工具类

json和pojo对象之间的转换

import java.util.List;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JavaType;
import com.fasterxml.jackson.databind.ObjectMapper;

public class JsonUtils {

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

    /**
     * 将对象转换成json字符串。
     * <p>Title: pojoToJson</p>
     * <p>Description: </p>
     * @param data
     * @return
     */
    public static String objectToJson(Object data) {
    	try {
			String string = MAPPER.writeValueAsString(data);
			return string;
		} catch (JsonProcessingException e) {
			e.printStackTrace();
		}
    	return null;
    }
    
    /**
     * 将json结果集转化为对象
     * 
     * @param jsonData json数据
     * @param clazz 对象中的object类型
     * @return
     */
    public static <T> T jsonToPojo(String jsonData, Class<T> beanType) {
        try {
            T t = MAPPER.readValue(jsonData, beanType);
            return t;
        } catch (Exception e) {
        	e.printStackTrace();
        }
        return null;
    }
    
    /**
     * 将json数据转换成pojo对象list
     * <p>Title: jsonToList</p>
     * <p>Description: </p>
     * @param jsonData
     * @param beanType
     * @return
     */
    public static <T>List<T> jsonToList(String jsonData, Class<T> beanType) {
    	JavaType javaType = MAPPER.getTypeFactory().constructParametricType(List.class, beanType);
    	try {
    		List<T> list = MAPPER.readValue(jsonData, javaType);
    		return list;
		} catch (Exception e) {
			e.printStackTrace();
		}
    	
    	return null;
    }
    
}

获取异常信息

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

public class ExceptionUtil {

	/**
	 * 获取异常的堆栈信息
	 * 
	 * @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();
		}
	}
}

淘淘商城自定义返回值对象

package com.taotao.common.utils;

import java.util.List;

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

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);
	}
    
	/**
	 * 返回TaotaoResult
	 * @param data
	 * @return
	 */
	//拿到数据
	public static TaotaoResult ok(Object data) {
		return new TaotaoResult(data);
	}
   //没拿到数据
	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;
		}
	}
}