首先我的项目是一个为移动端提供的json数据的，当后台报错时如果为移动端返回一个错误页面显得非常不友好，于是通过ControllerAdvice注解返回json数据。

首先创建一个异常处理类：

package com.gefufeng.controller;

import com.gefufeng.common.exception.KnownBizException;

import org.apache.commons.lang.StringUtils;

import org.apache.log4j.LogManager;

import org.apache.log4j.Logger;

import org.springframework.http.HttpStatus;

import org.springframework.web.HttpRequestMethodNotSupportedException;

import org.springframework.web.bind.MissingServletRequestParameterException;

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

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

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

import org.springframework.web.bind.annotation.ResponseStatus;

import javax.servlet.http.HttpServletRequest;

import java.util.HashMap;

import java.util.Map;

/**

 * Created by gefufeng on 16/7/18.

 */

@ControllerAdvice

public class ApplicationControllerExceptionHandler {

    private static final Logger LOGGER = LogManager.getLogger(ApplicationControllerExceptionHandler.class);

    @ExceptionHandler(value = Exception.class)

    @ResponseStatus(HttpStatus.INTERNAL_SERVER_ERROR)

    @ResponseBody

    public Map<String, Object> handlerError(HttpServletRequest req, Exception e) {

        map.put("tip", "此错误说明调用接口失败，失败原因见msg，如果msg为空，联系后台");

        map.put("msg", msg);

        map.put("path", req.getRequestURI());

        map.put("params", req.getParameterMap());

        map.put("status", "0");

        return map;

    }

}

加上ControllerAdvice注解，注意这个类是在controller包下面，因为spring需要扫描到，

代码中的：

@ExceptionHandler(value = Exception.class)

表示捕捉到所有的异常，你也可以捕捉一个你自定义的异常，比如：

    @ExceptionHandler(BusinessException.class)

    @ResponseBody//这里加上这个注解才能返回json数据

    public void handleBizExp(HttpServletRequest request, Exception ex){  

    }  

    @ExceptionHandler(SQLException.class)

    public ModelAndView handSql(Exception ex){

        ModelAndView mv = new ModelAndView();

        return mv;

    }  

然后我在一个接口中故意抛出一个异常：

@RestController

@RequestMapping(value = "/customer",produces = MediaType.APPLICATION_JSON_UTF8_VALUE)

public class CustomerController extends BaseController{

    @Autowired

    CustomerService customerService;

    @RequestMapping(value = "/getcustomer",method = RequestMethod.GET)

    public String getCustomer(){

        logger.info(EnvironmentUtils.isTest());

        List<Customer> customers = customerService.getCustomerList();

        throw new KnownBizException("已知的异常");

    }

}

最后后台返回的数据是：

{

  "msg": "已知的异常",

  "path": "/myschool/customer/getcustomer",

  "tip": "此错误说明调用接口失败，失败原因见msg，如果msg为空，联系后台",

  "params": {},

  "status": "0"

}