Android - 向服务器发送数据(POST) - HTTPClient.

　　该篇文章主要说明使用Apache提供的HTTPClient,通过post方式,向服务器发送数据.由于有些东西在 Android - 向服务器发送数据(GET) 中提到过,就不再重复.

一,Android客户端的业务逻辑层:

package spt.http.post;

import java.io.IOException;
import java.net.MalformedURLException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

import org.apache.http.HttpResponse;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;

import android.os.Handler;
import android.util.Log;

/**
 * 用户向服务器端发送数据的类(使用post)方法.
 * 
 * @author Administrator
 * 
 */
public class PostSender {
	// 连接服务器的url.
	private static final String URL = "http://192.168.1.101:8080/ReceiveAndroid/ServletForPostMethod";
	// 标识是否连接到服务器成功.
	public static final int SEND_SUCCESS = 1;
	public static final int SEND_FAIL = 0;

	private Handler handler = null;	//新线程关联的Handler,用于将是否发送成功的标识Message放到消息队列中.

	public PostSender(Handler handler) {
		this.handler = handler;
	}

	/**
	 * 往服务器发送数据.
	 * 
	 * @param name
	 * @param pwd
	 */
	public void send(String name, String pwd) {
		// 这里params要传递到另外一个方法,加final为了防止被修改.
		final Map<String, String> params = new HashMap<String, String>();
		params.put("name", name);
		params.put("pwd", pwd);

		// 启动新的线程连接服务器.
		new Thread(new Runnable() {

			@Override
			public void run() {
				// 请求连接.
				try {
					if (postSend(params, URL, "utf-8"))
						handler.sendEmptyMessage(SEND_SUCCESS);
					else
						handler.sendEmptyMessage(SEND_FAIL);
				} catch (MalformedURLException e) {
					Log.d("sysout", "run:MalformedURLException" + e.getMessage());
				} catch (IOException e) {
					Log.d("sysout", "run:IOException" + e.getMessage());
				}
			}
		}).start();
	}

	/**
	 * 发送post请求的方法.
	 * 
	 * @param params
	 *            请求参数的键-值对.
	 * @param url
	 * @param encoding
	 *            使用指定编码对参数值进行编码.
	 * @return
	 * @throws MalformedURLException
	 * @throws IOException
	 */
	private boolean postSend(Map<String, String> params, String url,
			String encoding) throws MalformedURLException, IOException {
		// 封装请求参数的键值对.
		List<BasicNameValuePair> pairs = new ArrayList<BasicNameValuePair>();
		for (Entry<String, String> param : params.entrySet()) {
			pairs.add(new BasicNameValuePair(param.getKey(), param.getValue()));
		}
		//封装请求参数的实体.
		UrlEncodedFormEntity entity = new UrlEncodedFormEntity(pairs, encoding);
		//使用post请求.
		HttpPost post = new HttpPost(url);
		post.setEntity(entity);
		//使用DefaultHttpClient指定请求,以获取响应信息.
		DefaultHttpClient client = new DefaultHttpClient();
		HttpResponse response = client.execute(post);
		return response.getStatusLine().getStatusCode() == 200; // 等于200表示发送成功.
	}
}

 二,服务器端的Servlet,重写doPost方法:

package spt.servlet;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet("/ServletForPostMethod")
public class ServletForPostMethod extends HttpServlet{
	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;

	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		System.out.println("enter...post");
		String name = req.getParameter("name");
		String pwd = req.getParameter("pwd");
		System.out.println("name=" + name);
		System.out.println("pwd=" + pwd);
	}
	
	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//		System.out.println("enter...get");
//		String name = req.getParameter("name");
//		String pwd = req.getParameter("pwd");
//		System.out.println("name=" + name);
//		System.out.println("pwd=" + pwd);
	}
}

 另外,途中,我连几个小时的Tomcat服务器,后来通过log过滤,发现自己的问题,所以建议多使用log捕获异常信息.我在网上看到有位网友,使用HTTP进行post连接的时候,对url的处理和get一样,都是将参数拼接在原有url的后面,我觉得很奇怪.