ExceptionFilter

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.lang.exception.ExceptionUtils;
import org.apache.log4j.Logger;

import com.alibaba.fastjson.JSON;
import com.yundaex.common.basic.vo.ResponseVO;
import com.yundaex.common.exception.DefaultResponseException;
import com.yundaex.common.exception.ExceptionHelper;
import com.yundaex.common.exception.WrappedRuntimeException;
import com.yundaex.common.exception.WrappedWriteResponseException;

public class ExceptionFilter implements Filter {

    private static final Logger logger =
            Logger.getLogger(ExceptionFilter.class);

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response,
            FilterChain chain) throws IOException, ServletException {
        HttpServletResponse res = (HttpServletResponse) response;
        HttpServletRequest req = (HttpServletRequest) request;
        try {
           chain.doFilter(req, res);
       } catch (Exception ex) {
            response.setContentType("text/json; charset=utf-8");
               response.setCharacterEncoding("UTF-8");
               if(logger.isDebugEnabled()) {
                   logger.debug("exception has been captured.");
               }
               String fullStackTrace = ExceptionUtils.getFullStackTrace(ex);
               logger.error(fullStackTrace);
               WrappedRuntimeException gre = ExceptionHelper.convert2GeneralResponseException(ex,DefaultResponseException.class);
               ResponseVO responseVO = ExceptionHelper.generateResponseVOFromGenerateResponseException(gre);
               String result = JSON.toJSONString(responseVO);
               if(logger.isDebugEnabled()) {
                   logger.debug(result);
               }
               try{
                   byte[] bytes = result.getBytes("utf8");
                   ServletOutputStream outputStream = response.getOutputStream();
                   outputStream.write(bytes);
               } catch(Exception e){
                   WrappedRuntimeException e1 = new WrappedWriteResponseException("excpetion handler write response occurs error");
                   throw e1;
               }
       }
    }

    @Override
    public void destroy() {

    }

}

/**
 * HTTP 请求响应对应的实体
 * @author JiangWubo-kris
 * @version 2.0
 * @date 2014-10-11
 */
public class ResponseVO {

    /***
     * 处理结果，TURE/FALSE
     */
    private String result;

    /***
     * 返回的数据
     */
    private Object data;

    /***
     * 异常代码
     */
    private String errorCode;

    /***
     * 描述信息
     */
    private Object remark;

    public String getResult() {
        return result;
    }

    public void setResult(String result) {
        this.result = result;
    }

    public Object getData() {
        return data;
    }

    public void setData(Object data) {
        this.data = data;
    }

    public String getErrorCode() {
        return errorCode;
    }

    public void setErrorCode(String errorCode) {
        this.errorCode = errorCode;
    }

    @Override
    public String toString() {
        return "ResponseVO [result=" + result + ", data=" + data
                + ", errorCode=" + errorCode + ", remark=" + remark + "]";
    }

    /**
     * @return the remark
     */
    public Object getRemark() {
        return remark;
    }

    /**
     * @param remark the remark to set
     */
    public void setRemark(Object remark) {
        this.remark = remark;
    }

    public static ResponseVO constructNullValue(){
        ResponseVO responseVO = new ResponseVO();
        responseVO.setResult("TRUE");
        responseVO.setData(new Object());
        return responseVO;
    }
}

web.xml

    <filter>
        <filter-name>exceptionFilter</filter-name>
        <filter-class>com.yundaex.common.exception.filter.ExceptionFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>exceptionFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>