java数据类型转换____Gson框架对象和JSON转换

package com.cnse.convert.gson;

import java.util.ArrayList;
import java.util.List;

import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;
/**
 * @author Administrator
 * 使用Json的开发包
 */
public class GsonUtil {
	/**
	 * 单个对象间的转换=================================
	 * @param obj
	 * @return
	 */
	public static String objToJson(Object obj){
		Gson g = new Gson();
		return g.toJson(obj);
	}
	public static Object jsonToObj(Class<?> clazz, String JsonStr) throws Exception {
		Gson g = new Gson();
		Object obj = null;
		try {
			obj = g.fromJson(JsonStr, clazz);
		} catch (Exception e) {
			e.printStackTrace();
		}
		return obj;
	}
	/**
	 * 多个对象间的转换=====================================
	 * @param obj
	 * @return
	 */
	public static String objSToJson(Object obj){
		Gson g = new Gson();
		return g.toJson(obj);
	}
	public static List<User> getObjectS(String JsonStr) throws Exception {
		 // json转为带泛型的list  
		Gson g = new Gson();
        List<User> retList = g.fromJson(JsonStr,new TypeToken<List<User>>() {}.getType());  
		return retList;  
	}
	//==============================test
	public static void main(String[] args) throws Exception {
		//初始化对象
		User u1 = new User();
		u1.setUserid(1);
		u1.setUsername("zhangsan");
		u1.setPassword("123456");
		User u2 = new User();
		u2.setUserid(2);
		u2.setUsername("lisi");
		u2.setPassword("8888");
		List<User>list=new ArrayList<User>();
		list.add(u1);
		list.add(u2);
		//==========单个对象间转换
		System.out.println("Gson单个对象转Json串___:"+objToJson(u1));
		User us=(User) jsonToObj(User.class, objToJson(u1));
		System.out.println(us.getUsername());
		//=========多个对象间转换
		System.out.println("Gson的list<Obj>转json串__:"+objToJson(list));
		List<User>userlist =getObjectS(objToJson(list));
		System.out.println("_____"+userlist.get(0).getUsername());
	}
}

//User对象

package com.cnse.convert.fastjson;

/**
 * @author God
 * 用户对象
 */
public class User {
	//general po
	private int userid;
	private String username;
	private String password;
	//encap
	public int getUserid() {
		return userid;
	}
	public void setUserid(int userid) {
		this.userid = userid;
	}
	public String getUsername() {
		return username;
	}
	public void setUsername(String username) {
		this.username = username;
	}
	public String getPassword() {
		return password;
	}
	public void setPassword(String password) {
		this.password = password;
	}

}

//运行结果