.DsDisasterDamageDaoImpl.queryByPage(DsDisasterDamageDaoImpl.java:78)
24     at com.c503.poss.service.disaster.DsDisasterDamageServiceImpl.findByCommon(DsDisasterDamageServiceImpl.java:107)
25     at com.c503.poss.service.disaster.DsDisasterDamageServiceImpl.findDisasterDamage(DsDisasterDamageServiceImpl.java:94)
26     at com.c503.poss.ctrl.disaster.DsDisasterDamageController.findDisasterDamage(DsDisasterDamageController.java:218)
27     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
28     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
29     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
30     at java.lang.reflect.Method.invoke(Method.java:606)
31     at org.springframework.web.bind.annotation.support.HandlerMethodInvoker.doInvokeMethod(HandlerMethodInvoker.java:710)
32     at org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:167)
33     at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:414)
34     at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:402)
35     at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:771)
36     at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:716)
37     at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:647)
38     at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:563)
39     at javax.servlet.http.HttpServlet.service(HttpServlet.java:643)
40     at javax.servlet.http.HttpServlet.service(HttpServlet.java:723)
41     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
42     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
43     at com.c503.poss.ctrl.sm.SecurityFilter.doFilter(SecurityFilter.java:73)
44     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
45     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
46     at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
47     at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
48     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
49     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
50     at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
51     at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
52     at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
53     at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
54     at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
55     at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
56     at org.apache.coyote.http11.Http11AprProcessor.process(Http11AprProcessor.java:879)
57     at org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.process(Http11AprProtocol.java:617)
58     at org.apache.tomcat.util.net.AprEndpoint$Worker.run(AprEndpoint.java:1760)
59     at java.lang.Thread.run(Thread.java:745)

3. 数据库相关表字段设计，相关字段为data_size和data_time_length

4. 出问题的实体类为：红色的double字体处出错

  1 package com.c503.poss.model.disaster;
  2 
  3 import java.util.Date;
  4 
  5 
  6 /**
  7  * DsImageVideoData entity. @author MyEclipse Persistence Tools
  8  */
  9 
 10 public class DsImageVideoData {
 11 
 12 
 13     // Fields    
 14 
 15      private Integer id;
 16      private DsTower dsTowerByEndTowerId;
 17      private DsLine dsLine;
 18      private DsTower dsTowerByStartTowerId;
 19      private DsDisaster dsDisaster;
 20      private String disasterTypeName;
 21      private String dataKind;
 22      private String dataName;
 23      private String storagePath;
 24      private double dataSize;
 25      private double dataTimeLength;
 26      private String dataFormat;
 27      private String dataType;
 28      private String phase;
 29      private Date time;
 30 
 31 
 32     // Constructors
 33 
 34     /** default constructor */
 35     public DsImageVideoData() {
 36     }
 37 
 38     /** minimal constructor */
 39     public DsImageVideoData(DsLine dsLine, DsDisaster dsDisaster) {
 40         this.dsLine = dsLine;
 41         this.dsDisaster = dsDisaster;
 42     }
 43     
 44    
 45     // Property accessors
 46 
 47     public Integer getId() {
 48         return this.id;
 49     }
 50     
 51     public void setId(Integer id) {
 52         this.id = id;
 53     }
 54 
 55     public DsTower getDsTowerByEndTowerId() {
 56         return this.dsTowerByEndTowerId;
 57     }
 58     
 59     public void setDsTowerByEndTowerId(DsTower dsTowerByEndTowerId) {
 60         this.dsTowerByEndTowerId = dsTowerByEndTowerId;
 61     }
 62 
 63     public DsLine getDsLine() {
 64         return this.dsLine;
 65     }
 66     
 67     public void setDsLine(DsLine dsLine) {
 68         this.dsLine = dsLine;
 69     }
 70 
 71     public DsTower getDsTowerByStartTowerId() {
 72         return this.dsTowerByStartTowerId;
 73     }
 74     
 75     public void setDsTowerByStartTowerId(DsTower dsTowerByStartTowerId) {
 76         this.dsTowerByStartTowerId = dsTowerByStartTowerId;
 77     }
 78 
 79     public DsDisaster getDsDisaster() {
 80         return this.dsDisaster;
 81     }
 82     
 83     public void setDsDisaster(DsDisaster dsDisaster) {
 84         this.dsDisaster = dsDisaster;
 85     }
 86 
 87     public String getDisasterTypeName() {
 88         return this.disasterTypeName;
 89     }
 90     
 91     public void setDisasterTypeName(String disasterTypeName) {
 92         this.disasterTypeName = disasterTypeName;
 93     }
 94 
 95     public String getDataKind() {
 96         return this.dataKind;
 97     }
 98     
 99     public void setDataKind(String dataKind) {
100         this.dataKind = dataKind;
101     }
102 
103     public String getDataName() {
104         return this.dataName;
105     }
106     
107     public void setDataName(String dataName) {
108         this.dataName = dataName;
109     }
110 
111     public String getStoragePath() {
112         return this.storagePath;
113     }
114     
115     public void setStoragePath(String storagePath) {
116         this.storagePath = storagePath;
117     }
118 
119     public double getDataSize() {
120         return this.dataSize;
121     }
122     
123     public void setDataSize(double dataSize) {
124         this.dataSize = dataSize;
125     }
126 
127     public double getDataTimeLength() {
128         return this.dataTimeLength;
129     }
130     
131     public void setDataTimeLength(double dataTimeLength) {
132         this.dataTimeLength = dataTimeLength;
133     }
134 
135     public String getDataFormat() {
136         return this.dataFormat;
137     }
138     
139     public void setDataFormat(String dataFormat) {
140         this.dataFormat = dataFormat;
141     }
142 
143     public String getDataType() {
144         return this.dataType;
145     }
146     
147     public void setDataType(String dataType) {
148         this.dataType = dataType;
149     }
150 
151     public String getPhase() {
152         return this.phase;
153     }
154     
155     public void setPhase(String phase) {
156         this.phase = phase;
157     }
158 
159     public Date getTime() {
160         return this.time;
161     }
162     
163     public void setTime(Date time) {
164         this.time = time;
165     }
166 }

5. 改进

　　将步骤3中实体类中的属性dataSize和dataTimeLength的数据类型给回Double（包括setter和getter中的方法）

【重要参考】：http://www.cnblogs.com/lucky2u/p/3498046.html