Json二次学习、补充

最新推荐文章于 2024-08-19 10:43:17 发布

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一、json对应的基础

1、JSON 数据的书写格式是：名称/值对    "firstName" : "John"

2、JSON 值
     JSON 值可以是：1、数字（整数或浮点数）2、字符串（在双引号中）3、逻辑值（true 或 false）4、数组（在方括号中）5、对象（在花括号中）6、null

3、JSON 对象
     JSON 对象在花括号中书写，对象可以包含多个名称/值对：{ "firstName":"John" , "lastName":"Doe" }

4、JSON 数组
     JSON 数组在方括号中书写：数组可包含多个对象
     {
	"employees": [
		{ "firstName":"John" , "lastName":"Doe" },
		{ "firstName":"Anna" , "lastName":"Smith" },
		{ "firstName":"Peter" , "lastName":"Jones" }
	]
    }

5、JSON 文件
JSON 文件的文件类型是 ".json"
JSON 文本的 MIME 类型是 "application/json"

二、通过json语句，分析语句对应的实体类，

这里次啊用:hijson工具以及火狐：restclient

1、语句：http://zhbj.qianlong.com/static/api/news/categories.json

2、返回json：

{"retcode":200,"data":[{"id":10000,"title":"新闻","type":1,"children":[{"id":10007,"title":"北京","type":1,"url":"http://zhbj.qianlong.com/static/api/news/10007/list_1.json"},{"id":10006,"title":"中国","type":1,"url":"http://zhbj.qianlong.com/static/api/news/10006/list_1.json"},{"id":10008,"title":"国际","type":1,"url":"http://zhbj.qianlong.com/static/api/news/10008/list_1.json"},{"id":10014,"title":"文娱","type":1,"url":"http://zhbj.qianlong.com/static/api/news/10014/list_1.json"},{"id":10010,"title":"体育","type":1,"url":"http://zhbj.qianlong.com/static/api/news/10010/list_1.json"},{"id":10091,"title":"生活","type":1,"url":"http://zhbj.qianlong.com/static/api/news/10091/list_1.json"},{"id":10012,"title":"旅游","type":1,"url":"http://zhbj.qianlong.com/static/api/news/10012/list_1.json"},{"id":10095,"title":"科技","type":1,"url":"http://zhbj.qianlong.com/static/api/news/10095/list_1.json"},{"id":10009,"title":"军事","type":1,"url":"http://zhbj.qianlong.com/static/api/news/10009/list_1.json"},{"id":10011,"title":"财经","type":1,"url":"http://zhbj.qianlong.com/static/api/news/10011/list_1.json"},{"id":10093,"title":"时尚","type":1,"url":"http://zhbj.qianlong.com/static/api/news/10093/list_1.json"},{"id":10192,"title":"倍儿逗","type":1,"url":"http://zhbj.qianlong.com/static/api/news/10192/list_1.json"}]},{"id":10002,"title":"专题","type":10,"url":"http://zhbj.qianlong.com/static/api/news/10002/list_1.json","url1":"http://zhbj.qianlong.com/static/api/news/10002/list1_1.json"},{"id":10003,"title":"组图","type":2,"url":"http://zhbj.qianlong.com/static/api/news/10003/list_1.json"},{"id":10004,"title":"互动","type":3,"excurl":"http://zhbj.qianlong.com/static/api/news/comment/exc_1.json","dayurl":"http://zhbj.qianlong.com/static/api/news/comment/day_1.json","weekurl":"http://zhbj.qianlong.com/static/api/news/comment/week_1.json"},{"id":10005,"title":"投票","type":4,"url":"http://zhbj.qianlong.com/static/api/news/vote/vote_1.json"}],"extend":[10007,10006,10008,10014,10091,10010,10192,10009,10095,10093]}

3、得到bean

import java.util.List;

public class NewsCenterCategory {

	public List<CenterCategory> data;
	public List<Integer> extend;
	public int retcode;
	public static class CenterCategory{
		public List<CenterCategoryItem> children;
		public int id;
		public String title;
		public int type;
		public String url;
		public String url1;
		public String dayurl;
		public String excurl;
		public String weekurl;
	}
	public static class CenterCategoryItem{
		public String id;
		public String title;
		public String type;
		public String url;
	}
	
}

三、由上面的数据结构，完成最后的解析工作：

1、这里利用google的GSON包来解析，案例如下：

package com.json.gson;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;
import com.json.bean.Person;
/*
 * 这里将json的转化和解析都放在一起了，大家可以根据实际需要来转化json字符串和解析json字符串
 */
public class GsonClass {
	public static void main(String[] args) {
		method1();
		method2();
		method3();
		method4();
	}
	
	static void method1(){
		System.out.println("javabean转化示例开始----------");
		Person person = new Person("1","gson",1);
		Gson gson = new Gson();
		//这里将javabean转化成json字符串
		String jsonString = gson.toJson(person);
		System.out.println(jsonString);
		//这里将json字符串转化成javabean对象,
		person = gson.fromJson(jsonString,Person.class);
		System.out.println(person.toString());
		
		System.out.println("javabean转化示例结束----------");
	}
	
	static void method2(){
		System.out.println("List<javabean>转化示例开始----------");
		
		Person person1 = new Person("1","gson1",1);
		Person person2 = new Person("2","gson2",2);
		List<Person> persons = new ArrayList<Person>();
		persons.add(person1);
		persons.add(person2);
		Gson gson = new Gson();
		String jsonString = gson.toJson(persons);
		System.out.println("json字符串:"+jsonString);
		
		//解析json字符串
		List<Person> persons2 = gson.fromJson(jsonString, new TypeToken<List<Person>>(){}.getType());
		//输出解析后的person对象，也可以通过调试模式查看persons2的结构
		System.out.println("person1对象："+persons2.get(0).toString());
		System.out.println("person2对象："+persons2.get(1).toString());
		
		System.out.println("List<javabean>转化示例结束----------");
	}
	
	static void method3(){
		System.out.println("List<String>转化示例开始----------");
		List<String> list = new ArrayList<String>();
		list.add("gson1");
		list.add("gson2");
		list.add("gson3");
		Gson gson = new Gson();
		String jsonString = gson.toJson(list);
		System.out.println("json字符串:"+jsonString);
		
		//解析json字符串
		List<String> list2 = gson.fromJson(jsonString, new TypeToken<List<String>>(){}.getType());
		System.out.println(list2.get(0)+"::"+list2.get(1)+"::"+list2.get(2));
		System.out.println("List<String>转化示例结束----------");

	}
	
	static void method4(){
		System.out.println(" List<Map<String,Object>>转化示例开始----------");
		Map<String,Object> map = new HashMap<String,Object>();
		map.put("key1", "value1");
		map.put("key2", "value2");
		Map<String,Object> map2 = new HashMap<String,Object>();
		map2.put("key1", 1);
		map2.put("key2", 2);
		List<Map<String,Object>> list = new ArrayList<Map<String,Object>>();
		list.add(map);
		list.add(map2);
		Gson gson =  new Gson();
		String jsonString = gson.toJson(list);
		System.out.println("json字符串:"+jsonString);
		//解析json字符串
		List<Map<String,Object>> list2 = gson.fromJson(jsonString, new TypeToken<List<Map<String,Object>>>(){}.getType());
		
		System.out.println("map的key1值"+list2.get(0).get("key1"));
		System.out.println("map的key2值"+list2.get(0).get("key2"));
		System.out.println("ma2p的key1值"+list2.get(1).get("key1"));
		System.out.println("map2的key2值"+list2.get(1).get("key2"));
		
		System.out.println(" List<Map<String,Object>>转化示例结束----------");

	}
	
}