JSON in JAVA 的簡單程式範例

SON(JavaScript Object Notation)
因為格式簡單且用純文字方便讀取
支援了各式各樣的語言(都有相關的函式可用)
在資料處理交換上是很方便的格式
可以在這邊看到詳細介紹

以下的程式簡單地示範了JAVA中JSON的應用
其中包含了一個 PeopleBean 及主要的程式碼

PeopleBean：

package demo.json;
  public class PeopleBean {
    private String name;
    private int age;
    private boolean gender;


  public PeopleBean(String name, int age, boolean gender) {
   setPeopleBean(name, age, gender);
  }
   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 boolean getGender() {
   return gender;
   }
  public void setGender(boolean gender) {
   this.gender = gender;
  }
   /***************************************************************/
   public void setPeopleBean(String name, int age, boolean gender) {
    setName(name);
    setAge(age);
    setGender(gender);
   }
}

主程式：

package demo.json;


import java.util.HashMap;
import java.util.Map;


import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;


public class JsonDemo {


 public static void main(String[] args) throws JSONException {

 
  // 利用bean來產生一個對應的JSONObject
  PeopleBean Mary = new PeopleBean("Mary", 20, false);
  JSONObject jsonObjectMary = new JSONObject(Mary);
  System.out.println("1: " + jsonObjectMary);
 
 
  // 利用map的對照來產生JSONObject
  Map map = new HashMap();
  map.put("name", "Jacky");
  map.put("age", 30);
  map.put("gender", true);
  JSONObject jsonObjectJacky = new JSONObject(map);
  System.out.println("2: " + jsonObjectJacky);

 
  // 每個JSONObject都能利用JSONObject.put(key, value)來增加屬性
  jsonObjectJacky.put("height", 180);
  System.out.println("3: " + jsonObjectJacky);

 
  // 利用 JSON 的字串產生 JSONObject
  String jackyJsonString = jsonObjectJacky.toString();
  JSONObject jsonObjectJackyFromString = new JSONObject(jackyJsonString);
  // JSONObject.get(key) 可取得 JSONObject中對應的值
  // 找不到的話會丟出 org.json.JSONException如下面註解掉那行
  System.out.println("4: " + jsonObjectJackyFromString.get("name"));
  // System.out.println(jsonObjectJackyFromString.get("weight"));

 
  // 由JSONObject.names()取回names的JSONArray
  JSONArray jsonArrayNames = jsonObjectJacky.names();
  System.out.println("5: " + jsonArrayNames);
 
 
  // JSONArray可藉由JSONArray.put(value)來增加Array中的值
  jsonArrayNames.put("weight");
  System.out.println("6: " + jsonArrayNames);


 }
}

result:

1: {"gender":false,"age":20,"name":"Mary"}
2: {"gender":true,"age":30,"name":"Jacky"}
3: {"gender":true,"age":30,"height":180,"name":"Jacky"}
4: Jacky
5: ["gender","age","height","name"]
6: ["gender","age","height","name","weight"]

出處
http://werdna1222coldcodes.blogspot.com/2009/01/json-in-java.html