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簡介:

在程序開發(fā)過程中，在參數(shù)傳遞，函數(shù)返回值等方面，越來越多的使用JSON。JSON(JavaScript Object Notation)是一種輕量級的數(shù)據(jù)交換格式，同時也易于機器解析和生成、易于理解、閱讀和撰寫，而且Json采用完全獨立于語言的文本格式，這使得Json成為理想的數(shù)據(jù)交換語言。

JSON建構(gòu)于兩種結(jié)構(gòu)：

“名稱/值”對的集合(A Collection of name/value pairs)，在不同的語言中，它被理解為對象(Object), 記錄(record), 結(jié)構(gòu)(struct), 字典(dictionary), 有趣列表(keyed list), 哈希表(hash table)或者關(guān)聯(lián)數(shù)組(associative array)。

JSONObject依賴：

最后一行需要保留，有兩個jdk版本的實現(xiàn)：json-lib-2.1-jdk13.jar和json-lib-2.1-jdk15.jar

net.sf.json-lib json-lib 2.4jdk15

使用net.sf.json需要導(dǎo)入的jar包

jar包下載：https://pan.baidu.com/s/1iZiXw55TPwIxYFQQCaR9Gw

JSONObject

創(chuàng)建JSONObject，添加屬性

//創(chuàng)建JSONObjectJSONObject json = new JSONObject();//添加屬性json.put("username", "張三");json.put("password", "123");//打印System.out.println(json); //增加屬性json.element("sex", "男");json.put("age", 18);System.out.println(json);

根據(jù)key返回輸出

System.out.println(json.get("sex"));

判斷輸出對象的類型

boolean isArray = json.isArray();boolean isEmpty = json.isEmpty();boolean isNullObject = json.isNullObject();System.out.println("是否數(shù)組："+isArray+", 是否空："+isEmpty+", 是否空為空對象："+isNullObject);

把JSONArray添加到JSONObject中

/把JSONArray添加到JSONObject中JSONArray jsonArray = new JSONArray();jsonArray.add(0, "張三");jsonArray.add(1, "123");//開始添加json.element("student", jsonArray);System.out.println(json);

全部代碼：

import net.sf.json.JSONArray;import net.sf.json.JSONObject; public class Json {public static void main(String[] args) {//創(chuàng)建JSONObjectJSONObject json = new JSONObject();//添加屬性json.put("username", "張三");json.put("password", "123");//打印System.out.println(json);//增加屬性json.element("sex", "男");json.put("age", 18);System.out.println(json);//根據(jù)key返回System.out.println(json.get("sex"));//判斷輸出對象的類型boolean isArray = json.isArray();boolean isEmpty = json.isEmpty();boolean isNullObject = json.isNullObject();System.out.println("是否數(shù)組："+isArray+", 是否空："+isEmpty+", 是否空為空對象："+isNullObject);System.out.println("=====");//把JSONArray添加到JSONObject中JSONArray jsonArray = new JSONArray();jsonArray.add(0, "張三");jsonArray.add(1, "123");//開始添加json.element("student", jsonArray);System.out.println(json);}}

運行結(jié)果：

JSONArray

創(chuàng)建JSONArray，添加屬性值

//創(chuàng)建JSONArrayJSONArray jsonArray = new JSONArray();//添加jsonArray.add(0, "張三");jsonArray.add(1, "123");jsonArray.element("男");System.

根據(jù)下標返回輸出

System.out.println(jsonArray.get(0));

根據(jù)下標設(shè)置新值，修改

jsonArray.set(0, "李四");System.out.println(jsonArray);把JSONObject放入到JSONArray中//把JSONObject放入到JSONArray中JSONObject jsonObject = new JSONObject();jsonObject.put("username", "張三");jsonObject.put("password", "123");jsonArray.add(jsonObject);System.

全部代碼：

import net.sf.json.JSONArray;import net.sf.json.JSONObject; public class Json {public static void main(String[] args) {//創(chuàng)建JSONArrayJSONArray jsonArray = new JSONArray();//添加jsonArray.add(0, "張三");jsonArray.add(1, "123");jsonArray.element("男");System.out.println(jsonArray);//根據(jù)下標返回輸出System.out.println(jsonArray.get(0));//根據(jù)下標設(shè)置新值，修改jsonArray.set(0, "李四");System.out.println(jsonArray);//把JSONObject放入到JSONArray中JSONObject jsonObject = new JSONObject();jsonObject.put("username", "張三");jsonObject.put("password", "123");jsonArray.add(jsonObject);System.out.println(jsonArray);//循環(huán)輸出for(int i = 0; i < jsonArray.size(); i++) {System.out.println(jsonArray.get(i));}}}

運行結(jié)果

JavaBean與json字符串互轉(zhuǎn)

student類：

public class Student {private String username;private String password;public String getUsername() {return username;}public void setUsername(String username) {this.username = username;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}public Student(String username, String password) {super();this.username = username;this.password = password;}public Student() {super();// TODO Auto-generated constructor stub}@Overridepublic String toString() {return "Student [username=" + username + ", password=" + password + "]";}}

定義對象，JavaBean對象轉(zhuǎn)json字符串

//定義對象Student stu = new Student("張三", "123456");//JavaBean對象轉(zhuǎn)json字符串JSONObject jsonObject = JSONObject.fromObject(stu);System.out.println(jsonObject);

json字符串轉(zhuǎn)為javaBean

//json字符串轉(zhuǎn)為javaBean//定義json字符串String jsondata = "{"username":"李四", "password":"123"}";//轉(zhuǎn)為json對象JSONObject json = JSONObject.fromObject(jsondata);//轉(zhuǎn)為JavaBean對象Student stu2 = (Student)JSONObject.toBean(json, Student.class);System.out.println(stu2.toString());

全部代碼：

import net.sf.json.JSONObject; public class Json {public static void main(String[] args) {//定義對象Student stu = new Student("張三", "123456");//JavaBean對象轉(zhuǎn)json字符串JSONObject jsonObject = JSONObject.fromObject(stu);System.out.println(jsonObject);//json字符串轉(zhuǎn)為javaBean//定義json字符串String jsondata = "{"username":"李四", "password":"123"}";//轉(zhuǎn)為json對象JSONObject json = JSONObject.fromObject(jsondata);//轉(zhuǎn)為JavaBean對象Student stu2 = (Student)JSONObject.toBean(json, Student.class);System.out.println(stu2.toString());}}

輸出結(jié)果：

List與json字符串互轉(zhuǎn)

先定義list集合，list轉(zhuǎn)json字符串

//定義list集合List list = new ArrayList();list.add(new Student("張三", "123"));list.add(new Student("李四", "456"));//list轉(zhuǎn)json字符串JSONArray jsonArray = JSONArray.fromObject(list);System.out.println(jsonArray);

json字符串轉(zhuǎn)list

//json字符串轉(zhuǎn)listList list2 = new ArrayList();String jsondata = "[{"password":"123","username":"張三"},{"password":"456","username":"李四"}]";JSONArray jsonArray1 = JSONArray.fromObject(jsondata);for(int i = 0; i < jsonArray1.size(); i++) {JSONObject jsonObject2 = jsonArray1.getJSONObject(i);Student stu2 = (Student)JSONObject.toBean(jsonObject2, Student.class);list2.add(stu2);}System.out.println(list2);

全部代碼

import java.util.ArrayList;import java.util.List; import net.sf.json.JSONArray;import net.sf.json.JSONObject; public class Json {public static void main(String[] args) {//定義list集合List list = new ArrayList();list.add(new Student("張三", "123"));list.add(new Student("李四", "456"));//list轉(zhuǎn)json字符串JSONArray jsonArray = JSONArray.fromObject(list);System.out.println(jsonArray);//json字符串轉(zhuǎn)listList list2 = new ArrayList();String jsondata = "[{"password":"123","username":"張三"},{"password":"456","username":"李四"}]";JSONArray jsonArray1 = JSONArray.fromObject(jsondata);for(int i = 0; i < jsonArray1.size(); i++) {JSONObject jsonObject2 = jsonArray1.getJSONObject(i);Student stu2 = (Student)JSONObject.toBean(jsonObject2, Student.class);list2.add(stu2);}System.out.println(list2);}}

運行結(jié)果

Map與json字符串互轉(zhuǎn)

定義map集合，Map轉(zhuǎn)json字符串

//定義map集合Map map = new HashMap();map.put("1", new Student("張三", "123"));map.put("2", new Student("李四", "456"));//Map轉(zhuǎn)json字符串JSONObject jsonMap = JSONObject.fromObject(map);System.out.println(jsonMap);

定義字符串map集合，map集合字符串轉(zhuǎn)為map

//定義字符串map集合String jsondata = "{"1":{"password":"123","username":"張三"},"2":{"password":"456","username":"李四"}}";//map集合字符串轉(zhuǎn)為mapMap map2 = (Map)JSONObject.fromObject(jsondata);Set set = map2.keySet();//定義迭代器，迭代輸出Iterator ite = set.iterator();while(ite.hasNext()) {//取出一個字符串對象String key = (String)ite.next();//轉(zhuǎn)為json格式JSONObject jsonObject = JSONObject.fromObject(map2.get(key));//轉(zhuǎn)為對象Student stu = (Student)JSONObject.toBean(jsonObject, Student.class);System.out.println(key+" "+stu);}

全部代碼

import java.util.HashMap;import java.util.Iterator;import java.util.Map;import java.util.Set; import net.sf.json.JSONObject; public class Json {public static void main(String[] args) {//定義map集合Map map = new HashMap();map.put("1", new Student("張三", "123"));map.put("2", new Student("李四", "456"));//Map轉(zhuǎn)json字符串JSONObject jsonMap = JSONObject.fromObject(map);System.out.println(jsonMap);//定義字符串map集合String jsondata = "{"1":{"password":"123","username":"張三"},"2":{"password":"456","username":"李四"}}";//map集合字符串轉(zhuǎn)為mapMap map2 = (Map)JSONObject.fromObject(jsondata);Set set = map2.keySet();//定義迭代器，迭代輸出Iterator ite = set.iterator();while(ite.hasNext()) {//取出一個字符串對象String key = (String)ite.next();//轉(zhuǎn)為json格式JSONObject jsonObject = JSONObject.fromObject(map2.get(key));//轉(zhuǎn)為對象Student stu = (Student)JSONObject.toBean(jsonObject, Student.class);System.out.println(key+" "+stu);}}}

運行結(jié)果:

SONArray與List互轉(zhuǎn)

定義list集合，List轉(zhuǎn)型JSONArray

//定義list集合List list = new ArrayList();list.add(new Student("張三", "123"));list.add(new Student("李四", "456"));//List轉(zhuǎn)型JSONArrayJSONArray jsonArray = JSONArray.fromObject(list);System.out.println(jsonArray.toString());

JSONArray轉(zhuǎn)型List，JSONArray是用的上面的那個jsonArray變量

//JSONArray轉(zhuǎn)型ListList list2 = JSONArray.toList(jsonArray, new Student(), new JsonConfig());Iterator ite = list2.iterator();while(ite.hasNext()) {Student stu = ite.next();System.out.println(stu);}

全部代碼

import java.util.ArrayList;import java.util.Iterator;import java.util.List; import net.sf.json.JSONArray;import net.sf.json.JsonConfig; public class Json {public static void main(String[] args) {//定義list集合List list = new ArrayList();list.add(new Student("張三", "123"));list.add(new Student("李四", "456"));//List轉(zhuǎn)型JSONArrayJSONArray jsonArray = JSONArray.fromObject(list);System.out.println(jsonArray.toString());//JSONArray轉(zhuǎn)型ListList list2 = JSONArray.toList(jsonArray, new Student(), new JsonConfig());Iterator ite = list2.iterator();while(ite.hasNext()) {Student stu = ite.next();System.out.println(stu);}}}

運行結(jié)果

JSONArray與數(shù)組互轉(zhuǎn)

定義數(shù)組，數(shù)組轉(zhuǎn)JSONArray

//定義數(shù)組boolean[] boolArray = {true, false, true};//java數(shù)組轉(zhuǎn)JSONArrayJSONArray jsonArray = JSONArray.fromObject(boolArray);System.out.println(jsonArray.toString());

JSONArray轉(zhuǎn)java數(shù)組

//JSONArray轉(zhuǎn)java數(shù)組Object obj[] = jsonArray.toArray();for(Object o : obj) {System.out.print(o+"");}

全部代碼

import net.sf.json.JSONArray; public class Json {public static void main(String[] args) {//定義數(shù)組boolean[] boolArray = {true, false, true};//java數(shù)組轉(zhuǎn)JSONArrayJSONArray jsonArray = JSONArray.fromObject(boolArray);System.out.println(jsonArray.toString());//JSONArray轉(zhuǎn)java數(shù)組Object obj[] = jsonArray.toArray();for(Object o : obj) {System.out.print(o+"");}}}

運行結(jié)果：

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本文鏈接：https://blog.csdn.net/qq_40205116/article/details/102921564

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