Gson 例子

更多请读:http://blog.csdn.net/lk_blog/article/details/7685169

package JSON;

import java.lang.reflect.Type;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;

public class TestJSON {
	public class User {
		private String username;
		private int userId;
		public String getUsername() {
			return username;
		}
		public void setUsername(String username) {
			this.username = username;
		}
		public int getUserId() {
			return userId;
		}
		public void setUserId(int userId) {
			this.userId = userId;
		}
	}
	/**
	 * @param args
	 */
	public static void main(String[] args) {
		Gson gson = new Gson();
		Map map = new HashMap();
		map.put("a", "b");
		map.put("c", 5);
		System.out.println(gson.toJson(map));

		String jsonData = "{\"username\":\"arthinking\",\"userId\":123}";
		User user = new Gson().fromJson(jsonData, User.class);
		System.out.println(user.getUsername());
		System.out.println(user.getUserId());
		
		
	}

}

.

/**版本必须是:gson-2.2.4.jar及以上版本**/		
public static void testMapString() {  
			GsonBuilder gb = new GsonBuilder();
		       Gson gson = gb.create();
	        Map map = new HashMap();  
	        map.put("a" , "A");  
	        map.put("b" , 999);  
	        map.put("7" , 999);  
	        String json = gson.toJson(map);  
	        System.out.println(json);  
	          
	        Map map2 = gson.fromJson(json , HashMap.class);  
	        for(Object each : map2.entrySet()) {  
	            System.out.println(each);  
	        }  
	    }