六個架包（666）

首先我們系統中要用到JSON解析，所以要引入這六個架包。飽飽

不引入這六個架包的話，使用JSONObject.fromObject ?和?SONObject.toBean會報錯，而且有的時候編譯器不會告訴你是架包缺少的錯誤哦！

JSON 對象? 與? JAVA對象的轉換

JSONObject? ?json = JSONObject.fromObject(String);//java轉json

JSONObject.toBean()//json轉java

（1）java對象轉json對象。

? ? ? ? ? ? ? ? ——HashMap轉為JSON對象：JSONObject.fromObject()

? ? ? ? ? json對象又再次轉換成java對象

? ? ? ? ? ? ? ? ?——JSON轉為Map<String,String>：JSON強制轉換

栗子1

public class JSONTest {public static void main(String[] args){HashMap<String,String> map=new HashMap<String,String>();map.put("A", "B");//map={A=B}JSONObject json = JSONObject.fromObject(map);//json={"A":"B"}System.out.println(json.toString());//{"A":"B"}//再將json強轉成mapMap<String,String> map2=(Map<String,String>)json;//{"A":"B"}System.out.println(map2.toString());} }

忽然發現兩件事：

一件事：HashMap中key值相同的話，前一個會被后一個覆蓋。（原諒我太渣，現在才知道）

第二件事：相比于有道筆記，飽飽更愛寫CSDN啊！

public class JSONTest {public static void main(String[] args){HashMap<String,String> map=new HashMap<String,String>();map.put("A", "B");//map={A=B}map.put("A", "C");//map={A=C}JSONObject json = JSONObject.fromObject(map);//json={"A":"C"}System.out.println(json.toString());//{"A":"C"}//再將json強轉成mapMap<String,String> map2=(Map<String,String>)json;//{"A":"C"}System.out.println(map2.toString());} }

栗子2

public class JSONTest {public static void main(String[] args){HashMap<String,String> map=new HashMap<String,String>();map.put("A", "B");//map={A=B}map.put("C", "D");//map={A=B, C=D}JSONObject json = JSONObject.fromObject(map);//json={"A":"B","C":"D"}System.out.println(json.toString());//再將json強轉成mapMap<String,String> map2=(Map<String,String>)json;//{"A":"B","C":"D"}System.out.println(map2.toString());} }

（2）java對象轉json對象。

? ? ? ? ? ? ? ? ——String轉為JSON對象：JSONObject.fromObject()

? ? ? ? ? json對象又再次轉換成java對象

? ? ? ? ? ? ? ? ?——JSON轉為Map<String,Object>：JSON強制轉換

mapString = {"errmsg":"ok","ErrorCode":0,"messageId":"f5d4566c4c833152b3feb42a8092ee6c","invaliduser":"","forbiddenUserId":"","resJson":{"errmsg":"ok","ErrorCode":0,"messageId":"f5d4566c4c833152b3feb42a8092ee6c","invaliduser":"","forbiddenUserId":""} } public class JSONTest {public static void main(String[] args){//將string類型的map數據轉換為json的數據格式，在將json的數據格式的轉換成java的 Map<String,Object>的數據類型String mapString = "{\"errmsg\":\"ok\",\"ErrorCode\":0,\"messageId\":\"f5d4566c4c833152b3feb42a8092ee6c\",\"invaliduser\":\"\",\"forbiddenUserId\":\"\",\"resJson\":{\"errmsg\":\"ok\",\"ErrorCode\":0,\"messageId\":\"f5d4566c4c833152b3feb42a8092ee6c\",\"invaliduser\":\"\",\"forbiddenUserId\":\"\"}}";//mapString={"errmsg":"ok","ErrorCode":0,"messageId":"f5d4566c4c833152b3feb42a8092ee6c","invaliduser":"","forbiddenUserId":"","resJson":{"errmsg":"ok","ErrorCode":0,"messageId":"f5d4566c4c833152b3feb42a8092ee6c","invaliduser":"","forbiddenUserId":""}}JSONObject json = JSONObject.fromObject(mapString);//json ={"errmsg":"ok","ErrorCode":0,"messageId":"f5d4566c4c833152b3feb42a8092ee6c","invaliduser":"","forbiddenUserId":"","resJson":{"errmsg":"ok","ErrorCode":0,"messageId":"f5d4566c4c833152b3feb42a8092ee6c","invaliduser":"","forbiddenUserId":""}}Map<String, Object> map = (Map<String, Object>)json;//map ={"errmsg":"ok","ErrorCode":0,"messageId":"f5d4566c4c833152b3feb42a8092ee6c","invaliduser":"","forbiddenUserId":"","resJson":{"errmsg":"ok","ErrorCode":0,"messageId":"f5d4566c4c833152b3feb42a8092ee6c","invaliduser":"","forbiddenUserId":""}}System.out.println("-----map:---"+map.toString());} }

（3）java對象轉json對象。

? ? ? ? ? ? ? ? ?——String轉為JSON對象：JSONObject.fromObject()

? ? ? ? ? json對象又再次轉換成java對象

? ? ? ? ? ? ? ? ? ——JSON轉為Student對象：JSONObject.toBean()

public class JSONTest {public static void main(String[] args){String mapString = "{id:'211415034',name:'徐妍',age:'24'}";Student student = new Student();JSONObject json = JSONObject.fromObject(mapString);//json={"id":"211415034","name":"徐妍","age":"24"}student = (Student)JSONObject.toBean(json, Student.class);//曾經的學號：211415034 姓名：徐妍 年齡：24//JSONObject.toBean() 方法意為：從JSONObject 對象轉換為 JAVA 對象。System.out.println(student);} } public class Student {private int id;private String name;private int age;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 int getAge(){return age;}public void setAge(int age){this.age = age;} public String toString(){return "曾經的學號："+this.id+" 姓名："+this.name+" 年齡："+this.age;} }

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總結

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