fastjson的JSONArray和JSONObject

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"}]    }}

---

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;    }}

---

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"}]}    }}

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    }}

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;    }}

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));        }    }}

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"     }     }     */    }

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);    }}

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)    }}

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 );