Android中使用HttpURLConnection和HttpClient发送Http请求

在android应用程序中，可以使用HttpURLConnection发送HTTP请求。详见如下实例

1、activity_main.xml布局文件

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" 
    android:orientation="vertical"
    >
	<Button 
	    android:id="@+id/send_request"
	    android:layout_width="match_parent"
	    android:layout_height="wrap_content"
	    android:text="发送请求"
	    />
	<ScrollView 
	    android:layout_width="match_parent"
	    android:layout_height="match_parent"
	    >
	    <TextView 
	        android:id="@+id/content"
	        android:layout_width="match_parent"
	        android:layout_height="wrap_content"
	        />
	    
	</ScrollView>
</LinearLayout>

2、MainActivity.java

package com.example.testhttp;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends Activity implements OnClickListener{
	
	private Button sendRequest;
	private TextView content;
	
	private static final int SHOW_RESPONSE_CONTENT = 0;
	
	private Handler handler = new Handler(){
		public void handleMessage(Message msg) {
			switch (msg.what) {
			case SHOW_RESPONSE_CONTENT:
				String response = (String) msg.obj;
				//显示到界面上
				content.setText(response);
				break;
			default:
				break;
			}
			
		};
	};
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		//获取发送按钮
		sendRequest = (Button) findViewById(R.id.send_request);
		//获取TextView
		content = (TextView) findViewById(R.id.content);
		sendRequest.setOnClickListener(this);
	}
	
	//重写点击方法
	@Override
	public void onClick(View view) {
		if(view.getId() == R.id.send_request){
			//如果是点击发送按钮，则处理Http请求--使用HttpURLConnection
			sendRequestWithHttpURLConnection();
		}
	}
	
	/**
	 * 使用HttpURLConnection发送请求
	 */
	public void sendRequestWithHttpURLConnection(){
		//新起一线程
		new Thread(new Runnable() {
			//处理逻辑
			@Override
			public void run() {
				HttpURLConnection connection = null;
				try {
					URL url = new URL("http://www.baidu.com");
					connection = (HttpURLConnection) url.openConnection();
					//设置参数
					//发送请求
					connection.setRequestMethod("GET");
					//连接超时时间
					connection.setConnectTimeout(5000);
					InputStream in = connection.getInputStream();
					//对服务器返回的输入流进行读取
					BufferedReader reader = new BufferedReader(new InputStreamReader(in));
					StringBuilder builder = new StringBuilder();
					String line;
					while((line = reader.readLine())!=null){
						builder.append(line);
					}
					
					//使用Message
					Message message = new Message();
					message.what = SHOW_RESPONSE_CONTENT;
					message.obj = builder.toString();
					handler.sendMessage(message);
				} catch (MalformedURLException e) {
					e.printStackTrace();
				} catch (IOException e) {
					e.printStackTrace();
				}finally{
					if(connection!=null){
						//断开连接
						connection.disconnect();
					}
				}
				
			}
		}).start();
	}
	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		// Inflate the menu; this adds items to the action bar if it is present.
		getMenuInflater().inflate(R.menu.main, menu);
		return true;
	}

}

3、获取网络访问权限

修改AndroidManifest.xml，添加：

<uses-permission android:name="android.permission.INTERNET"/>

4、结果

点击发送按钮，如下所示：




这就是服务器返回给我吗的Html代码。

如果是发送数据给服务器呢？看如下代码：

connection.setRequestMethod("POST");
					DataOutputStream out = new DataOutputStream(connection.getOutputStream());
					out.writeBytes("username=yy&password=admin");

此外，可以使用HttpClient发送Http请求，

其他不变，在MainActivity.java类中添加方法sendRequestWithHttpClient，如下：

private void sendRequestWithHttpClient(){
		new Thread(new Runnable() {
			@Override
			public void run() {
			
				try {
					HttpClient httpClient= new DefaultHttpClient();
					HttpGet httpGet = new HttpGet("http://www.baidu.com");
					HttpResponse httpResponse = httpClient.execute(httpGet);
					if(httpResponse.getStatusLine().getStatusCode() == 200){
						//请求和相应成功
						HttpEntity entity = httpResponse.getEntity();
						//防止中文乱码
						String responseText = EntityUtils.toString(entity,"utf-8");
						Message message = new Message();
						message.what = SHOW_RESPONSE_CONTENT;
						message.obj = responseText.toString();
						handler.sendMessage(message);
					}
				} catch (ClientProtocolException e) {
					e.printStackTrace();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		}).start();
	}

修改onClick方法，如下：

//重写点击方法
	@Override
	public void onClick(View view) {
		if(view.getId() == R.id.send_request){
			//如果是点击发送按钮，则处理Http请求--使用HttpURLConnection
		//	sendRequestWithHttpURLConnection();
			//如果是点击发送按钮，则处理Http请求--使用HttpClient
			sendRequestWithHttpClient();
		}
	}

效果如下：