android中Http访问时 connection.getResponseCode()不被执行

问题：用 android 4.4 写android访问http时，到connection.getResponseCode() 就不被执行，也不报错。如下面红色字体：

public static String getJsonContent(String url_path ,String encode){
		
		String jsonString = "";
		try {
			URL url = new URL(url_path);			
			HttpURLConnection connection = (HttpURLConnection)url.openConnection();
			
			connection.setConnectTimeout(3000);
			connection.setRequestMethod("GET");
			connection.setDoInput(true);  //从服务器获得数据
			
			int responseCode = connection.getResponseCode(); 			
			
			if (200 == responseCode) {
				jsonString = changeInputStream(connection.getInputStream(),encode);
				
			}
			
		
			
		} catch (Exception e) {
			// TODO: handle exception
		}
		
	//
		return jsonString;
	}

	private static String changeInputStream(InputStream inputStream , String encode) throws IOException {
		// TODO Auto-generated method stub
		String  jsonString = null;
		
		ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
		byte[] data = new byte[1024];
		int len = 0;
		while((len=inputStream.read(data))!=-1){
			outputStream.write(data, 0, len);
		}
		
		jsonString = new String(outputStream.toByteArray(), encode);

		inputStream.close();
		
		
		return jsonString;
	}

此段代码直接在java 工程里是可以访问http的，并且用浏览器直接访问 urp_path = http://192.168.0.102:8080/json_Project/servlet/JsonAction?action_flag=person 也是有相应的，证明url地址是对的。

解决方法：

原因：访问HTTP的请求没有放在单独线程而是放在主线程了。

解决方法，把http的请求单独放在一个新线程中，或者在调用此Http访问的Activity的onCreat()方法内加:closeStrictMode().

public static void closeStrictMode() {
StrictMode.setThreadPolicy(new StrictMode.ThreadPolicy.Builder()
.detectAll().penaltyLog().build());
}

参考文章:http://hb.qq.com/a/20110914/000054.htm