SpringMVC -- 梗概--源码--贰--异常管理

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附：实体类

Class ： User

package com.c61.entity;import java.text.SimpleDateFormat;
import java.util.Date;import org.springframework.format.annotation.DateTimeFormat;import com.alibaba.fastjson.annotation.JSONField;public class User {
private Integer id;
private String name;
//@DateTimeFormat(pattern="yyyy-MM-dd HH:mm:ss")
@DateTimeFormat(pattern="yyyy-MM-dd")//定制在接收请求参数时的日期格式
@JSONField(format="yyyy-MM-dd")//作用在java序列化成json时
private Date birth;
private String dateStr; public String getDateStr() {
return dateStr;
}
public void setDateStr(String dateStr) {
this.dateStr = dateStr;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Date getBirth() {
return birth;
}
public void setBirth(Date birth) {
this.birth = birth;
SimpleDateFormat format=new SimpleDateFormat("yyyy-MM-dd");
this.dateStr=format.format(birth);
}
@Override
public String toString() {
return "User [id=" + id + ", name=" + name + ", birth=" + birth + "]";
}
public User(){}
public User(Integer id, String name, Date birth) {
super();
this.id = id;
this.name = name;
this.birth = birth;
}}

Class ： LoginErrorException

package com.c61.exception;public class LoginErrorException extends RuntimeException{ public LoginErrorException(){}
public LoginErrorException(String msg){
super(msg);
}
}

Class ： AException

package com.c61.exception;public class AException extends RuntimeException{ public AException(){}
public AException(String msg){
super(msg);
}
}

Class ： UserServiceImpl

package com.c61.service;import com.c61.exception.AException;
import com.c61.exception.LoginErrorException;public class UserServiceImpl implements UserService{ public void login(String username, String password) {
//登录业务
if(!"c61".equals(username)){
//日志
throw new LoginErrorException("用户名无效");
}else if(!"123".equals(password)){
//日志
throw new LoginErrorException("密码无效");
}else if(username.length()<10){
throw new AException("test");
}
//正常的登录逻辑控制
//......
}
}

1.配置web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5"
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<display-name></display-name>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list> 
<servlet>
<servlet-name>mvc61</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:mvc62.xml</param-value>
</init-param>

<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>mvc61</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping> 
<filter>
<filter-name>encoding61</filter-name>
<filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>

<init-param>
<param-name>encoding</param-name>
<param-value>utf-8</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>encoding61</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
</web-app>

2.配置SpringMVC.xml

<?xml version="1.0" encoding="utf-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.2.xsd
http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd"> 
<context:component-scan base-package="com.c61.controller"></context:component-scan>

<mvc:annotation-driven>
<mvc:message-converters>
<bean class="com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter">
<property name="supportedMediaTypes">
<list>

<value>application/json</value>
</list>
</property>
</bean>
</mvc:message-converters>
</mvc:annotation-driven>

<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="/"></property>
<property name="suffix" value=".jsp"></property>
</bean>

<mvc:default-servlet-handler/> 
<bean class="com.c61.ex.resolver.MyExceptionResolver"></bean> 

<mvc:interceptors>
<mvc:interceptor>

<mvc:mapping path="/inter/**"/>
<mvc:mapping path="/a/b"/>
<mvc:mapping path="/c/**"/>
<mvc:exclude-mapping path="/inter/test/*"/>
<mvc:exclude-mapping path="/c/b/**"/>

<bean class="com.c61.interceptor.MyInterceptor"/>
</mvc:interceptor>
<mvc:interceptor>

<mvc:mapping path="/inter/test"/>

<bean class="com.c61.interceptor.MyInterceptor2"/>
</mvc:interceptor>
</mvc:interceptors>

<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">

<property name="MaxUploadSize" value="2097152"></property>
</bean>

<bean id="captcha" class="com.google.code.kaptcha.servlet.KaptchaExtend">
<constructor-arg>
<props>

<prop key="kaptcha.border">no</prop>
<prop key="kaptcha.border.color">105,179,90</prop>
<prop key="kaptcha.border.thickness">20</prop>
<prop key="kaptcha.textproducer.font.color">black</prop>
<prop key="kaptcha.image.width">200</prop>
<prop key="kaptcha.image.height">50</prop>
<prop key="kaptcha.textproducer.font.size">40</prop>
<prop key="kaptcha.session.key">code61</prop>
<prop key="kaptcha.textproducer.char.length">4</prop>
<prop key="kaptcha.textproducer.font.names">Arial,Courier</prop>

</props>
</constructor-arg>
</bean>
</beans>

3.配置控制器

Class ： ExceptionController

package com.c61.controller;import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;import com.c61.service.UserService;
import com.c61.service.UserServiceImpl;@Controller
@RequestMapping("/ex")
public class ExceptionController { /*private UserService us=new UserServiceImpl();
public String login(String username,String password){
try{
us.login(username, password);
}catch(LoginErrorException e){
return "redirect:/login.jsp";
}catch(AException e){
return "redirect:/xxx.jsp";
}catch(Exception e){ }
return "forward:/index.jsp";
}*/
private UserService us=new UserServiceImpl();
@RequestMapping("/login")
public String login(String username,String password){
us.login(username,password);
return "forward:/index.jsp";
}
}

4.定制异常管理器

Class ： MyExceptionResolver

package com.c61.ex.resolver;import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;import org.apache.commons.fileupload.FileUploadBase.SizeLimitExceededException;
import org.springframework.web.multipart.MaxUploadSizeExceededException;
import org.springframework.web.servlet.HandlerExceptionResolver;
import org.springframework.web.servlet.ModelAndView;import com.c61.exception.AException;
import com.c61.exception.LoginErrorException;/*
* 异常处理器：所有Controller中抛出的所有异常，都由此处理器接收并处理。
*/
public class MyExceptionResolver implements HandlerExceptionResolver{ /**
* 主体逻辑：自动捕获Controller中的异常,每当Controller中抛出异常时，就会执行。
* param:ex=当前抛出的异常
* req=请求对象
* res=响应对象
* handler=抛出异常的控制器方法
*/
public ModelAndView resolveException(HttpServletRequest req,
HttpServletResponse res, Object handler, Exception ex) {
System.out.println(ex.getClass());
//System.out.println(req.getClass()+" "+res.getClass()+" "+handler.getClass());
System.out.println("异常处理~~~~"+ex.getMessage());
ModelAndView mav=new ModelAndView();
//识别异常
if(ex instanceof LoginErrorException){
mav.setViewName("redirect:/error1.jsp");
}else if(ex instanceof AException){
mav.setViewName("redirect:/error2.jsp");
}else if(ex instanceof MaxUploadSizeExceededException){
mav.setViewName("redirect:/error4.jsp");
}else{
mav.setViewName("redirect:/error3.jsp");
}
return mav;
}}

5.声明异常管理器

XML ： SpringMVC.xml

<bean class="com.c61.ex.resolver.MyExceptionResolver"></bean>

6.配置视图

View ： errer1.jsp

<%@ page language="java" import="java.util.*" pageEncoding="ISO-8859-1"%>
<%
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>My JSP 'index.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">

</head> <body>
This is my error1 JSP page. <br>
</body>
</html>

View ： errer2.jsp

View ： errer3.jsp

View ： errer4.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>My JSP 'index.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">

</head> <body>
请上传小于2M的文件
</body>
</html>

异常管理

定制异常管理器

public class MyExceptionResolver implements HandlerExceptionResolver{
/**
* 主体逻辑：自动捕获Controller中的异常,每当Controller中抛出异常时，就会执行。
* param:ex=当前抛出的异常
* req=请求对象
* res=响应对象
* handler=抛出异常的控制器方法
* 返回值：ModelAndView=用来返回错误页面
*/
public ModelAndView resolveException(HttpServletRequest req,
HttpServletResponse res, Object handler, Exception ex) {
ModelAndView mav=new ModelAndView();
//识别异常
if(ex instanceof LoginErrorException){
mav.setViewName("redirect:/error1.jsp");
}else if(...){}
...
return mav;
}
}

声明

异常管理器作用

作用：统一抽取了所有控制器中的异常处理逻辑
抽取前：
public String login(String username,String password){
try{
us.login(username, password);
}catch(LoginErrorException e){
return "redirect:/login.jsp";
}catch(AException e){
return "redirect:/xxx.jsp";
}catch(Exception e){ }
return "forward:/index.jsp";
}
抽取后：
public String login(String username,String password){
us.login(username,password);
return "forward:/index.jsp";
}

啦啦啦