springboot实战笔记(十四)----springboot异常处理

一前言

在系统中异常的出现是无可避免的，那么对于异常的处理，如何将出现异常后返回给前台不同的提示呢？而且以不同页面效果展示给前端呢？接下来说一下springboot其中常见两种处理异常的方式，自定义 HandlerExceptionResolver 的类处理异常。还有一个是@ControllerAdvice+@ExceptionHandler 注解处理异常。

二自定义 HandlerExceptionResolver

1. pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.5.10.RELEASE</version>
  </parent>
  <groupId>com.bjsxt</groupId>
  <artifactId>18-spring-boot-exception5</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  
  <properties>
  <java.version>1.7</java.version>
  <thymeleaf.version>3.0.2.RELEASE</thymeleaf.version>
  <thymeleaf-layout-dialect.version>2.0.4</thymeleaf-layout-dialect.version>
  </properties>
  
  <dependencies>
  	<!-- springBoot的启动器 -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-thymeleaf</artifactId>
    </dependency>
  </dependencies>
</project>

2.创建Controller

package com.bjsxt.controller;

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

@Controller
public class UsersController {

	@RequestMapping("/showUsers")
	public String showUser(){
		String str = null;
		str.length();
		//空指针异常
		return "index";
	}
	
	@RequestMapping("/showUsers2")
	public String showUser2(){
		int a = 100/0;
		//算术异常
		return "index";
	}
}

3.创建前端页面

error1.html

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>错误提示页面-ArithmeticException</title>
</head>
<body>
<h3>算术异常提示页面</h3>
	出错了，请与管理员联系。。。
	<span th:text="${error}"></span>
</body>
</html>

error2.html

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>错误提示页面-NullPointerException</title>
</head>
<body>
<h3>空指针异常提示页面</h3>
	出错了，请与管理员联系。。。
	<span th:text="${error}"></span>
</body>
</html>

4.自定义 HandlerExceptionResolver 类

package com.bjsxt.exception;

import java.util.Properties;

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

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.servlet.HandlerExceptionResolver;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.handler.SimpleMappingExceptionResolver;

/**
 * 通过实现HandlerExceptionResolver接口做全局异常处理
 */
@Configuration
public class GlobalException implements HandlerExceptionResolver {

	@Override
	public ModelAndView resolveException(HttpServletRequest request, HttpServletResponse response, Object handler,
			Exception ex) {
		ModelAndView mv = new ModelAndView();
		//判断不同异常类型，做不同视图跳转
		if(ex instanceof ArithmeticException){
			mv.setViewName("error1");
		}
		
		if(ex instanceof NullPointerException){
			mv.setViewName("error2");
		}
		mv.addObject("error", ex.toString());
		
		return mv;
	}
}

5.启动测试

三 @ControllerAdvice+@ExceptionHandler 注解处理异常

package com.chp.springbootdemo.Exception;

import java.util.HashMap;
import java.util.Map;

import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ResponseBody;

@ControllerAdvice
public class MyControllerAdvice {
	@ResponseBody
	@ExceptionHandler(value = java.lang.Exception.class)
	public Map<String, Object> myException(Exception ex) {
		Map<String, Object> map = new HashMap<>();
		map.put("code", 500);
		map.put("msg", "出错了,请联系管理员");
		return map;
	}

	@ResponseBody
	@ExceptionHandler(value = java.lang.NullPointerException.class)
	public Map<String, Object> myException2(Exception ex) {
		Map<String, Object> map = new HashMap<>();
		map.put("code", -500);
		map.put("msg", "空指针异常");
		return map;
	}

	//自定义异常
	@ResponseBody
	@ExceptionHandler(value=com.chp.springbootdemo.Exception.MyException.class)
	public Map<String, Object> myException3(Exception ex) {
		Map<String, Object> map = new HashMap<>();
		map.put("code", -800);
		map.put("msg", ex.getMessage());
		return map;
	}
}

自定义的异常：

package com.chp.springbootdemo.Exception;

public class MyException extends RuntimeException {
	
	public MyException() {
		super();
		// TODO Auto-generated constructor stub
	}

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

springboot实战笔记(十四)----springboot异常处理

一 前言

二 自定义 HandlerExceptionResolver

三 @ControllerAdvice+@ExceptionHandler 注解处理异常

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