SpringMVC_25_异常处理_ResponseStatusExceptionResolver 和 DefaultHandlerExceptionResovler

ResponseStatusExceptionResolver

• 在异常及异常父类中找到@ResponseStatus注解，然后使用这个注解的属性进行处理。
• 顶一个@ResponseStatus注解修饰的异常类

@ResponseStatus(HttpStatus.UNAUTHORIZED)

public class UnauthorizedException extends RuntimeException{}

• 若在处理器方法中抛出了上述异常：若ExceptionHandlerExceptionResolver不解析异常。由于触发的异常UnauthorizedExceptiuon带有@ResponseStatus注解。因此会被ResponseStatusExceptionResolver解析到。最后响应HttpStatus.UNAYTHORIZED代码给客户端。HttpStatus.UNAUTHORIZED代表响应码401，无权限。关于其他的响应码请参考HttpStatus枚举类型源码。

例子程序：

第一步：在index.jsp写上< a>标签

<br><br>
<a href="testResponseStatusExceptionResolver?i=10">Test ResponseStatusExceptionResolver</a>

第二步：新建一个类UserNameNotMatchPasswordException继承RuntimeException 注意声明@ResponseStatus

UserNameNotMatchPasswordException.java

package com.springmvc.test;


import org.springframework.http.HttpStatus;
import org.springframework.web.bind.annotation.ResponseStatus;

@ResponseStatus(value=HttpStatus.FORBIDDEN,reason = "用户名和密码不匹配！")
public class UserNameNotMatchPasswordException extends RuntimeException{


    private static final long serialVersionUID = 1L;
}

第三步：写handler方法

@RequestMapping("/testResponseStatusExceptionResolver")
public String testResponseStatusExceptionResolver(@RequestParam("i") int i){
    if(i==13){
        throw new UserNameNotMatchPasswordException();
    }
    System.out.println("testResponseStatusExceptionResolver...");
    return "success";
}

我们来看效果,url在i==13的情况下

若handler方法就有@ResponseStatus声明

@ResponseStatus(reason = "测试",value = HttpStatus.NOT_FOUND)
@RequestMapping("/testResponseStatusExceptionResolver")
public String testResponseStatusExceptionResolver(@RequestParam("i") int i){
    if(i==13){
        throw new UserNameNotMatchPasswordException();
    }
    System.out.println("testResponseStatusExceptionResolver...");
    return "success";
}

DefaultHandlerExceptionResovler

index.jsp

<a href="testDefaultHandlerExceptionResolver?i=10">Test DefaultHandlerExceptionResolver</a>

@RequestMapping(value = "/testDefaultHandlerExceptionResolver",method = RequestMethod.POST)
public String testDefaultHandlerExceptionResolver(){
    System.out.println("testDefaultHandlerExceptionResolver...");
    return "success";
}

也就是说，因为< a>提交方法是get，不是post，所以会报错。