详解Spring全局异常处理的三种方式

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;
@ControllerAdvice
public 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);  
  }
}

来源：http://www.jianshu.com/p/f968b8dcf95a#