fastjson的JSONArray和JSONObject
阿新 • • 發佈：2018-12-31
什麼是JSON?
JSON(JavaScript Object Notation) 是一種輕量級的資料交換格式。 易於人閱讀和編寫。同時也易於機器解析和生成。 它基於javascript Programming Language, Standard ECMA-262 3rd Edition - December 1999的一個子集。 JSON採用完全獨立於語言的文字格式，但是也使用了類似於C語言家族的習慣（包括C, C++, C#, Java, JavaScript, Perl, Python等）。 這些特性使JSON成為理想的資料交換語言。
現在我們就來研究一下fastJson。
Fastjson是國內著名的電子商務網際網路公司阿里巴巴內部開發的用於java後臺處理json格式資料的一個工具包，包括“序列化”和“反序列化”兩部分，它具備如下特徵
1. 速度最快，測試表明，fastjson具有極快的效能，超越任其他的java json parser。包括自稱最快的jackson。
2. 功能強大，完全支援java bean、集合、Map、日期、Enum，支援範型，支援自省。
3. 無依賴，能夠直接執行在Java SE 5.0以上版本
4. 支援Android。
JSONObject 與JSONArray
- JSONObject
json物件，就是一個鍵對應一個值，使用的是大括號{ }，如：{key:value}
- JSONArray
json陣列，使用中括號[ ],只不過數組裡面的項也是json鍵值對格式的
Json物件中是新增的鍵值對,JSONArray中新增的是Json物件
例子
/**
* Created by wanggs on 2017/7/27.
*/
public class JsonTest {
public static void main(String[] args) {
// Json物件中是新增的鍵值對,JSONArray中新增的是Json物件 先來個官方例子
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);
// 輸出: {"id":0,"name":"admin","users":[{"id":1,"name":"guest"},{"id":2,"name":"root"}]}
}
}
下面給出fastJson處理json資料格式的程式碼樣例：
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);
// 輸出結果: {"age":12,"id":"001","name":"tom"}
}
/**
* 反序列為Json物件
*/
@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());
// 輸出結果為: parseBeanObject()方法：people==001,tom,12
}
/**
* 將javaBean轉化為json物件
*/
@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);
// 輸出結果: bean2Json()方法：jsonObject=={"name":"jack","id":"002","age":23}
}
/**
* 全序列化 直接把java bean序列化為json文字之後，能夠按照原來的型別反序列化回來。支援全序列化，需要開啟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);
// 輸出結果：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());
// 輸出結果：userObj==testFastJson001,maks,105
}
}附：javaBean類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 {
/**
* 陣列轉json字串
*/
@Test
public void array2Json() {
String[] arr = {"bill", "green", "maks", "jim"};
String jsonText = JSON.toJSONString(arr);
System.out.println("array2Json()方法：jsonText==" + jsonText);
// 輸出結果：jsonText==["bill","green","maks","jim"]
}
/**
* json格式字串轉陣列
*/
@Test
public void json2Array() {
String jsonText = "[\"bill\",\"green\",\"maks\",\"jim\"]";
JSONArray jsonArray = JSON.parseArray(jsonText);
System.out.println("json2Array()方法：jsonArray==" + jsonArray);
// 輸出結果：jsonArray==["bill","green","maks","jim"]
}
/**
* 陣列轉json格式字串
*/
@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);
//輸出結果：array2Json2()方法：jsonText==[{"age":12,"id":"001","name":"tom"},{"age":23,"id":"002","name":"jack"},{"age":22,"id":"003","name":"mair"}]
}
/**
* json格式字串轉陣列
*/
@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);
// 輸出結果：json2Array2()方法：jsonArr==[{"name":"tom","id":"001","age":12},{"name":"jack","id":"002","age":23},{"name":"mair","id":"003","age":22}]
}
/**
* list集合轉json格式字串
*/
@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);
// 輸出的結果為: [{"age":12,"id":"001","name":"tom"},{"age":23,"id":"002","name":"jack"},{"age":22,"id":"003","name":"mair"}]
}
/**
* map轉json格式字串
*/
@Test
public void map2Json() {
Map map = new HashMap();
Address address1 = new Address("廣東省","深圳市","科苑南路","580053");
map.put("address1", address1);
Address address2 = new Address("江西省","南昌市","陽明路","330004");
map.put("address2", address2);
Address address3 = new Address("陝西省","西安市","長安南路","710114");
map.put("address3", address3);
String jsonText = JSON.toJSONString(map, true);
System.out.println("map2Json()方法：jsonText=="+jsonText);
//輸出結果：jsonText=={"address1":{"city":"深圳市","post":"580053","province":"廣東省","street":"科苑南路"},"address2":{"city":"南昌市","post":"330004","province":"江西省","street":"陽明路"},"address3":{"city":"西安市","post":"710114","province":"陝西省","street":"長安南路"}}
}
/**
* json轉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);
//輸出結果：{"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"
}
}
*/
}
歸納六種方式json轉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\"}";
//第一種方式
Map maps = (Map)JSON.parse(str);
System.out.println("這個是用JSON類來解析JSON字串!!!");
for (Object map : maps.entrySet()){
System.out.println(((Map.Entry)map).getKey()+" " + ((Map.Entry)map).getValue());
}
//第二種方式
Map mapTypes = JSON.parseObject(str);
System.out.println("這個是用JSON類的parseObject來解析JSON字串!!!");
for (Object obj : mapTypes.keySet()){
System.out.println("key為："+obj+"值為："+mapTypes.get(obj));
}
//第三種方式
Map mapType = JSON.parseObject(str,Map.class);
System.out.println("這個是用JSON類,指定解析型別，來解析JSON字串!!!");
for (Object obj : mapType.keySet()){
System.out.println("key為："+obj+"值為："+mapType.get(obj));
}
//第四種方式
/**
* JSONObject是Map介面的一個實現類
*/
Map json = (Map) JSONObject.parse(str);
System.out.println("這個是用JSONObject類的parse方法來解析JSON字串!!!");
for (Object map : json.entrySet()){
System.out.println(((Map.Entry)map).getKey()+" "+((Map.Entry)map).getValue());
}
//第五種方式
/**
* JSONObject是Map介面的一個實現類
*/
JSONObject jsonObject = JSONObject.parseObject(str);
System.out.println("這個是用JSONObject的parseObject方法來解析JSON字串!!!");
for (Object map : json.entrySet()){
System.out.println(((Map.Entry)map).getKey()+" "+((Map.Entry)map).getValue());
}
//第六種方式
/**
* JSONObject是Map介面的一個實現類
*/
Map mapObj = JSONObject.parseObject(str,Map.class);
System.out.println("這個是用JSONObject的parseObject方法並執行返回型別來解析JSON字串!!!");
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"));
// 輸出結果為: (10.4, 123.345) (10.4, 143.345)
}
}
方法總結
4.JSONObject、JSONArray，Map轉String
JSONObject——String：
System.out.println(myJsonObject);//可直接輸出JSONObject的內容
myJsonObject.toString();
JSONArray——String：
System.out.println(myJsonArray);//可直接輸出myJsonArray的內容
myJsonArray.toString();
Map——String:
System.out.println(map);//可直接輸出map的內容
map.toString();5.JSONObject轉JSONArray
JSONObject myJson = JSONObject.fromObject(jsonString);
Map m = myJson;
7.JSONArray轉JSONObject
for(int i=0 ; i < myJsonArray.length() ;i++)
{
//獲取每一個JsonObject物件
JSONObject myjObject = myJsonArray.getJSONObject(i);
}
8.JSONArray轉Map
9.Map轉JSONObject
JSONObject json = JSONObject.fromObject( map );10.Map轉JSONArray
JSONArray.fromObject(map);11.List轉JSONArray
JSONArray jsonArray2 = JSONArray.fromObject( list );