SpringMVC異常 · Java框架

## 概述 controller調用service,service調用dao,異常都是向上拋出的,最終DispatcherServlet找異常處理器進行異常的處理.如果沒有異常處理器,就會將異常顯示到頁面上. ## 流程 ![](https://box.kancloud.cn/e5e5f433932137b902f7b3346f1adb75_1304x608.png) ## 默認情況頁面會顯示異常,這樣很不友好.應該有異常調跳轉到錯誤頁面. ~~~ @RequestMapping("index") public String index() { int a = 10 / 0; //模擬異常 return "success"; } ~~~ ![](https://box.kancloud.cn/1a1b9fe4ba261cdf08392b2b26ac6c49_2520x1050.png) ## 步驟 1. 自定義異常類(做提示信息的). 2. 編寫異常處理器. 3. 配置異常處理器(跳轉到提示頁面). ## 代碼自定義異常類: ~~~ package com.like.exception; //自定義異常類 public class MyException extends Exception { //存儲提示信息 private String message; public MyException(String message) { this.message = message; } @Override public String getMessage() { return message; } public void setMessage(String message) { this.message = message; } } ~~~ 自定義異常處理器: ~~~ package com.like.exception; import org.springframework.web.servlet.HandlerExceptionResolver; import org.springframework.web.servlet.ModelAndView; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; //異常處理器 public class MyExceptionResolver implements HandlerExceptionResolver { //當控制器有異常跑出來,配置的異常處理器就會調用此類 @Override //Object o是當前處理器的對象.Exception e是控制器拋出的異常 public ModelAndView resolveException(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) { //處理異常邏輯 //獲取異常對象 MyException ex = null; if (e instanceof MyException) { ex = (MyException) e; } else { e = new MyException("系統正在維護..."); } ModelAndView modelAndView = new ModelAndView(); modelAndView.addObject("errMsg", e.getMessage()); modelAndView.setViewName("error"); return modelAndView; } } ~~~ SpringMVC配置文件: ~~~ <bean id="myException" class="com.like.exception.MyExceptionResolver"></bean> ~~~ 錯誤頁面: ~~~ <%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>Title</title> </head> <body> ${errMsg} </body> </html> ~~~ 控制器部分: ~~~ @RequestMapping("index") public String index() throws MyException { try { //模擬異常 int a = 10 / 0; } catch (Exception e) { //打印異常信息 e.printStackTrace(); //拋出自定義異常 throw new MyException("查詢錯誤"); } return "success"; } ~~~