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  • SpringMVC中的异常处理集锦

    1 描述 
    在J2EE项目的开发中，不管是对底层的数据库操作过程，还是业务层的处理过程，还是控制层的处理过程，都不可避免会遇到各种可预知的、不可预知的异常需要处理。每个过程都单独处理异常，系统的代码耦合度高，工作量大且不好统一，维护的工作量也很大。 
    那么，能不能将所有类型的异常处理从各处理过程解耦出来，这样既保证了相关处理过程的功能较单一，也实现了异常信息的统一处理和维护？答案是肯定的。下面将介绍使用Spring MVC统一处理异常的解决和实现过程。 
    2 分析 
    Spring MVC处理异常常见有4种方式： 
    （1）使用Spring MVC提供的简单异常处理器SimpleMappingExceptionResolver； 
    （2）实现Spring的异常处理SimpleMappingExceptionResolver自定义自己的异常处理器； 

    （3）实现HandlerExceptionResolver 接口自定义异常处理器 
    （4）使用注解@ExceptionHandler实现异常处理； 

    3 实战

    一:使用Spring MVC提供的简单异常处理器SimpleMappingExceptionResolver

    源码介绍:

    1.lib包（jar包）和web.xml配置

    <?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" version="2.5">
  <display-name></display-name>
  <servlet>
    <servlet-name>springmvc</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>classpath:applicationContext.xml</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
    <servlet-name>springmvc</servlet-name>
    <url-pattern>*.do</url-pattern>
  </servlet-mapping>
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
</web-app>
    View Code

    2.index.jsp（测试页面入口）和 error.jsp（有错误则会跳到此页面）和 hello.jsp（没错误则会跳到此页面）

    <%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
    String path = request.getContextPath();
    String basePath = request.getScheme() + "://"
            + request.getServerName() + ":" + request.getServerPort()
            + path + "/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">

<title>异常处理器测试</title>
</head>
<body>
    <form action="frist.do" method="post">
        <input type="submit" value="测试" />
    </form>
</body>
</html>
    View Code
    <%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    <title>这是错误页面</title>
  </head>
  <body>
       这是错误页面  ${ex.message }
  </body>
</html>
    View Code
    <%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    <title>成功欢迎页面</title>
  </head>
  <body>
       你竟然没报错<br/>
  </body>
</html>
    View Code

    3.MyController,java(定义自己的处理器)

    package cn.zhang.controller;
//定义自己的处理器
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

@Controller
public class MyController{
   
    @RequestMapping(value="/frist.do",produces="text/html;charset=utf-8",method=RequestMethod.POST)
    public String frist(){
        //制造一个异常
        int i=5/0;
        System.out.println(i);
        return "forward:/hello.jsp";
    }
}
    View Code

    4.applicationContext.xml(Spring的配置文件)

    <?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    xsi:schemaLocation="
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
        http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <!-- 使用注解方式完成映射 -->
    <context:component-scan base-package="cn.zhang.controller"></context:component-scan>
    <!-- mvc的注解驱动 -->
    <mvc:annotation-driven />
    <!-- 注册系统异常处理器 -->
    <bean
        class="org.springframework.web.servlet.handler.SimpleMappingExceptionResolver">
        <property name="defaultErrorView" value="error.jsp"></property>
        <property name="exceptionAttribute" value="ex"></property>
    </bean>

</beans>
    View Code

    测试展示:

    点击测试，由于我们在自己的处理器制造了一个异常，所以它会跳到错误页面

    二:实现Spring的异常处理接口SimpleMappingExceptionResolver自定义自己的异常处理器

    源码介绍:

    1.lib包和web.xml一样（不做解释）

    2.error包中是指定错误页面

      ageerrors.jsp

    <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
    String path = request.getContextPath();
    String basePath = request.getScheme() + "://"
            + request.getServerName() + ":" + request.getServerPort()
            + path + "/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>年龄错误页面</title>
</head>
<body>年龄错误   ${ex.message }
</body>
</html>
    View Code

      nameerrors.jsp

    <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    <title>名字错误页面</title>
  </head>
  <body>
   名字错误
   ${ex.message }
  </body>
</html>
    View Code

    3.MyController.java

    package cn.zhang.controller;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import cn.zhang.exception.AgeException;
import cn.zhang.exception.NameException;
import cn.zhang.exception.UserException;

//定义自己的处理器

@Controller
public class MyController{
   
    @RequestMapping(value="/frist.do")
    public String frist(Model model,String name,int age) throws UserException{
        if (name.equals("admin")) {
            throw new NameException("用户名错误");    
        }
        if (age>50) {
            throw new AgeException("年龄过大");
        }
        return "forward:/hello.jsp";
    }
}
    View Code

    4.exception包下，指定我们的异常类

     UserException.java

    package cn.zhang.exception;
//定义UserException继承Exception
public class UserException extends Exception {

    private static final long serialVersionUID = 1L;

    public UserException() {
        super();
        // TODO Auto-generated constructor stub
    }

    public UserException(String message) {
        super(message);
        // TODO Auto-generated constructor stub
    }
    
}
    View Code

     AgeException.java

    package cn.zhang.exception;
//继承UserException父类
public class AgeException extends UserException {

    private static final long serialVersionUID = 1L;

    public AgeException() {
        super();
        // TODO Auto-generated constructor stub
    }

    public AgeException(String message) {
        super(message);
        // TODO Auto-generated constructor stub
    }
    
    

}
    View Code

     NameException.java

    package cn.zhang.exception;
//继承UserException父类
public class NameException extends UserException {

    private static final long serialVersionUID = 1L;

    public NameException() {
        super();
        // TODO Auto-generated constructor stub
    }

    public NameException(String message) {
        super(message);
        // TODO Auto-generated constructor stub
    }

}
    View Code

    5.applicationContext.xml(Spring的配置文件)

    <?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    xsi:schemaLocation="
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
        http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <!-- 使用注解方式完成映射 -->
    <context:component-scan base-package="cn.zhang.controller"></context:component-scan>
    <!-- mvc的注解驱动 -->
    <mvc:annotation-driven />
    <!-- 实现Spring的异常处理接口HandlerExceptionResolver 自定义自己的异常处理器 -->
    <bean
        class="org.springframework.web.servlet.handler.SimpleMappingExceptionResolver">
        <property name="defaultErrorView" value="error.jsp"></property>
        <property name="exceptionAttribute" value="ex"></property>
        <!-- 指定错误到指定页面 -->
        <property name="exceptionMappings">
            <props>
                <prop key="cn.zhang.exception.AgeException">error/ageerrors.jsp</prop>
                <prop key="cn.zhang.exception.NameException">error/nameerrors.jsp</prop>
            </props>
        </property>

    </bean>

</beans>
    View Code

    结果展示:

     三:实现HandlerExceptionResolver 接口自定义异常处理器 

     要修改的代码:

     1.MyHandlerExceptionResolver.java--定义自己的异常处理器（实现HandlerExceptionResolver接口）

    package cn.zhang.resolvers;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.web.servlet.HandlerExceptionResolver;
import org.springframework.web.servlet.ModelAndView;
import cn.zhang.exception.AgeException;
import cn.zhang.exception.NameException;
/**
 * 定义自己的异常处理器（实现HandlerExceptionResolver接口）
 * @author zhangzong
 *
 */
public class MyHandlerExceptionResolver implements HandlerExceptionResolver{

    public ModelAndView resolveException(HttpServletRequest request,
            HttpServletResponse response, Object handler, Exception ex) {
        
        ModelAndView  mv=new ModelAndView();
        mv.addObject("ex",ex);
        
        mv.setViewName("/errors.jsp");
        

        if(ex instanceof NameException){
            mv.setViewName("/error/nameerrors.jsp");
        }
        
        if(ex instanceof AgeException){
            mv.setViewName("/error/ageerrors.jsp");
        }
        
        return mv;
    }
    
}
    View Code

     2.applicationContext.xml

    <?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    xsi:schemaLocation="
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
        http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <!-- 使用注解方式完成映射 -->
    <context:component-scan base-package="cn.zhang.controller"></context:component-scan>
    <!-- mvc的注解驱动 -->
    <mvc:annotation-driven />
    <!-- 注册自定义异常处理器 -->
     <bean class="cn.zhang.resolvers.MyHandlerExceptionResolver"/>
</beans>
    View Code

     其他的相同，不作解释

     四:使用注解@ExceptionHandler实现异常处理

     

    源码介绍:

    1.其他配置相同（不做解释）

    2.MyController.java--继承我们自己定义的注解异常处理器MyHandlerExceptionResolver

    package cn.zhang.controller;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import cn.zhang.exception.AgeException;
import cn.zhang.exception.NameException;
import cn.zhang.exception.UserException;
import cn.zhang.resolvers.MyHandlerExceptionResolver;

//定义自己的处理器
//继承我们自己定义的注解异常处理器MyHandlerExceptionResolver
@Controller
public class MyController extends MyHandlerExceptionResolver{
   
    @RequestMapping(value="/frist.do")
    public String frist(Model model,String name,int age) throws UserException{
        if (name.equals("admin")) {
            throw new NameException("用户名错误");    
        }
        if (age>50) {
            throw new AgeException("年龄过大");
        }
        return "forward:/hello.jsp";
    }
}
    View Code

    3.MyHandlerExceptionResolver.java--定义自己的异常处理器（使用注解）

    package cn.zhang.resolvers;


import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.servlet.ModelAndView;
import cn.zhang.exception.AgeException;
import cn.zhang.exception.NameException;
/**
 * 定义自己的异常处理器（使用注解）
 * @author zhangzong
 *
 */
@Controller
public class MyHandlerExceptionResolver{

    @ExceptionHandler
    public ModelAndView resolveException(Exception ex) {
        
        ModelAndView  mv=new ModelAndView();
        mv.addObject("ex",ex);
        
        mv.setViewName("/errors.jsp");
        

        if(ex instanceof NameException){
            mv.setViewName("/error/nameerrors.jsp");
        }
        
        if(ex instanceof AgeException){
            mv.setViewName("/error/ageerrors.jsp");
        }
        
        return mv;
    }
    
}
    View Code

    4.applicationContext.xml

    <?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    xsi:schemaLocation="
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
        http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <!-- 使用注解方式完成映射 -->
    <context:component-scan base-package="cn.zhang.controller"></context:component-scan>
    <!-- mvc的注解驱动 -->
    <mvc:annotation-driven />

    <!-- 注册自定义异常处理器 -->
     <bean class="cn.zhang.resolvers.MyHandlerExceptionResolver"/>
</beans>
    View Code

    效果和上相同，这里不做展示
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  • 原文地址：https://www.cnblogs.com/zhangzongle/p/6087500.html
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