Json的转换

package com.utils;

import java.io.IOException;
import java.util.List;

import org.codehaus.jackson.JsonParseException;
import org.codehaus.jackson.JsonProcessingException;
import org.codehaus.jackson.map.JsonMappingException;
import org.codehaus.jackson.map.ObjectMapper;
import org.codehaus.jackson.type.JavaType;

/**
 * 自定义响应结构
 */
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。
	 *
	 * @param data
	 * @return
	 */
	public static String objectToJson(Object data) throws Exception {
		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
	 *            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) {

		}
		return null;
	}

	/**
	 * 将json数据转换成pojo对象list
	 *
	 * @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;
	}

	/**
	 * 将json结果集转化为对象
	 *
	 * @param jsonData
	 *            json数据
	 *            对象中的object类型
	 * @return
	 * @throws IOException
	 * @throws JsonMappingException
	 * @throws JsonParseException
	 */
	public static <T> T jsonToPojo1(String jsonData, Class<T> beanType)
			throws JsonParseException, JsonMappingException, IOException {

		T t = MAPPER.readValue(jsonData, beanType);
		return t;

	}
	/**
	 * 把一个字符串转换成bean对象
	 * @param str
	 * @param <T>
	 * @return
	 */
	public static <T> T stringToBean(String str, Class<T> clazz) {
		if(str == null || str.length() <= 0 || clazz == null) {
			return null;
		}
		if(clazz == int.class || clazz == Integer.class) {
			return (T)Integer.valueOf(str);
		}else if(clazz == String.class) {
			return (T)str;
		}else if(clazz == long.class || clazz == Long.class) {
			return  (T)Long.valueOf(str);
		}else {
			return com.alibaba.fastjson.JSON.toJavaObject(com.alibaba.fastjson.JSON.parseObject(str), clazz);
		}
	}

}