SpingMvc中的异常处理-优快云博客

本文链接：https://blog.youkuaiyun.com/afjklafjklajflafja/article/details/120715430

一.处理异常的方式

Spring3.0中对异常的处理方法一共提供了两种：

第一种是使用HandlerExceptionResolver接口。

第二种是在Controller类内部使用@ExceptionHandler注解。

二.使用HandlerExceptionResolver接口实现异常处理

直接切入架构，配置的什么都不说了,相信这个大家都会

使用这种方式只需要实现resolveException方法，该方法返回一个ModelAndView对象，在方法内部对异常的类型进行判断，然后返回合适的ModelAndView对象，如果该方法返回了null，则Spring会继续寻找其他的实现了HandlerExceptionResolver 接口的Bean。换句话说，Spring会搜索所有注册在其环境中的实现了HandlerExceptionResolver接口的Bean，逐个执行，直到返回了一个ModelAndView对象。

案例描述：

打开首页看到的是注册页面：

既然是案例，我在这里就伪造了注册的时候用户名只能是hyj 密码的要求是只能大于6位数。

用户名错误：

密码错误：

用户名和密码都填写正确，跳到注册成功页面

看代码吧：

web.xml

<?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:springmvc.xml</param-value>
    </init-param>
  </servlet>
  <servlet-mapping>
    <servlet-name>springmvc</servlet-name>
    <url-pattern>*.do</url-pattern>
  </servlet-mapping>
  <welcome-file-list>
    <welcome-file>regist.jsp</welcome-file>
  </welcome-file-list>
</web-app>

regist.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>
  </head>
  <body>
  <form action="exception.do" method="post">
      <table>
        <tr>
          <td>用户名:</td>
          <td><input type="text" name="name"/></td>
        </tr>
        <tr>
          <td>用户密码:</td>
          <td><input type="password" name="pwd" /></td>
        </tr>
         <tr>
          <td colspan="2"><input type="submit" value="注册"/></td>
        </tr>
      </table>
    </form>
  </body>
</html>

nameerroe.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>
    <title>用户名错误页面</title>
  </head>
  <body>
    用户名错误<br/>
    错误信息：${ex.message}
  </body>
</html>

pwderror.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>密码错误页面</title>
  </head>
  <body>
  密码错误
  错误信息：${ex.message}
  </body>
</html>

success.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>成功</title>
  </head>
  
  <body>
    注册成功
  </body>
</html>

spingmvc.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:tx="http://www.springframework.org/schema/tx"
    xmlns:aop="http://www.springframework.org/schema/aop" xmlns:mvc="http://www.springframework.org/schema/mvc"
    xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="
        http://www.springframework.org/schema/beans 
        http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/tx
       http://www.springframework.org/schema/tx/spring-tx.xsd
       http://www.springframework.org/schema/aop
       http://www.springframework.org/schema/aop/spring-aop.xsd
       http://www.springframework.org/schema/mvc
       http://www.springframework.org/schema/mvc/spring-mvc.xsd
        http://www.springframework.org/schema/context
       http://www.springframework.org/schema/context/spring-context.xsd
        ">
        <!-- 注解包扫描器 -->
        <context:component-scan base-package="cn.controller"></context:component-scan>
         <bean class="cn.exception.MyException"></bean>
</beans>

实体类：User.java

package cn.entity;

public class User {
  private String name;
  private String pwd;
public User(String name, String pwd) {
    super();
    this.name = name;
    this.pwd = pwd;
}
public User() {
    super();
    // TODO Auto-generated constructor stub
}
public String getName() {
    return name;
}
public void setName(String name) {
    this.name = name;
}
public String getPwd() {
    return pwd;
}
public void setPwd(String pwd) {
    this.pwd = pwd;
}
  
}

NameException.java

package cn.exception;

public class NameException extends UserException{

public NameException() {
super();
}

public NameException(String message) {
super(message);
}

}

package cn.exception;
public class PwdException extends UserException {

    public PwdException() {
        super();
    }

    public PwdException(String message) {
        super(message);
    }

}

UsersException.java

package cn.exception;
public class UserException extends Exception {
    public UserException() {
        super();
    }
    public UserException(String message) {
        super(message);
    }
}

MyException.java

package cn.exception;

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

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

/**
 * 实现HandlerExceptionResolver接口，进行异常处理
 * @author hyj
 *
 */
public class MyException implements HandlerExceptionResolver{
    @Override
    public ModelAndView resolveException(HttpServletRequest request,
            HttpServletResponse response, Object arg2, Exception ex) {
        ModelAndView mv=new ModelAndView();
        mv.addObject("ex", ex);
        mv.setViewName("error.jsp");
        if(ex instanceof NameException){
            mv.setViewName("nameerroe.jsp");
        }
        if(ex instanceof PwdException){
            mv.setViewName("pwderror.jsp");
        }
        return mv;
    }
}

MyController.java

package cn.controller;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

import cn.entity.User;
import cn.exception.NameException;
import cn.exception.PwdException;
@Controller
public class MyController {
   @RequestMapping(value="/exception.do")
   public String returnObject(User user) throws Exception{
       if(!"hyj".equals(user.getName())){
           throw new NameException("用户名错误");
       }
       if(user.getPwd().length()<6){
           throw new PwdException("密码必须大于6位数");
       }
       return "success.jsp";
   }
}

二.使用注解@ExceptionHandler实现异常处理

上面红色框的部分是要读者在前面项目中做更改的地方。

加上一个BaseController.java类：

package cn.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.servlet.ModelAndView;

import cn.exception.NameException;
import cn.exception.PwdException;
@Controller
public class BaseController {
    /**
     * 用户名异常
     * @param ex
     * @return
     */
    @ExceptionHandler(NameException.class)
    public ModelAndView HandlerNameException(Exception ex){
        ModelAndView mv=new ModelAndView();
        mv.addObject("ex", ex);
        mv.setViewName("nameerroe.jsp");
        return mv;
    }
    /**
     * 密码异常
     * @param ex
     * @return
     */
    @ExceptionHandler(PwdException.class)
    public ModelAndView HandlerPwdException(Exception ex){
        ModelAndView mv=new ModelAndView();
        mv.addObject("ex", ex);
        mv.setViewName("pwderror.jsp");
        return mv;
    }
    /**
     * 如果除了用户名异常，密码异常，其余的异常将被这个方法捕获到
     * @param ex
     * @return
     */
    @ExceptionHandler(Exception.class)
    public ModelAndView HandlerException(Exception ex){
        ModelAndView mv=new ModelAndView();
        mv.addObject("ex", ex);
        mv.setViewName("error.jsp");
        return mv;
    }
    
    
    
    
}

在MyController继承BaseController

package cn.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

import cn.entity.User;
import cn.exception.NameException;
import cn.exception.PwdException;
@Controller
public class MyController extends BaseController{
   @RequestMapping(value="/exception.do")
   public String returnObject(User user) throws Exception{
       if(!"hyj".equals(user.getName())){
           throw new NameException("用户名错误");
       }
       if(user.getPwd().length()<6){
           throw new PwdException("密码必须大于6位数");
       }
       return "success.jsp";
   }
   
}

spingmvc.xml中只用写一个包扫描器，是注解生效

<?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:tx="http://www.springframework.org/schema/tx"
    xmlns:aop="http://www.springframework.org/schema/aop" xmlns:mvc="http://www.springframework.org/schema/mvc"
    xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="
        http://www.springframework.org/schema/beans 
        http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/tx
       http://www.springframework.org/schema/tx/spring-tx.xsd
       http://www.springframework.org/schema/aop
       http://www.springframework.org/schema/aop/spring-aop.xsd
       http://www.springframework.org/schema/mvc
       http://www.springframework.org/schema/mvc/spring-mvc.xsd
        http://www.springframework.org/schema/context
       http://www.springframework.org/schema/context/spring-context.xsd
        ">
        <!-- 注解包扫描器 -->
        <context:component-scan base-package="cn.controller"></context:component-scan>
</beans>

案例代码下载地址：

第一个案例：

http://git.oschina.net/hyjcode/SpringMvc/tree/master/SpringMvc-Exception-myself?dir=1&filepath=SpringMvc-Exception-myself&oid=cfc0883b35170c567b6be8b349d8e23cae8346af&sha=d42645f75fb9384c88c64498e316d66b4295eee3

第二个案例：

http://git.oschina.net/hyjcode/SpringMvc/tree/master/SpringMvc-Exception-annotation?dir=1&filepath=SpringMvc-Exception-annotation&oid=35df89870b4a64301b7a5baa4960b570cee35597&sha=051a90009bd14a02431b46d4b1845ae4caf30e3b