发布于 2015-05-15 03:59:42 | 251 次阅读 | 评论: 0 | 来源: 网友投递

这里有新鲜出炉的精品教程，程序狗速度看过来！

fastjson JSON 解析器

fastjson 是一个性能很好的 Java 语言实现的 JSON 解析器和生成器，来自阿里巴巴的工程师开发。

---

研究了下FastJson的使用方法，感觉比较好使，可以创建json字符串，也可以根据json字符串来创建对象

 * 1、class Json.parseObject(String,clazz.class);//将一个JSON字符串转换成约定的Java实体对象

 * 2、String Json.toString(class,boolean);//将一个实体对象转化成JSON字符串

 * 3、String Json.toJSONString(collection,boolean);//将一个集合中的数据转化成JSON字符串

 * 4、JSONArray Json.parseJSONArray(String);//将一个JSON字符串转换成JSONArray

package com.flag.app;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Vector;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONArray;
import com.flag.app.Entity.Welcome;

/**
 * 主要使用的API有下面几个：
 *
 * 1、class Json.parseObject(String,clazz.class);//将一个JSON字符串转换成约定的Java实体对象
 * 2、String Json.toString(class,boolean);//将一个实体对象转化成JSON字符串
 * 3、String Json.toJSONString(collection,boolean);//将一个集合中的数据转化成JSON字符串
 * 4、JSONArray Json.parseJSONArray(String);//将一个JSON字符串转换成JSONArray
 * 
 * @author Administrator
 *
 */
public class FastJsonMain {

	static String json = "{"study": 10,"study_course_count": 10, "recieved_reg_form_count": 0,"unread_count": 5,"teach_course_count": 8,"avatar": "1316634098115-02-57","user_id": 201,"nickname": "Asus人名"}";
	static String arrayAyy="[[14,"小学语文"],[154,"美食"],[72,"高中物理"],null,[50,"高中化学"],[15,"小学数学"],[13"英语"],null,[1,"其他英语培训"],null]";
	
			
	
	/**
	 * Json 转换 实体类 提示：FastJson在映射实体上非常棒， json有的K，实体没有，依然不影响解析..
	 */
	private void Json2Eetity() {
		// TODO Auto-generated method stub
		Welcome welcome = JSON.parseObject(json, Welcome.class);
		System.out.println(welcome.toString());
		System.out.println(welcome.getNickname());
	}

	/**
	 * 实体类 转换 Json
	 */
	private void Eetity2Json() {
		// TODO Auto-generated method stub
		Welcome welcome = new Welcome(2, 3, 4, 5, "imagUrl", 11, "Mers");
		String json = JSON.toJSONString(welcome, true);
		System.out.println("实体转换Json：" + json);
	}

	/**
	 * list集合转json格式字符串
	 */
	public void list2Json() {
		List<Welcome> list = new ArrayList<Welcome>();
		Welcome welcome1 = new Welcome(2, 3, 4, 5, "imagUrl", 11, "Mers");
		Welcome welcome2 = new Welcome(22, 33, 44, 55, "imag", 65, "Kers");
		Welcome welcome3 = new Welcome(64, 33, 34, 05, "imagUrl", 43, "Wers");
		Welcome welcome4 = new Welcome(62, 75, 41, 25, "imagUrl", 109, "Oers");
		list.add(welcome1);
		list.add(welcome2);
		list.add(welcome3);
		list.add(welcome4);
		String json = JSON.toJSONString(list, true);
		System.out.println("ist集合转json格式字符串 :" + json);
	}
	
	
	/**
	 * String转换 JSONArray
	 * 并且去除null
	 */
	private void String2JSONArray() {
		// TODO Auto-generated method stub
		JSONArray array=JSONArray.parseArray(arrayAyy);
		System.out.println(array);
		System.out.println("长度: "+array.size());
		
		Collection nuCon = new Vector(); 
		nuCon.add(null); 
		array.removeAll(nuCon);
		
		System.out.println(array);
		System.out.println("长度: "+array.size());
	}

	public static void main(String[] args) {
		FastJsonMain main = new FastJsonMain();
		
		main.Json2Eetity();
		System.out.println(" ");
		
		main.Eetity2Json();
		System.out.println("");
		
		main.list2Json();
		System.out.println(" ");
		
		main.String2JSONArray();
	}

}

package com.flag.app.Entity;

public class Welcome {

	/**
	 * 报名的个数
	 */
	public int study_course_count;

	/**
	 * 收到报名个数
	 */
	public int recieved_reg_form_count;

	/**
	 * push推送课程报名个数
	 */
	public int unread_count;

	/**
	 * 开设课程
	 */
	public int teach_course_count;

	/**
	 * 用户头像
	 */
	public String avatar;

	/**
	 * 用户ID
	 */
	public int user_id;

	/**
	 * 用户名
	 */
	public String nickname;

	
	
	
	public Welcome() {
		super();
		// TODO Auto-generated constructor stub
	}
	
	
	

	public Welcome(int study_course_count, int recieved_reg_form_count,
			int unread_count, int teach_course_count, String avatar,
			int user_id, String nickname) {
		super();
		this.study_course_count = study_course_count;
		this.recieved_reg_form_count = recieved_reg_form_count;
		this.unread_count = unread_count;
		this.teach_course_count = teach_course_count;
		this.avatar = avatar;
		this.user_id = user_id;
		this.nickname = nickname;
	}




	public int getStudy_course_count() {
		return study_course_count;
	}

	public void setStudy_course_count(int study_course_count) {
		this.study_course_count = study_course_count;
	}

	public int getRecieved_reg_form_count() {
		return recieved_reg_form_count;
	}

	public void setRecieved_reg_form_count(int recieved_reg_form_count) {
		this.recieved_reg_form_count = recieved_reg_form_count;
	}

	public int getUnread_count() {
		return unread_count;
	}

	public void setUnread_count(int unread_count) {
		this.unread_count = unread_count;
	}

	public int getTeach_course_count() {
		return teach_course_count;
	}

	public void setTeach_course_count(int teach_course_count) {
		this.teach_course_count = teach_course_count;
	}

	public String getAvatar() {
		return avatar;
	}

	public void setAvatar(String avatar) {
		this.avatar = avatar;
	}

	public int getUser_id() {
		return user_id;
	}

	public void setUser_id(int user_id) {
		this.user_id = user_id;
	}

	public String getNickname() {
		return nickname;
	}

	public void setNickname(String nickname) {
		this.nickname = nickname;
	}

	@Override
	public String toString() {
		return "Welcome [study_course_count=" + study_course_count
				+ ", recieved_reg_form_count=" + recieved_reg_form_count
				+ ", unread_count=" + unread_count + ", teach_course_count="
				+ teach_course_count + ", avatar=" + avatar + ", user_id="
				+ user_id + ", nickname=" + nickname + "]";
	}
	
	
	

}

执行的结果如下： Welcome [study_course_count=10, recieved_reg_form_count=0, unread_count=5, teach_course_count=8, avatar=1316634098115-02-57, user_id=201, nickname=Asus人名] Asus人名   实体转换Json：{ "avatar":"imagUrl", "nickname":"Mers", "recieved_reg_form_count":3, "study_course_count":2, "teach_course_count":5, "unread_count":4, "user_id":11 } ist集合转json格式字符串 :[ { "avatar":"imagUrl", "nickname":"Mers", "recieved_reg_form_count":3, "study_course_count":2, "teach_course_count":5, "unread_count":4, "user_id":11 }, { "avatar":"imag", "nickname":"Kers", "recieved_reg_form_count":33, "study_course_count":22, "teach_course_count":55, "unread_count":44, "user_id":65 }, { "avatar":"imagUrl", "nickname":"Wers", "recieved_reg_form_count":33, "study_course_count":64, "teach_course_count":5, "unread_count":34, "user_id":43 }, { "avatar":"imagUrl", "nickname":"Oers", "recieved_reg_form_count":75, "study_course_count":62, "teach_course_count":25, "unread_count":41, "user_id":109 } ]   [[14,"小学语文"],[154,"美食"],[72,"高中物理"],null,[50,"高中化学"],[15,"小学数学"],[13,"英语"],null,[1,"其他英语培训"],null] 长度: 10 [[14,"小学语文"],[154,"美食"],[72,"高中物理"],[50,"高中化学"],[15,"小学数学"],[13,"英语"],[1,"其他英语培训"]] 长度: 7