JAVA高级面试进阶训练营视频教程

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工程结构：

主方法类：

package com.boot.servlet.api.bootservlet;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.web.servlet.error.ErrorMvcAutoConfiguration;

// @ServletComponentScan //扫描的方式使用servlet
@SpringBootApplication(exclude = ErrorMvcAutoConfiguration.class)
public class BootServletApplication {

    public static void main(String[] args) {
        SpringApplication.run(BootServletApplication.class, args);
    }
}

Setvlet

package com.boot.servlet.api.bootservlet.servlet;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@WebServlet(name = "MyServlet",urlPatterns = "/my")
public class MyServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        System.out.println("执行了servlet请求");
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doPost(request, response);
    }
}

过滤器

package com.boot.servlet.api.bootservlet.filter;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import java.io.IOException;

@WebFilter(filterName = "MyFilter", urlPatterns = "/*")
public class MyFilter implements Filter {
    public void destroy() {
    }

    public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws ServletException, IOException {
        System.out.println("执行filter");
        chain.doFilter(req, resp);
    }

    public void init(FilterConfig config) throws ServletException {

    }

}

监听器

package com.boot.servlet.api.bootservlet.listener;

import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.annotation.WebListener;
import javax.servlet.http.HttpSessionAttributeListener;
import javax.servlet.http.HttpSessionEvent;
import javax.servlet.http.HttpSessionListener;
import javax.servlet.http.HttpSessionBindingEvent;

@WebListener
public class Listener implements ServletContextListener,
        HttpSessionListener, HttpSessionAttributeListener {

    // Public constructor is required by servlet spec
    public Listener() {
    }

    // -------------------------------------------------------
    // ServletContextListener implementation
    // -------------------------------------------------------
    public void contextInitialized(ServletContextEvent sce) {
      /* This method is called when the servlet context is
         initialized(when the Web application is deployed). 
         You can initialize servlet context related data here.
      */
        System.out.println("servlet容器启动");
    }

    public void contextDestroyed(ServletContextEvent sce) {
      /* This method is invoked when the Servlet Context 
         (the Web application) is undeployed or 
         Application Server shuts down.
      */
    }

    // -------------------------------------------------------
    // HttpSessionListener implementation
    // -------------------------------------------------------
    public void sessionCreated(HttpSessionEvent se) {
        /* Session is created. */
    }

    public void sessionDestroyed(HttpSessionEvent se) {
        /* Session is destroyed. */
    }

    // -------------------------------------------------------
    // HttpSessionAttributeListener implementation
    // -------------------------------------------------------

    public void attributeAdded(HttpSessionBindingEvent sbe) {
      /* This method is called when an attribute 
         is added to a session.
      */
    }

    public void attributeRemoved(HttpSessionBindingEvent sbe) {
      /* This method is called when an attribute
         is removed from a session.
      */
    }

    public void attributeReplaced(HttpSessionBindingEvent sbe) {
      /* This method is invoked when an attibute
         is replaced in a session.
      */
    }
}

除了使用注解外还可以使用配置类的方式实现：

package com.boot.servlet.api.bootservlet.config;

import com.boot.servlet.api.bootservlet.filter.MyFilter;
import com.boot.servlet.api.bootservlet.listener.Listener;
import com.boot.servlet.api.bootservlet.servlet.MyServlet;
import org.springframework.boot.SpringBootConfiguration;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.boot.web.servlet.ServletListenerRegistrationBean;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.annotation.Bean;

import java.util.Arrays;

/**
 * 通过配置类的方式引入servlet
 */
@SpringBootConfiguration
public class ServletConfiguration {

    @Bean
    public ServletRegistrationBean<MyServlet> registrationBean() {
        ServletRegistrationBean<MyServlet> bean = new ServletRegistrationBean<>();
        bean.setServlet(new MyServlet());
        bean.setUrlMappings(Arrays.asList("/my"));
        return  bean;
    }

    @Bean
    public FilterRegistrationBean<MyFilter> filterFilterRegistrationBean() {
        FilterRegistrationBean<MyFilter> bean = new FilterRegistrationBean<>();
        bean.setFilter(new MyFilter());
        bean.setUrlPatterns(Arrays.asList("/*"));

        return bean;
    }

    @Bean
    public ServletListenerRegistrationBean<Listener> servletListenerRegistrationBean() {
        ServletListenerRegistrationBean<Listener> listener = new ServletListenerRegistrationBean<>();
        listener.setListener(new Listener());

        return listener;
    }
}

拦截器

package com.boot.servlet.api.bootservlet.interceptor;

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class MyInteceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("postHandle");
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.out.println("afterCompletion");
    }
}

拦截器配置类

package com.boot.servlet.api.bootservlet.config;

import com.boot.servlet.api.bootservlet.interceptor.MyInteceptor;
import org.springframework.boot.SpringBootConfiguration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport;

/**
 * 拦截器配置类
 */
@SpringBootConfiguration
public class MyWebMvcConfiguration extends WebMvcConfigurationSupport {
    @Override
    protected void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new MyInteceptor());
    }
}

 

springBoot自定义错误页面处理

默认读取的静态资源位置:"classpath:/META-INF/resources/", "classpath:/resources/",
"classpath:/static/", "classpath:/public/"

非模板： public/error/xxx.html

​模板的: templates/errror/xxx.html

​ 异常处理：

​ 局部@ExceptionHandler

​ 全局@ControllerAdvice+@ExceptionHandler

 

程序演示

结构：

 

 

package com.example.bootex.exception;

/**
 * 自定义业务异常类
 */
public class BizException extends RuntimeException { public BizException() { super(); } public BizException(String message) { super(message); } public BizException(String message, Throwable cause) { super(message, cause); } public BizException(Throwable cause) { super(cause); } protected BizException(String message, Throwable cause, boolean enableSuppression, boolean writableStackTrace) { super(message, cause, enableSuppression, writableStackTrace); } }

 

 

package com.example.bootex.controller;

import com.example.bootex.exception.BizException; import org.springframework.stereotype.Controller; import org.springframework.ui.Model; import org.springframework.web.bind.annotation.ExceptionHandler; import org.springframework.web.bind.annotation.GetMapping; @Controller public class PageController { /** * 局部异常处理 * @param ex * @param model * @return */ @ExceptionHandler(BizException.class) public String exPage1(Exception ex, Model model) { model.addAttribute("ex", ex); return "/error/biz.html"; } @GetMapping("/e500") public String e500() { throw new RuntimeException("runtime-exception"); } @GetMapping("/add") public String add() { throw new BizException("添加出现异常"); } }

 

 

package com.example.bootex.exception;

import org.springframework.http.HttpStatus; import org.springframework.web.bind.annotation.ControllerAdvice; import org.springframework.web.bind.annotation.ExceptionHandler; import org.springframework.web.bind.annotation.ResponseStatus; /** * 全局业务处理 */ @ControllerAdvice public class GlobalExceptionHandler { @ExceptionHandler(Exception.class) @ResponseStatus(code = HttpStatus.NOT_FOUND) public String e404() { return "error/404.html"; } @ExceptionHandler(RuntimeException.class) @ResponseStatus(code = HttpStatus.INTERNAL_SERVER_ERROR) public String e500() { return "error/500.html"; } }