Android中HttpURLConnection与HttpClient的使用与封装

Android中HttpURLConnection与HttpClient的使用与封装

1. HttpURLConnection的使用
   HttpURLConnection是Android中自带的一个HTTP客户端库，可以轻松的使用HTTP请求。使用HttpURLConnection发送请求的步骤如下：

（1）创建URL对象
URL url = new URL("http://www.example.com");
（2）创建HttpURLConnection对象
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
（3）设置请求方式
conn.setRequestMethod("GET");
（4）设置连接超时时间
conn.setConnectTimeout(5000);
（5）设置读取超时时间
conn.setReadTimeout(5000);
（6）连接服务器
conn.connect();
（7）获取响应码
int responseCode = conn.getResponseCode();
（8）获取输入流，读取服务器返回的数据
InputStream inputStream = conn.getInputStream();
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
String line;
while ((line = bufferedReader.readLine()) != null) {
Log.d("TAG", line);
}
bufferedReader.close();
inputStream.close();
（9）断开连接
conn.disconnect();

1. HttpClient的使用
   HttpClient是Apache提供的一个HTTP客户端库，可以轻松地使用HTTP请求。使用HttpClient发送请求的步骤如下：

（1）创建HttpClient对象
HttpClient httpClient = new DefaultHttpClient();
（2）根据URL创建HttpGet或HttpPost对象
HttpGet httpGet = new HttpGet("http://www.example.com");
HttpPost httpPost = new HttpPost("http://www.example.com");
（3）设置参数（如果有）
List<NameValuePair> params = new ArrayList<>();
params.add(new BasicNameValuePair("username", "admin"));
httpPost.setEntity(new UrlEncodedFormEntity(params, "UTF-8"));
（4）执行请求，获取HttpResponse对象
HttpResponse httpResponse = httpClient.execute(httpGet);
（5）获取响应码
int responseCode = httpResponse.getStatusLine().getStatusCode();
（6）获取数据流，读取服务器返回的数据
InputStream inputStream = httpResponse.getEntity().getContent();
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
String line;
while ((line = bufferedReader.readLine()) != null) {
Log.d("TAG", line);
}
bufferedReader.close();
inputStream.close();
（7）释放资源
httpClient.getConnectionManager().shutdown();

1. 封装Http请求
   封装Http请求可以减少代码重复，提高代码复用性。可以将HttpURLConnection和HttpClient封装成一个类，提供公共方法供外部调用。

（1）封装HttpURLConnection
```
public class HttpHelper {

        public static String requestGet(String URLAddress) throws IOException {
            StringBuilder stringBuilder = new StringBuilder();

            URL url = new URL(URLAddress);
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            conn.setRequestMethod("GET");
            conn.setConnectTimeout(5000);
            conn.setReadTimeout(5000);

            if (conn.getResponseCode() == HttpURLConnection.HTTP_OK) {
                InputStream inputStream = conn.getInputStream();
                BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
                String line;
                while ((line = bufferedReader.readLine()) != null) {
                    stringBuilder.append(line).append("\n");
                }
                bufferedReader.close();
                inputStream.close();
            }

            conn.disconnect();

            return stringBuilder.toString();
        }
    }
    ```

（2）封装HttpClient
```
public class HttpHelper {

        public static String requestGet(String urlAddress) throws IOException {
            StringBuilder stringBuilder = new StringBuilder();

            HttpClient httpClient = new DefaultHttpClient();
            HttpGet httpGet = new HttpGet(urlAddress);

            HttpResponse httpResponse = httpClient.execute(httpGet);

            if (httpResponse.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {
                InputStream inputStream = httpResponse.getEntity().getContent();
                BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
                String line;
                while ((line = bufferedReader.readLine()) != null) {
                    stringBuilder.append(line).append("\n");
                }
                bufferedReader.close();
                inputStream.close();
            }

            httpClient.getConnectionManager().shutdown();

            return stringBuilder.toString();
        }
    }
    ```

1. 示例说明
   （1）使用HttpURLConnection发送GET请求
   new Thread(new Runnable() {
@Override
public void run() {
try {
String result = HttpHelper.requestGet("http://www.example.com");
Log.d("TAG", result);
} catch (IOException e) {
e.printStackTrace();
}
}
}).start();
   （2）使用HttpClient发送GET请求
   new Thread(new Runnable() {
@Override
public void run() {
try {
String result = HttpHelper.requestGet("http://www.example.com");
Log.d("TAG", result);
} catch (IOException e) {
e.printStackTrace();
}
}
}).start();