Spring全局异常处理的三种方式

2016-05-17 本文已影响13213人 MacSam

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);    
      }

  }

以上就三种处理方式,希望对大家有点帮助~

Spring全局异常处理的三种方式

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