浅谈JSON的数据交换、缓存问题和同步问题

数组类型

[ 
{“name”:”yangjq”,”age”:22}, 
{“name”:”andreny”,”age”:21} 
];

对象类型

[ 
“name”:”andreny”, 
“hobby”:[“sing”,”dance”,”eat”] 
]

graph LR
JSON字符串-->JavaScript对象

var str={"name":"yangjq","age":23};
var obj=eval("("+str+")");
alert(obj.name);

var str={"name":"andreny","age":22};
var obj=JSON.parse(str);
alert(obj.name);

var str={"name":"逗比的二哈","age":9};
var obj=str.parseJSON();
alert(obj.name);

graph LR
JSON对象-->JSON字符串

//第一种方式
Emp emp=new Emp("1","andreny","man");
JSONObject obj=JSONObject.fromObject(emp);
String jsonStr=obj.toString();

//第二种方式
var obj={"name":"yangjq","age":23};
var str1=obj.toJSONString();
//第三种方式
var str2=obj.JSON.stringify();

xhr.open('get','getNumber.do?+Math.random(),true);

package yangjq.test;
import java.util.ArrayList;
import java.util.List;
import net.sf.json.JSONArray;
import net.sf.json.JSONObject;
import yangjq.entity.Friend;
public class JSONtest {
	public static void main(String[] args) {
		System.out.println("---------------");
		test1();
		test2();
		test3();
		test4();
	}
	// java对象转换为json字符串
	public static void test1(){
		Friend f=new Friend();
		f.setName("andreny");
		f.setAge(23);
		JSONObject obj=JSONObject.fromObject(f);
		System.out.println(obj.toString());
	}
	// JSON集合转换为JSON字符串
	public static void test2(){
		List<Friend> fs=new ArrayList<Friend>();
		for (int i=0;i<10;i++){
			Friend f=new Friend();
			f.setName("yangjq"+i);
			f.setAge(12+i);
			fs.add(f);
		}
		JSONArray ja=JSONArray.fromObject(fs);
		System.out.println("-----JSON集合转换为JSON字符串------\n"+fs);
		System.out.println(ja.toString());
	}
	// JSON字符串转换为java对象
	public static void test3(){
		String jsonStr="{\"name\":\"andreny\",\"age\":22}";
		JSONObject obj=JSONObject.fromObject(jsonStr);
		Friend friend=(Friend) JSONObject.toBean(obj,Friend.class);
		System.out.println("-------JSON字符串转换为java对象------\n"+obj.toString());
		System.out.println(friend);
	}
	// JSON字符串转换为java集合
	public static void test4(){
		String jsonStr="[{\"name\":\"yangjq\",\"age\":22}," +
		        "{\"name\":\"andreny\",\"age\":23}]";
		JSONArray obj=JSONArray.fromObject(jsonStr);
		List<Friend> friends=(List<Friend>) JSONArray.toCollection(obj,Friend.class);
		System.out.println("--------JSON字符串转换为java集合---------");
		for (Friend f:friends){
			System.out.println(f);
		}
	}
}

---------------
{"age":23,"name":"andreny"}
-----JSON集合转换为JSON字符串------
[Friend [name=yangjq0, age=12], Friend [name=yangjq1, age=13], Friend [name=yangjq2, age=14], Friend [name=yangjq3, age=15], Friend [name=yangjq4, age=16], Friend [name=yangjq5, age=17], Friend [name=yangjq6, age=18], Friend [name=yangjq7, age=19], Friend [name=yangjq8, age=20], Friend [name=yangjq9, age=21]]
[{"age":12,"name":"yangjq0"},{"age":13,"name":"yangjq1"},{"age":14,"name":"yangjq2"},{"age":15,"name":"yangjq3"},{"age":16,"name":"yangjq4"},{"age":17,"name":"yangjq5"},{"age":18,"name":"yangjq6"},{"age":19,"name":"yangjq7"},{"age":20,"name":"yangjq8"},{"age":21,"name":"yangjq9"}]
-------JSON字符串转换为java对象------
{"name":"andreny","age":22}
Friend [name=andreny, age=22]
--------JSON字符串转换为java集合---------
Friend [name=yangjq, age=22]
Friend [name=andreny, age=23]