获取 exception 对象的字符串形式（接口服务返回给调用者）

工具类：

package com.taotao.common.utils;

import java.io.PrintWriter;
import java.io.StringWriter;

public class ExceptionUtil {

    /**
     * 获取异常的堆栈信息（先打印到控制台，再返回字符串形式）
     * 
     * @param t
     * @return
     */
    public static String getStackTrace(Throwable t) {
        StringWriter sw = new StringWriter();
        PrintWriter pw = new PrintWriter(sw);

        try {
            t.printStackTrace(pw);
            return sw.toString();
        } finally {
            pw.close();
        }
    }
}

使用方法：

package com.taotao.rest.controller;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

import com.taotao.common.pojo.TaotaoResult;
import com.taotao.common.utils.ExceptionUtil;
import com.taotao.pojo.TbContent;
import com.taotao.rest.service.ContentService;


@Controller
@RequestMapping("/content")
public class ContentController {
    
    @Autowired
    ContentService contentService;
    
    @RequestMapping("/list/{contentCategoryId}")
    @ResponseBody
    public TaotaoResult getContentList(@PathVariable Long contentCategoryId) {
        //因为是提供接口服务，所以要处理异常，以便返回信息给调用者
        try {
            List<TbContent> list = contentService.getContentList(contentCategoryId);
            return TaotaoResult.ok(list);
        } catch (Exception e) {
            return TaotaoResult.build(500, ExceptionUtil.getStackTrace(e));
        }
    }

}

springMvc Controller层返回结果封装的对象：

package com.taotao.common.pojo;

import java.util.List;

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;

/**
 * 淘淘商城自定义响应结构
 */
public class TaotaoResult {

    // 定义jackson对象
    private static final ObjectMapper MAPPER = new ObjectMapper();

    // 响应业务状态
    private Integer status;

    // 响应消息
    private String msg;

    // 响应中的数据
    private Object data;

    public static TaotaoResult build(Integer status, String msg, Object data) {
        return new TaotaoResult(status, msg, data);
    }

    public static TaotaoResult ok(Object data) {
        return new TaotaoResult(data);
    }

    public static TaotaoResult ok() {
        return new TaotaoResult(null);
    }

    public TaotaoResult() {

    }

    public static TaotaoResult build(Integer status, String msg) {
        return new TaotaoResult(status, msg, null);
    }

    public TaotaoResult(Integer status, String msg, Object data) {
        this.status = status;
        this.msg = msg;
        this.data = data;
    }

    public TaotaoResult(Object data) {
        this.status = 200;
        this.msg = "OK";
        this.data = data;
    }

//    public Boolean isOK() {
//        return this.status == 200;
//    }

    public Integer getStatus() {
        return status;
    }

    public void setStatus(Integer status) {
        this.status = status;
    }

    public String getMsg() {
        return msg;
    }

    public void setMsg(String msg) {
        this.msg = msg;
    }

    public Object getData() {
        return data;
    }

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

    /**
     * 将json结果集转化为TaotaoResult对象
     * 
     * @param jsonData json数据
     * @param clazz TaotaoResult中的object类型
     * @return
     */
    public static TaotaoResult formatToPojo(String jsonData, Class<?> clazz) {
        try {
            if (clazz == null) {
                return MAPPER.readValue(jsonData, TaotaoResult.class);
            }
            JsonNode jsonNode = MAPPER.readTree(jsonData);
            JsonNode data = jsonNode.get("data");
            Object obj = null;
            if (clazz != null) {
                if (data.isObject()) {
                    obj = MAPPER.readValue(data.traverse(), clazz);
                } else if (data.isTextual()) {
                    obj = MAPPER.readValue(data.asText(), clazz);
                }
            }
            return build(jsonNode.get("status").intValue(), jsonNode.get("msg").asText(), obj);
        } catch (Exception e) {
            return null;
        }
    }

    /**
     * 没有object对象的转化
     * 
     * @param json
     * @return
     */
    public static TaotaoResult format(String json) {
        try {
            return MAPPER.readValue(json, TaotaoResult.class);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * Object是集合转化
     * 
     * @param jsonData json数据
     * @param clazz 集合中的类型
     * @return
     */
    public static TaotaoResult formatToList(String jsonData, Class<?> clazz) {
        try {
            JsonNode jsonNode = MAPPER.readTree(jsonData);
            JsonNode data = jsonNode.get("data");
            Object obj = null;
            if (data.isArray() && data.size() > 0) {
                obj = MAPPER.readValue(data.traverse(),
                        MAPPER.getTypeFactory().constructCollectionType(List.class, clazz));
            }
            return build(jsonNode.get("status").intValue(), jsonNode.get("msg").asText(), obj);
        } catch (Exception e) {
            return null;
        }
    }

}