采用HttpURLConnection的POST方式实现登陆案例

        

MainActivity.java

package com.example.webserver;

import java.io.ByteArrayOutputStream;  
import java.io.InputStream;  
import java.io.OutputStream;  
import java.net.HttpURLConnection;  
import java.net.URL;  
import java.net.URLEncoder;  
  
import android.app.Activity;  
import android.os.Bundle;  
import android.text.TextUtils;  
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;  
import android.widget.TextView;  
import android.widget.Toast;  
  
public class MainActivity extends Activity implements OnClickListener{  
    // 声明控件对象  
    private EditText et_name, et_pass;  
    // 声明显示返回数据库的控件对象  
    private TextView tv_result;  
    private  Button login;
    @Override  
    protected void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        // 设置显示的视图  
        setContentView(R.layout.main);  
        // 通过 findViewById(id)方法获取用户名的控件对象  
        et_name = (EditText) findViewById(R.id.username);  
        // 通过 findViewById(id)方法获取用户密码的控件对象  
        et_pass = (EditText) findViewById(R.id.password);  
        login=(Button) findViewById(R.id.ok);
        // 通过 findViewById(id)方法获取显示返回数据的控件对象  
        tv_result = (TextView) findViewById(R.id.backdata);  
        login.setOnClickListener(this);
    }  
  
    /** 
     * 通过android:onClick="login"指定的方法 ， 要求这个方法中接受你点击控件对象的参数v 
     *  
     * @param v 
     */  
/*    public void login(View v) {  
       
        
    }  
  */
    /** 
     * POST请求操作 
     *  
     * @param userName 
     * @param userPass 
     */  
    public void loginByPost(String userName, String userPass) {    
        try {  
            // 请求的地址  
            String spec = "http://10.28.197.117:8080/test/LoginServlet";  
            // 根据地址创建URL对象  
            URL url = new URL(spec);  
            // 根据URL对象打开链接  
            HttpURLConnection urlConnection = (HttpURLConnection) url  
                    .openConnection();  
            // 设置请求的方式  
            urlConnection.setRequestMethod("POST");  
            // 设置请求的超时时间  
            urlConnection.setReadTimeout(5000);  
            urlConnection.setConnectTimeout(5000);  
            // 传递的数据  
            String data = "username=" + URLEncoder.encode(userName, "UTF-8")  
                    + "&userpass=" + URLEncoder.encode(userPass, "UTF-8");  
            // 设置请求的头  
            urlConnection.setRequestProperty("Connection", "keep-alive");  
            // 设置请求的头  
            urlConnection.setRequestProperty("Content-Type",  
                    "application/x-www-form-urlencoded");  
            // 设置请求的头  
            urlConnection.setRequestProperty("Content-Length",  
                    String.valueOf(data.getBytes().length));  
            // 设置请求的头  
            urlConnection  
                    .setRequestProperty("User-Agent",  
                            "mozilla/5.0 (windows nt 6.1; win64; x64) applewebkit/537.36 (khtml, like gecko) chrome/55.0.2883.87 safari/537.36");  
  
            urlConnection.setDoOutput(true); // 发送POST请求必须设置允许输出  
            urlConnection.setDoInput(true); // 发送POST请求必须设置允许输入  
                                            //setDoInput的默认值就是true  
            //获取输出流  
            OutputStream os = urlConnection.getOutputStream();  
            os.write(data.getBytes());  
            os.flush();  
            if (urlConnection.getResponseCode() == 200) {  
                // 获取响应的输入流对象  
                InputStream is = urlConnection.getInputStream();  
                // 创建字节输出流对象  
                ByteArrayOutputStream baos = new ByteArrayOutputStream();  
                // 定义读取的长度  
                int len = 0;  
                // 定义缓冲区  
                byte buffer[] = new byte[1024];  
                // 按照缓冲区的大小，循环读取  
                while ((len = is.read(buffer)) != -1) {  
                    // 根据读取的长度写入到os对象中  
                    baos.write(buffer, 0, len);  
                }  
                // 释放资源  
                is.close();  
                baos.close();  
                // 返回字符串  
                final String result = new String(baos.toByteArray());  
  
                // 通过runOnUiThread方法进行修改主线程的控件内容  
                MainActivity.this.runOnUiThread(new Runnable() {  
                    @Override  
                    public void run() {  
                        // 在这里把返回的数据写在控件上 会出现什么情况尼  
                        tv_result.setText(result);  
                    }  
                });  
  
            } else {  
                System.out.println("链接失败.........");  
            }  
        } catch (Exception e) {  
            e.printStackTrace();  
        }  
    }

    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub
        // 获取点击控件的id  
        int id = v.getId();  
        // 根据id进行判断进行怎么样的处理  
        switch (id) {  
        // 登陆事件的处理  
        case R.id.ok:  
            // 获取用户名  
            final String userName = et_name.getText().toString();  
            // 获取用户密码  
            final String userPass = et_pass.getText().toString();  
            if (TextUtils.isEmpty(userName) || TextUtils.isEmpty(userPass)) {  
                Toast.makeText(this, "用户名或者密码不能为空", Toast.LENGTH_LONG).show();  
            } else {  
                // 开启子线程  
                System.out.println("发送到服务器");  
                new Thread() {  
                    public void run() {  
                        loginByPost(userName, userPass); // 调用loginByPost方法  
                    };  
                }.start();  
            }  
            break;  
        }  
  
    }  
  
}  

 LoginServlet.java

package test;
import java.io.IOException;  
import javax.servlet.ServletException;  
import javax.servlet.http.HttpServlet;  
import javax.servlet.http.HttpServletRequest;  
import javax.servlet.http.HttpServletResponse;  
  
public class LoginServlet extends HttpServlet {  
  
    /** 
     *  cvcjh11
     */  
    private static final long serialVersionUID = 1L;  
  
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {  
        //获取请求的参数值  
        String userName = request.getParameter("username");  
        String userPass = request.getParameter("userpass");  
          
        System.out.println("在没有转码之前的"+userName+"---"+userPass);  
        //GET方式的请求乱码处理  
        userName = new String(userName.getBytes("ISO8859-1"),"UTF-8");  
        userPass = new String(userPass.getBytes("ISO8859-1"),"UTF-8");  
  
        System.out.println("在转码之后---"+userName+"---"+userPass);  
        if("111".equals(userName)&&"111".equals(userPass)){  
            //响应登陆成功的信息  
            response.getOutputStream().write("ok".getBytes());   
        }else{  
            //相应登陆失败的信息  
            response.getOutputStream().write("fail".getBytes());  
        }  
          
    }  
  
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {  
        this.doGet(request, response);  
    }  
  
}  

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>test</display-name>
  <servlet>  
    <description></description>  
    <display-name>LoginServlet</display-name>  
    <servlet-name>LoginServlet</servlet-name>  
    <servlet-class>test.LoginServlet</servlet-class>  
  </servlet>  
    
  <servlet-mapping>  
    <servlet-name>LoginServlet</servlet-name>  
    <url-pattern>/LoginServlet</url-pattern>  
  </servlet-mapping>  
</web-app>

Androidmanifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.webserver"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="18"
        android:targetSdkVersion="23" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>           
    </application>
    <uses-permission android:name="android.permission.INTERNET"/>    
</manifest>

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