使用HttpClient发送请求,接收响应很简单,只要5步:

  1. 创建HttpClient 对象

  2. 创建HttpGet对象;或者是HttpPost 对象

  3. 如果需要发送请求参数,可以调用HttpGet HttpPost共同的setParams(HttpParams params) 方法来添加请求参数;对于HttpPost对象,也可以调用setEntity(HttpEntity entity)方法来设置请求参数



客户端条件参数:
List params = new
                                                    ArrayList();
                                            params.add(new BasicNameValuePair
                                                    ("LoginName", name));
                                            params.add(new BasicNameValuePair
                                                    ("LoginPassword", pass));
                                            // 设置编码
                                            post.setEntity(new UrlEncodedFormEntity(
                                                    params, HTTP.UTF_8));
服务器端接收:
String loginName = request.getParameter("LoginName");
String loginPassword = request.getParameter("LoginPassword");

4.调用HttpClient对象的excute()发送请求,返回一个HttpResponse 对象。

5.调用HttpResponse的getAllHeaders(),getHeaders()等方法可以获取服务器的响应头;调用HttpResponse的getEntity()可以获取HttpEntity对象,该对象包转了服务器的响应内容。


登录的实例:核心代码

   服务器端用的servlet搭建

package LoginServlet;

import java.io.IOException;
import java.io.PrintWriter;

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

public class AndroidLoginServler extends HttpServlet {

	private static final long serialVersionUID = 1L;

	public AndroidLoginServler() {
		super();
	}

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		this.doPost(request, response);
		System.out.println("doGet");

	}

	// Url 地址
	// http://localhost:8080/Android_Client/servlet/AndroidLoginServler?LoginName=yu&LoginPassword=123
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		System.out.println("doPost");
		request.setCharacterEncoding("UTF-8");
		String loginName = request.getParameter("LoginName");
		String loginPassword = request.getParameter("LoginPassword");
		System.out.println(loginName);
		System.out.println(loginPassword);
		// 统一字符 避免乱码
		response.setCharacterEncoding("UTF-8");
		response.setContentType("text/html;charset=UTF-8");
		PrintWriter out = null;
		try {
			/*
			 * 登录业务判断
			 */
			out=response.getWriter();
			
			if (loginName.equals("yu") && loginPassword.equals("123")) {
				// 登陆成功
				out.print("success");
			} else {
				// 登陆失败
				out.print("failed");
			}
		} finally {
			if (out != null)
				out.close();
		}
	}

}

客户端

package com.example.xiaocool.httpclienttest;

import android.app.AlertDialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import android.support.v7.app.ActionBarActivity;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.protocol.HTTP;
import org.apache.http.util.EntityUtils;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;


public class MainActivity extends ActionBarActivity {

    TextView response;
    HttpClient httpClient;
    Handler handler = new Handler() {
        public void handleMessage(Message msg) {
            if (msg.what == 0x123) {

                response.append(msg.obj.toString() + "\n");
            }
        }
    };

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        // 创建DefaultHttpClient对象
        httpClient = new DefaultHttpClient();
        response = (TextView) findViewById(R.id.response);
    }

    public void accessSecret(View v) {
        response.setText("");
        new Thread() {
            @Override
            public void run() {
                // 创建HttpGet对象
                HttpGet get = new HttpGet(
                        "http://112.237.241.204:8080/Android_Client/servlet/AndroidLoginServler?LoginName=yu&LoginPassword=123");
                try {
                    // 发送get
                    HttpResponse httpResponse = httpClient.execute(get);
                    HttpEntity entity = httpResponse.getEntity();
                    if (entity != null) {

                        BufferedReader br = new BufferedReader(
                                new InputStreamReader(entity.getContent()));
                        String line = null;

                        while ((line = br.readLine()) != null) {
                            Message msg = new Message();
                            msg.what = 0x123;
                            msg.obj = line;
                            handler.sendMessage(msg);
                        }
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }.start();
    }

    public void showLogin(View v) {
        //加载登陆界面
        final View loginDialog = getLayoutInflater().inflate(
                R.layout.login, null);
        //使用对话框供用户登陆系统
       new AlertDialog.Builder(MainActivity.this)
                .setTitle("登录系统")
                .setView(loginDialog)
                .setPositiveButton("登陆",
                        new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialog,
                                                int which) {
                                final String name = ((EditText) loginDialog
                                        .findViewById(R.id.name)).getText()
                                        .toString();
                                final String pass = ((EditText) loginDialog
                                        .findViewById(R.id.pass)).getText()
                                        .toString();
                                /*final String uri="http://112.237.241.204:8080/Android_Client/servlet/AndroidLoginServler?LoginName=" +
                                        name+"&LoginPassword="+pass;*/
                                final String uri="http://112.237.241.204:8080/Android_Client/servlet/AndroidLoginServler";
                                new Thread() {
                                    @Override
                                    public void run() {
                                        try {
                                            HttpPost post = new HttpPost(uri);
                                            /**
                                             *
                                             定义了一个list,该list的数据类型是NameValuePair(简单名称值对节点类型,
                                             这个代码多处用于Java像url发送Post请求。在发送post请求时用该list来存放参数
                                             */
                                            List params = new
                                                    ArrayList();
                                            params.add(new BasicNameValuePair
                                                    ("LoginName", name));
                                            params.add(new BasicNameValuePair
                                                    ("LoginPassword", pass));
                                            // 设置编码
                                            post.setEntity(new UrlEncodedFormEntity(
                                                    params, HTTP.UTF_8));

                                            HttpResponse response = httpClient
                                                    .execute(post);
                                            // 如果服务器成功返回响应
                                            if (response.getStatusLine()
                                                    .getStatusCode() == 200) {
                                                String msg = EntityUtils
                                                        .toString(response.getEntity());
                                                Looper.prepare();
                                                //显示从服务器返回的信息
                                                Toast.makeText(MainActivity.this,
                                                        msg, Toast.LENGTH_SHORT).show();
                                                Looper.loop();
                                            }
                                        } catch (Exception e) {
                                            e.printStackTrace();
                                        }
                                    }
                                }.start();
                            }
                        }).setNegativeButton("取消", null).show();
    }
}

Android 网络应用--Apache HttpClient的使用_第1张图片

Android 网络应用--Apache HttpClient的使用_第2张图片

Android 网络应用--Apache HttpClient的使用_第3张图片