Android 使用HTTP（get和post）方式登陆服务器

package com.wuyou.submittoserver;



import android.os.Bundle;

import android.support.v7.app.ActionBarActivity;

import android.text.TextUtils;

import android.view.View;

import android.widget.EditText;

import android.widget.Toast;



import java.io.BufferedReader;

import java.io.ByteArrayOutputStream;

import java.io.IOException;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.io.OutputStream;

import java.net.HttpURLConnection;

import java.net.URL;

import java.net.URLEncoder;



public class MainActivity extends ActionBarActivity {



    private static final int OK = 200;

    private EditText usernameEditText;

    private EditText passwrodEditText;



    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);



        usernameEditText = (EditText) findViewById(R.id.username);

        passwrodEditText = (EditText) findViewById(R.id.password);

    }



    /**

     * post方法多了三个东西：

     * ①请求的表单类型

     * ②请求的数据长度

     * ③请求的数据并且写给服务器

     */

    public void post(View view) {

        final String username = usernameEditText.getText().toString().trim();

        final String password = passwrodEditText.getText().toString().trim();

        //Android默认模拟器外部的地址为10.0.2.2，而不是localhost和127.0.0.1

        final String serverPath = "http://10.0.2.2:8080/LoginServlet";

        if (TextUtils.isEmpty(username) || TextUtils.isEmpty(password)) {

            //给出提示：账号密码不许为空

        } else {

            new Thread(new Runnable() {

                @Override

                public void run() {

                    try {

                        //向服务器请求的数据

                        String data = "username=" + URLEncoder.encode(username,"UTF-8") + "&password=" + URLEncoder.encode(password,"UTF-8");

                        URL url = new URL(serverPath);

                        HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();

                        httpURLConnection.setRequestMethod("POST");

                        httpURLConnection.setConnectTimeout(3000);

                        httpURLConnection.setDoOutput(true);//打开输出流，以便向服务器提交数据

                        //设置请求体的类型是文本类型

                        httpURLConnection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");

                        //设置请求体的长度

                        httpURLConnection.setRequestProperty("Content-Length", String.valueOf(data.length()));

                        //获得输出流，向服务器写入数据

                        OutputStream outputStream = httpURLConnection.getOutputStream();

                        outputStream.write(data.getBytes());



                        int responseCode = httpURLConnection.getResponseCode();

                        if (200 == responseCode) {

                            InputStream inputStream = httpURLConnection.getInputStream();

                            final String responseMsg = StreamTool.getString(inputStream);

                            runOnUiThread(new Runnable() {

                                @Override

                                public void run() {

                                    Toast.makeText(MainActivity.this, responseMsg, Toast.LENGTH_LONG).show();

                                }

                            });

                        } else {

                            System.out.println("responseCode = " + responseCode);

                            //连接服务器出错，错误代码为：responseCode 根据代码值告诉用户出错的原因

                            //....

                        }

                    } catch (Exception e) {

                        e.printStackTrace();

                    }

                }

            }).start();

        }

    }



    public void get(View view) {

        final String username = usernameEditText.getText().toString().trim();

        final String password = passwrodEditText.getText().toString().trim();

        //Android默认模拟器外部的地址为10.0.2.2，而不是localhost和127.0.0.1

        final String serverPath = "http://10.0.2.2:8080/LoginServlet";

        if (TextUtils.isEmpty(username) || TextUtils.isEmpty(password)) {

            //给出提示：账号密码不许为空

        } else {

            new Thread(new Runnable() {

                @Override

                public void run() {

                    try {

                        //使用GET方式请求服务器只能这样

                        URL url = new URL(serverPath + "?username=" + URLEncoder.encode(username,"UTF-8") + "&password=" + URLEncoder.encode(password,"UTF-8"));

                        HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();

                        httpURLConnection.setRequestMethod("GET");

                        httpURLConnection.setConnectTimeout(5000);

                        httpURLConnection.setRequestProperty("User-Agent", "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:22.0) Gecko/20100101 Firefox/22.0");

                        int responseCode = httpURLConnection.getResponseCode();

                        if (200 == responseCode) {

                            InputStream inputStream = httpURLConnection.getInputStream();

                            final String responseMsg = StreamTool.getString(inputStream);

                            runOnUiThread(new Runnable() {

                                @Override

                                public void run() {

                                    Toast.makeText(MainActivity.this, responseMsg, Toast.LENGTH_LONG).show();

                                }

                            });

                        } else {

                            System.out.println("responseCode = " + responseCode);

                            //连接服务器出错，错误代码为：responseCode 根据代码值告诉用户出错的原因

                            //....

                        }

                    } catch (Exception e) {

                        e.printStackTrace();

                    }

                }

            }).start();

        }

    }

}



class StreamTool {

    public static String getString(InputStream inputStream) throws IOException {

        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();

        byte[] buf = new byte[1024];

        int length;

        while((length = inputStream.read(buf)) >0) {

            byteArrayOutputStream.write(buf, 0 ,length);

        }

        byte[] stringBytes = byteArrayOutputStream.toByteArray();

        String str = new String(stringBytes);

        return str;

    }

}

界面就不写了。

要注意几个地方：

①模拟器访问本机服务器127.0.01（locahost）的话，使用的地址是：10.0.2.2

②post比get方法多了三个要发送的数据头(header)