json-lib初探

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what is JSON

JSON (JavaScript Object Notation) is a lightweight data-interchange format. It is easy for humans to read and write. It is easy for machines to parse and generate. It is based on a subset of the JavaScript Programming Language, Standard ECMA-262 3rd Edition - December 1999. JSON is a text format that is completely language independent but uses conventions that are familiar to programmers of the C-family of languages, including C, C++, C#, Java, JavaScript, Perl, Python, and many others. 
These properties make JSON an ideal data-interchange language.

 

here is more detail:  http://www.json.org/json-zh.html

经常用的JSON包有两种：json-lib 和 org-lib,这里直接介绍json-lib  两个都差不多。

官网：http://json-lib.sourceforge.net/

 

Json-lib requires (at least) the following dependencies in your classpath:

• jakarta commons-lang 2.5
• jakarta commons-beanutils 1.8.0
• jakarta commons-collections 3.2.1
• jakarta commons-logging 1.1.1
• ezmorph 1.0.6

依赖包可以在这里搜索下载：http://www.docjar.com/

 

最基本的方法：

都是JSONObject的静态方法

 实例：

一个entity类：User.java

package com.hwadee.entity;

public class User {
	private String name;
	private int age;
	public int getAge() {
		return age;
	}
	public void setAge(int age) {
		this.age = age;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	
}

 测试类：JsonTest.java

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

import net.sf.json.JSONArray;
import net.sf.json.JSONObject;

import com.hwadee.entity.User;

public class TestJson {
	public static void main(String[] args) {
		User user=new User();
		user.setAge(1);
		user.setName("test");
//		String jsonStr="{'name':'test','age':'1'}";
		//1：将单个对象转化为JSONString
		JSONObject object=JSONObject.fromObject(user);
		System.out.println(object.toString());
		
//		2：将集合转换为JSONString
//		[{"age":2,"name":"test2"},{"age":3,"name":"test3"},{"age":4,"name":"test4"}]
		List users=new ArrayList();
		User u1=new User();
		u1.setAge(2);
		u1.setName("test2");
		User u2=new User();
		u2.setAge(3);
		u2.setName("test3");
		User u3=new User();
		u3.setAge(4);
		u3.setName("test4");
		users.add(u1);
		users.add(u2);
		users.add(u3);
		JSONArray jsonArray=JSONArray.fromObject(users);
		System.out.println(jsonArray.toString());
                //JsonStr To JsonArray
		String jsons="[{'name':'test','age':'1'},{'name':'test4','age':'4'}]";
		JSONArray array=JSONArray.fromObject(jsons);
		for (int i = 0; i < array.size(); i++) {
			 JSONObject jo=(JSONObject) array.get(i);
			 System.out.println(jo.get("name"));
		}
	}
}

 

 

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