异常处理器

默认处理异常的方式

1、自定义异常处理器

1.1 实现步骤

1. 自定义异常
2. 自定义异常处理器【实现HandlerExceptionResolver】
3. 把异常处理器注入到SpringMVC容器中
4. 测试

1.2 具体实现

• 自定义异常

package com.qf.java2007.ex;

/**
 * @author ghy
 * @version 1.0
 */
public class MoneyException extends RuntimeException {

    public MoneyException() {
        super();
    }

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

    public MoneyException(String message, Throwable cause) {
        super(message, cause);
    }

    public MoneyException(Throwable cause) {
        super(cause);
    }

    protected MoneyException(String message, Throwable cause, boolean enableSuppression, boolean writableStackTrace) {
        super(message, cause, enableSuppression, writableStackTrace);
    }
}

• 自定义异常处理器【实现HandlerExceptionResolver】

• 把异常处理器注入到SpringMVC容器中

package com.qf.java2007.exhandler;

import com.qf.java2007.ex.MoneyException;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerExceptionResolver;
import org.springframework.web.servlet.ModelAndView;

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

/**
 * HandlerExceptionResolver 异常处理器的接口
 * @author ghy
 * @version 1.0
 */
@Component
public class MyExceptionHandler implements HandlerExceptionResolver {

    /**
     * 能够处理controller抛出所有异常
     * @param request
     * @param response
     * @param handler
     * @param ex
     * @return
     */
    @Override
    public ModelAndView resolveException(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) {

            System.out.println("Handler出异常了，我来处理..............." + ex.getClass());

            ModelAndView mav = new ModelAndView();

            if(ex instanceof MoneyException) {
                mav.setViewName("error1");
                mav.addObject("errorMsg", ex.getMessage());
            } else {
                mav.setViewName("error2");
                mav.addObject("errorMsg", "服务器正忙，请稍后重试");
            }

            return mav;
    }
}

• 测试
  • handler

package com.qf.java2007.controller;


import com.qf.java2007.ex.MoneyException;
import com.qf.java2007.pojo.User;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.Date;


/**
 * @author ghy
 * @version 1.0
 */
@Controller
public class Demo4Controller {

    @RequestMapping(value = "/test31")
    public String test31(int num) {
        if(num == 1) {
            //出自定义异常
            throw new MoneyException("钱不够");
        } else if(num == 2) {
            int i=1/0;
        }
        return "success";
    }

}

• 效果

测试效果

2、@ControllerAdvice + @ExceptionHandler

• 自定义异常就是MoneyException
• controller

package com.qf.java2007.controller;


import com.qf.java2007.entity.ResultVO;
import com.qf.java2007.ex.MoneyException;
import com.qf.java2007.pojo.User;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;

import java.util.Date;


/**
 * @author ghy
 * @version 1.0
 */
@Controller
public class Demo4Controller {

    @RequestMapping(value = "/test31")
    public String test31(int num) {
        if(num == 1) {
            //出自定义异常
            throw new MoneyException("钱不够");
        } else if(num == 2) {
            int i=1/0;
        } else if(num == 3) {
            String str = "hello";
            int a = Integer.valueOf(str);
        }
        return "success";
    }

    @RequestMapping("/test32")
    @ResponseBody
    public ResultVO test32(){
        int i = 1/0;
        return new ResultVO(true, "正常", "一个正常的响应");
    }

}

• 异常处理器2

package com.qf.java2007.exhandler;

import com.qf.java2007.entity.ResultVO;
import com.qf.java2007.ex.MoneyException;
import com.qf.java2007.pojo.User;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.servlet.ModelAndView;

import java.util.Date;

/**
 * 根据异常类型指定具体方法去执行
 * @author ghy
 * @version 1.0
 */
@Component
@ControllerAdvice
public class MyControllerAdvice {

    /**
     * 出MoneyException，就会执行如下方法
     * @param ex
     * @return
     */
    @ExceptionHandler(MoneyException.class)
    public ModelAndView catchException1(Exception ex){
        ModelAndView mav = new ModelAndView();
        mav.addObject("errorMsg", ex.getMessage());
        mav.setViewName("error1");
        return mav;
    }

    /**
     * 出ArithmeticException，就会执行如下方法
     * @param ex
     * @return
     */
    @ExceptionHandler(ArithmeticException.class)
    @ResponseBody
    public ResultVO catchException2(Exception ex){
        return new ResultVO(false, ex.getMessage(), "出异常了，已经被处理");
    }

    /**
     * 如果没有能够处理异常的方法，那么就走如下方法【最大的】
     * @param ex
     * @return
     */
    @ExceptionHandler(Exception.class)
    public ModelAndView catchException3(Exception ex){
        ModelAndView mav = new ModelAndView();
        mav.addObject("errorMsg", ex.getMessage());
        mav.setViewName("error2");
        return mav;
    }
}