fastjson的JSONArray和JSONObject[通俗易懂]

大家好，又见面了，我是你们的朋友全栈君。

什么是JSON?

JSON(JavaScript Object Notation) 是一种轻量级的数据交换格式。 易于人阅读和编写。同时也易于机器解析和生成。 它基于javascript Programming Language, Standard ECMA-262 3rd Edition – December 1999的一个子集。 JSON采用完全独立于语言的文本格式，但是也使用了类似于C语言家族的习惯（包括C, C++, C#, Java, JavaScript, Perl, Python等）。 这些特性使JSON成为理想的数据交换语言。 现在我们就来研究一下fastJson。

Fastjson是国内著名的电子商务互联网公司阿里巴巴内部开发的用于java后台处理json格式数据的一个工具包，包括“序列化”和“反序列化”两部分，它具备如下特征

1. 速度最快，测试表明，fastjson具有极快的性能，超越任其他的java json parser。包括自称最快的jackson。

2. 功能强大，完全支持java bean、集合、Map、日期、Enum，支持范型，支持自省。

3. 无依赖，能够直接运行在Java SE 5.0以上版本

4. 支持Android。

5. 这是fastJson的网址：http://code.alibabatech.com/wiki/display/FastJSON/Overview其中包含了json数据处理的教程，jar下载地址，example样例等

JSONObject 与JSONArray

• JSONObject

json对象，就是一个键对应一个值，使用的是大括号{ }，如：{key:value}

• JSONArray

json数组，使用中括号[ ],只不过数组里面的项也是json键值对格式的

Json对象中是添加的键值对,JSONArray中添加的是Json对象

例子

/** * Created by wanggs on 2017/7/27. */

public class JsonTest { 
   
    public static void main(String[] args) {

       // Json对象中是添加的键值对,JSONArray中添加的是Json对象

        JSONObject jsonObject = new JSONObject();
        JSONObject jsonObject1 = new JSONObject();
        JSONArray jsonArray = new JSONArray();
        jsonObject1.put("001","tom");

        // JSONObject 对象中添加键值对
        jsonObject.put("key","value");
        // 将JSONObject对象添加到json数组中
        jsonArray.add(jsonObject);
        jsonArray.add(jsonObject1);

        System.out.println(jsonArray.toString());

        // 输出结果: [{"key":"value"},{"001":"tom"}]

    }
}

复制

---

先来个官方例子

package com.wanggs.com.wanggs.json.fastjson;

import java.util.List;

/** * Created by wanggs on 2017/7/27. */
public class Group { 
   
    private int id;
    private String name;
    List<User> users;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public List<User> getUsers() {
        return users;
    }

    public void setUsers(List<User> users) {
        this.users = users;
    }
}

class User{
    private int id;
    private String name;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

复制

---

package com.wanggs.com.wanggs.json.fastjson;

import com.alibaba.fastjson.JSON;

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

/** * Created by wanggs on 2017/7/27. */
public class FastJsonTest {
    public static void main(String[] args) {
        Group group = new Group();
        group.setId(0);
        group.setName("admin");

        User user = new User();
        user.setId(001);
        user.setName("guest");
        User user1 = new User();
        user1.setId(002);
        user1.setName("root");
        List<User> users = new ArrayList<User>();
        users.add(user);
        users.add(user1);

        group.setUsers(users);

        String json = JSON.toJSONString(group);
        System.out.println(json);

        // 输出: {
  
  "id":0,"name":"admin","users":[{
  
  "id":1,"name":"guest"},{
  
  "id":2,"name":"root"}]}
    }
}

复制

下面给出fastJson处理json数据格式的代码样例：

package test.com.wanggs.com.wanggs.json.fastjson;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;
import com.alibaba.fastjson.serializer.SerializerFeature;
import com.wanggs.com.wanggs.json.fastjson.People;
import org.junit.Test;

import static org.junit.Assert.*;

/** * Created by wanggs on 2017/7/27. */
public class FastJsonTestTest { 
   

    /** * 序列化 */
    @Test
    public void toJsonString() {
        People people = new People("001","tom",12);
        String text = JSON.toJSONString(people);
        System.out.println(text);

        // 输出结果: {"age":12,"id":"001","name":"tom"}
    }

    /** * 反序列为Json对象 */
    @Test
    public void parseJsonObject(){
        String text = "{\"age\":12,\"id\":\"001\",\"name\":\"tom\"}";
        People people = (People) JSON.parseObject(text,People.class);
        System.out.println("parseBeanObject()方法：people==" + people.getId() + "," + people.getName() + "," + people.getAge());

        // 输出结果为: parseBeanObject()方法：people==001,tom,12
    }

    /** * 将javaBean转化为json对象 */
    @Test
    public void bean2Json(){
        People people = new People("002","jack",23);
        JSONObject jsonObject = (JSONObject) JSON.toJSON(people);
        System.out.println("bean2Json()方法：jsonObject==" + jsonObject);

        // 输出结果: bean2Json()方法：jsonObject=={"name":"jack","id":"002","age":23}
    }

    /** * 全序列化 直接把java bean序列化为json文本之后，能够按照原来的类型反序列化回来。支持全序列化，需要打开SerializerFeature.WriteClassName特性 */
    @Test
    public void parseJSONAndBeanEachother(){
        People people = new People("002","jack",23);
        SerializerFeature[] featureArr = { SerializerFeature.WriteClassName };
        String text = JSON.toJSONString(people, featureArr);

        System.out.println("parseJSONAndBeanEachother()方法：text==" + text);
        // 输出结果：parseJSONAndBeanEachother()方法：text=={"@type":"com.wanggs.com.wanggs.json.fastjson.People","age":23,"id":"002","name":"jack"}
      People people1 = (People) JSON.parse(text);
        System.out.println("parseJSONAndBeanEachother()方法：People==" + people1.getId() + "," + people1.getName() + "," + people1.getAge());
        // 输出结果：userObj==testFastJson001,maks,105
    }

}

复制

附：javaBean类People.java

package com.wanggs.com.wanggs.json.fastjson;

/** * Created by wanggs on 2017/7/27. */
public class People { 
   
    private String id;
    private String name;
    private int age;

    public People() {
    }

    public People(String id, String name, int age) {
        this.id = id;
        this.name = name;
        this.age = age;
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }
}

复制

在深入Json

package test.com.wanggs.com.wanggs.json.fastjson;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONArray;
import com.wanggs.com.wanggs.json.fastjson.Address;
import com.wanggs.com.wanggs.json.fastjson.People;
import org.junit.Test;

import java.util.*;

import static org.junit.Assert.*;

/** * Created by wanggs on 2017/7/27. */
public class FastJsonTest1Test {
    /** * 数组转json字符串 */
    @Test
    public void array2Json() {
        String[] arr = {
  
  "bill", "green", "maks", "jim"};
        String jsonText = JSON.toJSONString(arr);
        System.out.println("array2Json()方法：jsonText==" + jsonText);
        // 输出结果：jsonText==["bill","green","maks","jim"]
    }

    /** * json格式字符串转数组 */
    @Test
    public void json2Array() {
        String jsonText = "[\"bill\",\"green\",\"maks\",\"jim\"]";
        JSONArray jsonArray = JSON.parseArray(jsonText);
        System.out.println("json2Array()方法：jsonArray==" + jsonArray);
        // 输出结果：jsonArray==["bill","green","maks","jim"]
    }

    /** * 数组转json格式字符串 */
    @Test
    public void array2Json2() {
        People people = new People("001", "tom", 12);
        People people1 = new People("002", "jack", 23);
        People people2 = new People("003", "mair", 22);

        People[] peoples = new People[]{people, people1, people2};

        String jsonText = JSON.toJSONString(peoples);
        System.out.println("array2Json2()方法：jsonText==" + jsonText);

        //输出结果：array2Json2()方法：jsonText==[{
  
  "age":12,"id":"001","name":"tom"},{
  
  "age":23,"id":"002","name":"jack"},{
  
  "age":22,"id":"003","name":"mair"}]

    }

    /** * json格式字符串转数组 */
    @Test
    public void json2Array2() {
        String jsonText = "[{\"age\":12,\"id\":\"001\",\"name\":\"tom\"},{\"age\":23,\"id\":\"002\",\"name\":\"jack\"},{\"age\":22,\"id\":\"003\",\"name\":\"mair\"}]";
        JSONArray jsonArr = JSON.parseArray(jsonText);
        System.out.println("json2Array2()方法：jsonArr==" + jsonArr);
        // 输出结果：json2Array2()方法：jsonArr==[{
  
  "name":"tom","id":"001","age":12},{
  
  "name":"jack","id":"002","age":23},{
  
  "name":"mair","id":"003","age":22}]

    }

    /** * list集合转json格式字符串 */
    @Test
    public void list2Json() {
        List<People> list = new ArrayList<People>();
        list.add(new People("001", "tom", 12));
        list.add(new People("002", "jack", 23));
        list.add(new People("003", "mair", 22));

        String jsonText = JSON.toJSONString(list);
        System.out.println("list2Json()方法：jsonText==" + jsonText);

        // 输出的结果为: [{
  
  "age":12,"id":"001","name":"tom"},{
  
  "age":23,"id":"002","name":"jack"},{
  
  "age":22,"id":"003","name":"mair"}]
    }


    /** * map转json格式字符串 */
    @Test
    public void map2Json() {
        Map map = new HashMap();
        Address address1 = new Address("广东省","深圳市","科苑南路","580053");
        map.put("address1", address1);
        Address address2 = new Address("江西省","南昌市","阳明路","330004");
        map.put("address2", address2);
        Address address3 = new Address("陕西省","西安市","长安南路","710114");
        map.put("address3", address3);
        String jsonText = JSON.toJSONString(map, true);
        System.out.println("map2Json()方法：jsonText=="+jsonText);
        //输出结果：jsonText=={
  
  "address1":{
  
  "city":"深圳市","post":"580053","province":"广东省","street":"科苑南路"},"address2":{
  
  "city":"南昌市","post":"330004","province":"江西省","street":"阳明路"},"address3":{
  
  "city":"西安市","post":"710114","province":"陕西省","street":"长安南路"}}
    }

    /** * json转map */
    @Test
    public void json2Map(){
        String text = "{\"age\":12,\"id\":\"001\",\"name\":\"tom\"}";
        Map<String,Object> map = JSON.parseObject(text);
        System.out.println("json2Map()方法：map=="+map);
        //输出结果：{
  
  "name":"tom","id":"001","age":12}
        Set<String> set = map.keySet();
        for(String key : set){
            System.out.println(key+"--->"+map.get(key));
        }
    }
}

复制

技巧

package com.wanggs.com.wanggs.json.fastjson;

import com.alibaba.fastjson.JSON;

/** * Created by wanggs on 2017/7/27. */
public class CustomText { 
   

    /** * touser : OPENID * msgtype : text * text : {"content":"Hello World"} */
//{"msgtype":"text","text":{"content":"Hello World"},"touser":"OPENID"}
    private String touser;
    private String msgtype;
    private TextBean text;

    public static class TextBean { 
   
        /** * content : Hello World */

        private String content;

        public String getContent() {
            return content;
        }

        public void setContent(String content) {
            this.content = content;
        }
    }
    public String getTouser() {
        return touser;
    }

    public void setTouser(String touser) {
        this.touser = touser;
    }

    public String getMsgtype() {
        return msgtype;
    }

    public void setMsgtype(String msgtype) {
        this.msgtype = msgtype;
    }

    public TextBean getText() {
        return text;
    }

    public void setText(TextBean text) {
        this.text = text;
    }
}

class Test{
    public static void main(String[] args) {
        CustomText customText = new CustomText();
        customText.setTouser("OPENID");
        customText.setMsgtype("text");
        CustomText.TextBean textBean =  new CustomText.TextBean();
        textBean.setContent("Hello World");
        customText.setText(textBean);

        String json = JSON.toJSONString(customText);
        System.out.println(json);
        //{"msgtype":"text","text":{"content":"Hello World"},"touser":"OPENID"}
    }
    /** * { "touser":"OPENID", "msgtype":"text", "text": { "content":"Hello World" } } */
    }

复制

归纳六种方式json转map

package com.wanggs.com.wanggs.json.fastjson;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;

import java.util.Map;
import java.util.Set;

/** * Created by wanggs on 2017/7/27. */
public class FastJsonTest1 {
    public static void main(String[] args) {
        String str = "{\"0\":\"zhangsan\",\"1\":\"lisi\",\"2\":\"wangwu\",\"3\":\"maliu\"}";
        //第一种方式
        Map maps = (Map)JSON.parse(str);
        System.out.println("这个是用JSON类来解析JSON字符串!!!");
        for (Object map : maps.entrySet()){
            System.out.println(((Map.Entry)map).getKey()+" " + ((Map.Entry)map).getValue());
        }
        //第二种方式
        Map mapTypes = JSON.parseObject(str);
        System.out.println("这个是用JSON类的parseObject来解析JSON字符串!!!");
        for (Object obj : mapTypes.keySet()){
            System.out.println("key为："+obj+"值为："+mapTypes.get(obj));
        }
        //第三种方式
        Map mapType = JSON.parseObject(str,Map.class);
        System.out.println("这个是用JSON类,指定解析类型，来解析JSON字符串!!!");
        for (Object obj : mapType.keySet()){
            System.out.println("key为："+obj+"值为："+mapType.get(obj));
        }
        //第四种方式
        /** * JSONObject是Map接口的一个实现类 */
        Map json = (Map) JSONObject.parse(str);
        System.out.println("这个是用JSONObject类的parse方法来解析JSON字符串!!!");
        for (Object map : json.entrySet()){
            System.out.println(((Map.Entry)map).getKey()+" "+((Map.Entry)map).getValue());
        }
        //第五种方式
        /** * JSONObject是Map接口的一个实现类 */
        JSONObject jsonObject = JSONObject.parseObject(str);
        System.out.println("这个是用JSONObject的parseObject方法来解析JSON字符串!!!");
        for (Object map : json.entrySet()){
            System.out.println(((Map.Entry)map).getKey()+" "+((Map.Entry)map).getValue());
        }
        //第六种方式
        /** * JSONObject是Map接口的一个实现类 */
        Map mapObj = JSONObject.parseObject(str,Map.class);
        System.out.println("这个是用JSONObject的parseObject方法并执行返回类型来解析JSON字符串!!!");
        for (Object map: json.entrySet()){
            System.out.println(((Map.Entry)map).getKey()+" "+((Map.Entry)map).getValue());
        }
        String strArr = "{ 
   {\"0\":\"zhangsan\",\"1\":\"lisi\",\"2\":\"wangwu\",\"3\":\"maliu\"}," +
                "{\"00\":\"zhangsan\",\"11\":\"lisi\",\"22\":\"wangwu\",\"33\":\"maliu\"}}";
        // JSONArray.parse()
        System.out.println(json);
    }
}

复制

package com.wanggs.com.wanggs.json.fastjson;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;

import java.util.*;

/** * Created by wanggs on 2017/7/27. */
public class FastJsonTest {
    public static void main(String[] args) {

        String json = "[{\"id\":1,\"type\":\"cycle\",\"attribute\":{\"center\":\"(10.4, 123.345)\", \"radius\":67.4}},{\"id\":2,\"type\":\"polygon\",\"attribute\":[{\"vertex\":\"(10.4, 133.345)\"}, {\"vertex\":\"(10.4, 143.345)\"}]}]";

        JSONArray array = JSON.parseArray(json);

        System.out.println(array.getJSONObject(0).getJSONObject("attribute").get("center"));

        System.out.println(array.getJSONObject(1).getJSONArray("attribute").getJSONObject(1).get("vertex"));

       // 输出结果为: (10.4, 123.345) (10.4, 143.345)
    }
}

复制

方法总结

java和js中JSONObject,JSONArray,Map,String之间转换——持续更新中

4.JSONObject、JSONArray，Map转String JSONObject——String： System.out.println(myJsonObject);//可直接输出JSONObject的内容 myJsonObject.toString(); JSONArray——String： System.out.println(myJsonArray);//可直接输出myJsonArray的内容 myJsonArray.toString(); Map——String: System.out.println(map);//可直接输出map的内容 map.toString(); 5.JSONObject转JSONArray

JSONObject myJson = JSONObject.fromObject(jsonString);

Map m = myJson;

7.JSONArray转JSONObject for(int i=0 ; i < myJsonArray.length() ;i++) { //获取每一个JsonObject对象 JSONObject myjObject = myJsonArray.getJSONObject(i);

}

8.JSONArray转Map 9.Map转JSONObject JSONObject json = JSONObject.fromObject( map ); 10.Map转JSONArray JSONArray.fromObject(map); 11.List转JSONArray JSONArray jsonArray2 = JSONArray.fromObject( list );

发布者：全栈程序员栈长，转载请注明出处：https://javaforall.cn/133978.html原文链接：https://javaforall.cn