写一个toJSON方法将Map<String,String>对象转换成JSON字符串

/**

 * 

 * @author gavin

 *

 */

public class Gson{

public static String toJson(Map<String,String> map){

   Set<String> keys = map.keySet();

   String key = "";

   String value = "";

   StringBuffer jsonBuffer = new StringBuffer();

   jsonBuffer.append("{");    

   for(Iterator<String> it = keys.iterator();it.hasNext();){

       key =  (String)it.next();

       value = map.get(key);

       jsonBuffer.append(key+":"+value);

       if(it.hasNext()){

            jsonBuffer.append(",");

       }

   }

   jsonBuffer.append("}");

   return jsonBuffer.toString();

}

public static String toJson2(Map<String,String> map){

Set<Map.Entry<String, String>> entrys = map.entrySet();

Map.Entry<String, String> entry = null;

   String key = "";

   String value = "";

   StringBuffer jsonBuffer = new StringBuffer();

   jsonBuffer.append("{");    

   for(Iterator<Map.Entry<String, String>> it = entrys.iterator();it.hasNext();){

    entry =  (Map.Entry<String, String>)it.next();

    key = entry.getKey();

       value = entry.getValue();

       jsonBuffer.append(key+":"+value);

       if(it.hasNext()){

            jsonBuffer.append(",");

       }

   }

   jsonBuffer.append("}");

   return jsonBuffer.toString();

}

public static void main(String args[]){

Map<String,String> map = new TreeMap<String,String>();

map.put("1", "zhangyi");

map.put("2", "zhanger");

map.put("3", "zhangsan");

map.put("4", "zhangsi");

map.put("5", "zhangwu");

System.out.println(toJson(map));

System.out.println(toJson2(map));

}

}

运行结果：

{1:zhangyi,2:zhanger,3:zhangsan,4:zhangsi,5:zhangwu}

{1:zhangyi,2:zhanger,3:zhangsan,4:zhangsi,5:zhangwu}