String、list、map轉換爲json

在web系統編程過程中經常用到Json，難免會進行數據之間的轉換，那麼如何將String、list、map數據轉換爲Json對象，以下爲轉換代碼（使用fastjson）：

import java.util.ArrayList;
import java.util.HashMap;
import com.alibaba.fastjson.JSONObject;
public class strToJson {
     //String轉json
     public static void main(String arg[]){
           String[] str = {"a","b","c","d","e"};
           JSONObject obj = new JSONObject();
           for(int i=0;i<str.length;i++){
                obj.put("letter",str[i]);
                System.out.println(obj.toString());
           }
     }
     
     //arraylist轉json
/*   public static void main(String[] args) {
           String[] str = {"a","b","c","d","e"};
           ArrayList list = new ArrayList();
           JSONObject obj = new JSONObject();
           for(int i = 0;i<str.length;i++){
                list.add(str[i]);
                obj.put("letter", list.get(i));
                System.out.println(obj.toString());
           }
     }*/
     
     //map轉json
/*   public static void main(String arg[]){
           String[][] str = {{"a","1"},{"b","2"},{"c","3"},{"d","4"}};
           JSONObject obj = new JSONObject();
           HashMap<String,String> map = new HashMap<String,String>();
           for(int i=0;i<str.length;i++){
                map.put(str[i][0], str[i][1]);
                System.out.println("這是map對象"+map);
                obj=(JSONObject) JSONObject.toJSON(map);
                System.out.println("這是json對象"+obj.toString());
           }
     }*/  
}