<!DOCTYPE html><html><head><meta charset="UTF-8"><meta http-equiv="pragma" content="no-cache" /><meta http-equiv="cache-control" content="no-cache" /><meta http-equiv="Expires" content="0" /><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>Insert title here</title><script type="text/javascript">var json = {"key":123,"key2":"hello","key3":[1,"nihao",true],"key4":{"key4_1":99,"key4_2":"dani"},"key5":[{"key5_1":199,"key5_2":"dani"},{"key5_3":199,"key5_4":"123dani"}]};/* alert(json.key5[1].key5_4); */var ?str= JSON.stringify(json);//json转成对象//alert(str);var jsonObj = JSON.parse(str);/* alert( jsonObj ); */alert( jsonObj.key3[2] );</script></head><body></body></html>
json对象由在括号括起来，对象中的属性也就是json的key是一个字符串，所以一定要使用双引号引起来。每组key之间使用逗号进行分隔。可以保持的格式很多，客户端和服务器都容易解读
var jsons = {"key1":"abc", // 字符串类型"key2":1234, ?// Number"key3":[1234,"21341","53"], // 数组"key4":{ ???????????????????// json类型"key4_1" : 12,"key4_2" : "kkk"},"key5":[{ ?????????????????// json数组 ???"key5_1_1" : 12, ???"key5_1_2" : "abc"},{ ???"key5_2_1" : 41, ???"key5_2_2" : "bbj"}]};JSON中两个常用的方法。
JSON对象和字符串对象的互转。 注意：JSON大写
JSON.stringify( json ); ??????此方法可以把一个json对象转换成为json字符串 ??
JSON.parse( jsonString ); ?????此方法可以把一个json字符串转换成为json对象
json在java中的操作。常见的有三种情况。
1.java对象和json的转换
2.java对象list集合和json的转换
3.map对象和json的转换
引入谷歌Gson 的jar包
package com.atguigu.bean;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.Map;import org.junit.Test;import com.google.gson.Gson;import com.google.gson.JsonElement;import com.google.gson.reflect.TypeToken;public class GsonTest { ???@Test ???public void getGson(){ ???????????????Person person = new Person(1,"张三"); ???????????????Gson gson = new Gson(); ???????????????//对象转json格式 ???????String json = gson.toJson(person);// ???????System.out.println(json);// ???????System.out.println("=============="); ???????????????//json格式转单个对象 ???????Person fromJson = gson.fromJson(json, Person.class);// ???????System.out.println(fromJson); ???????????????//一群对象呢？ ???????List<Person> list = new ArrayList<Person>(); ???????list.add(new Person(2,"张三1")); ???????????????list.add(new Person(3,"张三3")); ???????????????list.add(new Person(4,"张三4")); ???????????????????????JsonElement jsonTree = gson.toJsonTree(list);// ???????System.out.println(jsonTree); ???????????????List<Person> fromJson2 = gson.fromJson(jsonTree, new TypeToken<List<Person>>(){}.getType());// ???????System.out.println(fromJson2); ???????????} ???@Test ???public void mapJson(){ ???????Map<String,Person> map = new HashMap<String,Person>(); ???????????map.put("1", new Person(1,"haha")); ???????????map.put("2", new Person(2,"2haha")); ???????????map.put("3", new Person(3,"3haha")); ???????????????????????Gson gson = new Gson(); ???????????JsonElement map1 = gson.toJsonTree(map);//map对象保存为json格式 ???????????System.out.println(map1); ???????????//把json格式转换为map对象 ???????????Map<String,Person> fromJson = gson.fromJson(map1, new TypeToken<HashMap<String,Person>>(){}.getType()); ???????????System.out.println(fromJson); ???????????????} ???}
json笔记
原文地址：http://www.cnblogs.com/JavaBlackHole/p/8035343.html