详解Spring全局异常处理的三种方式

2024-07-13 10:06:18

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在J2EE项目的开发中，不管是对底层的数据库操作过程，还是业务层的处理过程，还是控制层的处理过程，都不可避免会遇到各种可预知的、不可预知的异常需要处理。每个过程都单独处理异常，系统的代码耦合度高，工作量大且不好统一，维护的工作量也很大。那么，能不能将所有类型的异常处理从各处理过程解耦出来，这样既保证了相关处理过程的功能较单一，也实现了异常信息的统一处理和维护？答案是肯定的。下面将介绍使用Spring MVC统一处理异常的解决和实现过程

使用Spring MVC提供的SimpleMappingExceptionResolver
实现Spring的异常处理接口HandlerExceptionResolver 自定义自己的异常处理器
使用@ExceptionHandler注解实现异常处理

(一) SimpleMappingExceptionResolver

使用这种方式具有集成简单、有良好的扩展性、对已有代码没有入侵性等优点，但该方法仅能获取到异常信息，若在出现异常时，对需要获取除异常以外的数据的情况不适用。

@Configuration@EnableWebMvc@ComponentScan(basePackages = {"com.balbala.mvc.web"})public class WebMVCConfig extends WebMvcConfigurerAdapter{ @Bean  public SimpleMappingExceptionResolver simpleMappingExceptionResolver()  {    SimpleMappingExceptionResolver b = new SimpleMappingExceptionResolver();    Properties mappings = new Properties();    mappings.put("org.springframework.web.servlet.PageNotFound", "page-404");    mappings.put("org.springframework.dao.DataAccessException", "data-access");    mappings.put("org.springframework.transaction.TransactionException", "transaction-Failure");    b.setExceptionMappings(mappings);    return b;  }}

(二) HandlerExceptionResolver

相比第一种来说,HandlerExceptionResolver能准确显示定义的异常处理页面,达到了统一异常处理的目标

1.定义一个类实现HandlerExceptionResolver接口,这次贴一个自己以前的代码

package com.athena.common.handler;import com.athena.common.constants.ResponseCode;import com.athena.common.exception.AthenaException;import com.athena.common.http.RspMsg;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.web.servlet.HandlerExceptionResolver;import org.springframework.web.servlet.ModelAndView;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import java.io.IOException;import java.io.PrintWriter;/**  * Created by sam on 15/4/14.  */public class GlobalHandlerExceptionResolver implements HandlerExceptionResolver {   private static final Logger LOG = LoggerFactory.getLogger(GlobalHandlerExceptionResolver.class);           /**     * 在这里处理所有得异常信息     */    @Override    public ModelAndView resolveException(HttpServletRequest req,                     HttpServletResponse resp, Object o, Exception ex) {      ex.printStackTrace();       if (ex instanceof AthenaException) {        //AthenaException为一个自定义异常      ex.printStackTrace();           printWrite(ex.toString(), resp);         return new ModelAndView();     }      //RspMsg为一个自定义处理异常信息的类     //ResponseCode为一个自定义错误码的接口    RspMsg unknownException = null;       if (ex instanceof NullPointerException) {          unknownException = new RspMsg(ResponseCode.CODE_UNKNOWN, "业务判空异常", null);    } else {           unknownException = new RspMsg(ResponseCode.CODE_UNKNOWN, ex.getMessage(), null);    }         printWrite(unknownException.toString(), resp);        return new ModelAndView();    }   /**     * 将错误信息添加到response中     *     * @param msg     * @param response     * @throws IOException     */    public static void printWrite(String msg, HttpServletResponse response) {        try {             PrintWriter pw = response.getWriter();           pw.write(msg);           pw.flush();           pw.close();        } catch (Exception e) {            e.printStackTrace();        }    }}

2.加入spring的配置中,这里只贴出了相关部分

import com.athena.common.handler.GlobalHandlerExceptionResolver;import org.springframework.context.annotation.Bean;import com.athena.common.handler.GlobalHandlerExceptionResolver;import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;/**  * Created by sam on 15/4/14.  */public class WebSpringMvcConfig extends WebMvcConfigurerAdapter {  @Bean  public GlobalHandlerExceptionResolver globalHandlerExceptionResolver() {   return new GlobalHandlerExceptionResolver();  }}

(三)@ExceptionHandler

这是笔者现在项目的使用方式,这里也仅贴出了相关部分

1.首先定义一个父类,实现一些基础的方法

package com.balabala.poet.base.spring;import com.google.common.base.Throwables;import com.raiyee.poet.base.exception.MessageException;import com.raiyee.poet.base.utils.Ajax;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.core.annotation.AnnotationUtils;import org.springframework.http.HttpStatus;import org.springframework.web.bind.annotation.ResponseStatus;import org.springframework.web.servlet.ModelAndView;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import java.io.IOException;import java.io.PrintWriter;import java.util.Date;public class BaseGlobalExceptionHandler {     protected static final Logger logger = null;     protected static final String DEFAULT_ERROR_MESSAGE = "系统忙，请稍后再试";    protected ModelAndView handleError(HttpServletRequest req, HttpServletResponse rsp, Exception e, String viewName, HttpStatus status) throws Exception {       if (AnnotationUtils.findAnnotation(e.getClass(), ResponseStatus.class) != null)         throw e;        String errorMsg = e instanceof MessageException ? e.getMessage() : DEFAULT_ERROR_MESSAGE;         String errorStack = Throwables.getStackTraceAsString(e);       getLogger().error("Request: {} raised {}", req.getRequestURI(), errorStack);         if (Ajax.isAjax(req)) {           return handleAjaxError(rsp, errorMsg, status);       }         return handleViewError(req.getRequestURL().toString(), errorStack, errorMsg, viewName);    }     protected ModelAndView handleViewError(String url, String errorStack, String errorMessage, String viewName) {         ModelAndView mav = new ModelAndView();         mav.addObject("exception", errorStack);         mav.addObject("url", url);        mav.addObject("message", errorMessage);      mav.addObject("timestamp", new Date());         mav.setViewName(viewName);       return mav;      }     protected ModelAndView handleAjaxError(HttpServletResponse rsp, String errorMessage, HttpStatus status) throws IOException {          rsp.setCharacterEncoding("UTF-8");          rsp.setStatus(status.value());         PrintWriter writer = rsp.getWriter();      writer.write(errorMessage);          writer.flush();          return null;     }     public Logger getLogger() {          return LoggerFactory.getLogger(BaseGlobalExceptionHandler.class);   } }

2.针对你需要捕捉的异常实现相对应的处理方式

package com.balabala.poet.base.spring;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.http.HttpStatus;import org.springframework.web.bind.annotation.ControllerAdvice;import org.springframework.web.bind.annotation.ExceptionHandler;import org.springframework.web.bind.annotation.ResponseStatus;import org.springframework.web.servlet.ModelAndView;import org.springframework.web.servlet.NoHandlerFoundException;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;@ControllerAdvicepublic class GlobalExceptionHandler extends BaseGlobalExceptionHandler {     //比如404的异常就会被这个方法捕获   @ExceptionHandler(NoHandlerFoundException.class)     @ResponseStatus(HttpStatus.NOT_FOUND)      public ModelAndView handle404Error(HttpServletRequest req, HttpServletResponse rsp, Exception e) throws Exception {         return handleError(req, rsp, e, "error-front", HttpStatus.NOT_FOUND);      }     //500的异常会被这个方法捕获   @ExceptionHandler(Exception.class)      @ResponseStatus(HttpStatus.INTERNAL_SERVER_ERROR)    public ModelAndView handleError(HttpServletRequest req, HttpServletResponse rsp, Exception e) throws Exception {        return handleError(req, rsp, e, "error-front", HttpStatus.INTERNAL_SERVER_ERROR);    }     //TODO 你也可以再写一个方法来捕获你的自定义异常   //TRY NOW!!!   @Override     public Logger getLogger() {         return LoggerFactory.getLogger(GlobalExceptionHandler.class);     } }

以上就三种处理方式，希望对大家的学习有所帮助，也希望大家多多支持VeVb武林网。

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