java基于Socket做一个简单下载器

本文实例为大家分享了java基于Socket制作下载器的过程，及相关代码，供大家参考，具体内容如下

1.首先要建立一个服务器用来处理信息并给客户端传输文件(电脑)
 我是用电脑开了一个WIFI，手机连上后使用scoket传输的 
SERVERIP要根据自己实际情况更改。端口也可以随便更改0~65535，尽量选大一点

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;

/**
 * 测试Android客户端与PC服务器通过socket进行交互 服务器端：接收客户端的信息并回送给客户
 *
 * @author Ameyume
 *
 */
public class Server implements Runnable {
 //定义传输的IP和端口信息
 public static final String SERVERIP = "192.168.155.1";
 //定义的9888端口
 public static final int SERVERPORT = 9888;
 //定义文件
 private File file = null;

 public static void main(String[] args) {
 //建立调用线程执行传输的方法
 Thread desktopServerThread = new Thread(new Server());
 desktopServerThread.start();
 }

 public void run() {
 try {
  System.out.println("S: Connecting...9888");

  //创建套接字
  ServerSocket serverSocket = new ServerSocket(SERVERPORT);
  while (true) {
  // 等待接受客户端请求
  Socket client = serverSocket.accept();

  System.out.println("S: Receiving...9888");

  try {

   // 接受客户端信息
   BufferedReader in = new BufferedReader(
    new InputStreamReader(client.getInputStream()));
   System.out.println("S: 接收客户端信息");
   // 读取客户端的信息
   String str = in.readLine();
   String str1 = str.substring(0,2);
   String str2 = str.substring(2);
   System.out.println(str);
   //根据客户端的请求找到对应的文件并把文件大小的值传过去
   if (str.equals("file_size")) {

   //定义你要传输的文件（我这里写的是E盘下的某个文件）
   file = new File("E:\\某个文件");
   //输入流
   FileInputStream fis = new FileInputStream(file);
   //输出流
   BufferedInputStream bis = new BufferedInputStream(fis);
   //计算将要传输的文件大小
   int sum = bis.available();
   //将int型的文件大小转成字符串
   String s = String.valueOf(sum);
   System.out.println(s);
   //建立输出流以发送文件大小的信息
   PrintWriter out = new PrintWriter(new BufferedWriter(
    new OutputStreamWriter(client.getOutputStream())),
    true);
   //发送文件的大小信息
   out.println(s);
   //关闭流
   out.flush();
   bis.close();

   } else if (str1.equals("ok")) {
   int a = Integer.parseInt(str2);

   // 客户端收到文件大小的值后，再根据客户端传来的“ok”将文件传过去
   BufferedOutputStream bos = new BufferedOutputStream(
    client.getOutputStream());

   System.out.println("S: 开始传输");

   //开始传输
   if (true) {
    //输入流
    FileInputStream fis = new FileInputStream(file);
    //跳过前面已经传输过的字节
    fis.skip(a);
    //缓冲输入流
    BufferedInputStream bis = new BufferedInputStream(
     fis);

    int t = -1;
    while ((t = bis.read()) >= 0) {
    bos.write(t);
    }

    String s = "已传输";
    //关闭流
    bos.flush();
    bis.close();
    bos.close();
    // serverSocket.close();

    System.out.println("S: Received: '" + s + "'");
   }
   } else {
   System.out
    .println("Not receiver anything from client!");
   }
  } catch (Exception e) {
   System.out.println("S: Error 1");
   e.printStackTrace();
  } finally {
   client.close();
   System.out.println("S: Done.");
  }
  }
 } catch (Exception e) {
  System.out.println("S: Error 2");
  e.printStackTrace();
 }
 }

}

2.再建立一个客户端，我这里用的是安卓写的MainActivity.java（我是在手机上运行的）

package com.xhy.zz;

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

public class MainActivity extends Activity {

 // 定义Handler
 public static Handler myHandler;

 // 定义intent
 private Intent intent;

 // 获取控件
 private TextView text_name;
 private TextView text_percent;
 private Button btn_start;
 private Button btn_stop;

 // 文件显示
 private TextView text_sel_file;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
 // TODO Auto-generated method stub
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);

 text_name = (TextView) findViewById(R.id.text_name);

 text_percent = (TextView) findViewById(R.id.text_percent);

 btn_start = (Button) findViewById(R.id.btn_start);

 btn_stop = (Button) findViewById(R.id.btn_stop);

 // 按钮一的返回信息，显示进度
 myHandler = new Handler() {
  @Override
  public void handleMessage(Message msg) {
  super.handleMessage(msg);

  if (msg.what == 0x0001) {
   Bundle data = msg.getData();
   String str = data.getString("value");
   text_percent.setText(str);
  }
  }
 };
 // 显式的方式调用HelloService
 intent = new Intent(this, DownService.class);
 // 设置启动按钮点击事件
 btn_start.setOnClickListener(new OnClickListener() {
  @Override
  public void onClick(View v) {

  // 开启服务
  startService(intent);

  }
 });
 // 设置停止按钮点击事件
 btn_stop.setOnClickListener(new OnClickListener() {
  @Override
  public void onClick(View v) {
  // 关闭服务
  stopService(intent);
  }
 });

 }

 /***
 * 被调用Activity一旦返回值 该回调方法将被系统自动调用
 */
 @Override
 protected void onActivityResult(int requestCode, int resultCode,
  Intent intent) {
 super.onActivityResult(requestCode, resultCode, intent);
 // 如果请求码是0
 // 并且返回的结果码为1
 // 请求的Activity可能返回多种结果码
 if (requestCode == 0 && resultCode == 1) {
  // 取出数据
  Bundle data = intent.getExtras();
  String str = data.getString("files");
  // 显示数据
  text_sel_file.setText(str);
 }
 }

}

3.activity_main.xml文件

 <?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:orientation="vertical" >

  <LinearLayout
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginTop="20dp"
    android:orientation="horizontal" >

    <TextView
      android:id="@+id/text_name"
      android:layout_width="160dp"
      android:layout_height="wrap_content"
      android:layout_gravity="center_vertical"
      android:text="1" />

    <TextView
      android:id="@+id/text_percent"
      android:layout_width="50dp"
      android:layout_height="wrap_content"
      android:layout_gravity="center_vertical"
      android:layout_marginLeft="20dp"
      android:text="0%"/>

    <LinearLayout
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_marginLeft="20dp"
      android:orientation="vertical" >
      <Button
        android:id="@+id/btn_start"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="start"
        />
      <Button
        android:id="@+id/btn_stop"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="stop"
        />

    </LinearLayout>
  </LinearLayout>
</LinearLayout>

4.DownService用于在后台开启线程执行下载

package com.xhy.zz;

import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.net.InetAddress;
import java.net.Socket;
import java.net.UnknownHostException;

import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.os.Environment;
import android.os.IBinder;
import android.os.Message;
import android.util.Log;

public class DownService extends Service {
 private static final String TAG = "Socket_Android";

 // Preferece机制操作的文件名
 public static final String PREFERENCE_NAME = "DownService";
 // Preferece机制的操作模式
 public static int MODE = Context.MODE_PRIVATE;

 // 线程
 private Thread workThread;
 // 定义文件名
 private String filename="file";

 // 端口号
 private int port = 9888;

 private boolean isStop = false;

 /***
 * 必须要实现的方法
 */
 @Override
 public IBinder onBind(Intent intent) {
 return null;
 }

 @Override
 public void onCreate() {
 super.onCreate();

 }

 @Override
 public int onStartCommand(Intent intent, int flags, int startId) {

 Log.v("TCP", filename);
 // 建立传输的方法
 Runnable backgroundWork = new Runnable() {
  @Override
  public void run() {

   // setTitle("测试Socket连接");
   Socket socket = null;
   Socket socket1 = null;

   try {
   /*
    * 指定Server的IP地址，此地址为局域网地址，如果是使用WIFI上网，则为PC机的WIFI IP地址
    * 在ipconfig查看到的IP地址如下： Ethernet adapter 无线网络连接:
    * Connection-specific DNS Suffix . : IP Address. . . .
    * . . . . . . . . : 192.168.155.1
    */
   InetAddress serverAddr = InetAddress
    .getByName("192.168.155.1");// TCPServer.SERVERIP
   Log.d("TCP", "C: Connecting...");
   Log.d("TCP", filename + " " + port);
   // 应用Server的IP和端口建立Socket对象，向服务端发送请求获取文件大小的值
   socket1 = new Socket(serverAddr, port);
   String message = "---Test_Socket_Android---";

   Log.d("TCP", "C: Sending: '" + message + "'");

   // 将信息通过这个对象来发送给Server
   PrintWriter out = new PrintWriter(new BufferedWriter(
    new OutputStreamWriter(
     socket1.getOutputStream())), true);

   // 把用户输入的内容发送给server
   out.println("file_size");
   out.flush();

   // 接收服务器信息
   BufferedReader in = new BufferedReader(
    new InputStreamReader(socket1.getInputStream()));
   // 获取文件大小
   String str1 = in.readLine();

   Log.d("TCP", str1);
   // 将文件大小转成int型
   int sum = Integer.parseInt(str1);
   Log.d("TCP", str1);
   // 关闭输入流
   in.close();

   SharedPreferences sharedPreferences = getSharedPreferences(
    PREFERENCE_NAME, MODE);

   SharedPreferences.Editor editor = sharedPreferences
    .edit();
   //取出已经传输了的字节
   int pre = sharedPreferences.getInt("DownService", 0);
   int _pre = pre;
   //将其转化为字符串以便发送给服务端
   String s = String.valueOf(_pre);

   // 应用Server的IP和端口建立Socket对象再次向服务端发送请求，以获取文件内容
   socket = new Socket(serverAddr, port);

   // 向服务端发送请求获得文件的字符
   PrintWriter out1 = new PrintWriter(
    new BufferedWriter(new OutputStreamWriter(
     socket.getOutputStream())), true);

   out1.println("ok"+s);
   out1.flush();
   out.close();

   // 定义输入流
   BufferedInputStream bis = new BufferedInputStream(
    socket.getInputStream());

   String file1 = filename;
   String file;
   // 判断手机是否插入了SDCard，是则将文件插入内存卡
   if (Environment.getExternalStorageState().equals(
    Environment.MEDIA_MOUNTED)) {
    File sdCard = Environment
     .getExternalStorageDirectory();

    // SD卡定义文件
    file = sdCard.getCanonicalFile() + "/" + file1;
    // 定义文件输出流
    FileOutputStream fos = new FileOutputStream(file,true);
    try {
    int t = -1;
    int downloaded = pre;

    // 定义每次传输的字节数
    byte[] buff = new byte[8192];
    Log.i("sum", sum + "");
    // 开始将服务端的文件写入手机SD卡中
    while ((t = bis.read(buff)) != -1) {
     if (isStop == true) {
     break;
     }
     fos.write(buff, 0, t);
     downloaded += t;

     //将传输的进度存储起来
     editor.putInt("DownService", downloaded);
     editor.commit();

     //当传完了则把存储信息归零
     if (downloaded == sum) {
     editor.putInt("DownService", 0);
     editor.commit();
     }
     // 获得文件传输的进度
     float wb = ((downloaded * 100) / (float) sum);
     int wi = (int) wb;
     System.out.println(downloaded);
     String str = String.valueOf(wi) + "%";

     // 将文件的传输进度给送给BaseActivity,以显示给用户
     Message msg = new Message(); // 生成消息
     // 生成消息
     msg.what = 0x0001; // 设置消息类型
     // 生成Bundle携带数据
     Bundle data = new Bundle();
     data.putString("value", str);
     msg.setData(data);
     // 利用Handler发送消息
     MainActivity.myHandler.sendMessage(msg);

    }

    // 关闭输入输出流
    bis.close();
    fos.flush();
    fos.close();

    } catch (Exception e) {
    bis.close();
    fos.flush();
    fos.close();
    }
   }
   Log.d(TAG, "From server:'已接收" + "'");
   } catch (UnknownHostException e) {
   Log.e(TAG, "192.168.155.1 is unkown server!");
   } catch (Exception e) {
   e.printStackTrace();
   } finally {
   try {
    socket.close();
   } catch (Exception e) {
    e.printStackTrace();
   }
   }

  }

 };
 workThread = new Thread(backgroundWork);
 // isAlive方法用于判断workThread线程是否被开启
 if (!workThread.isAlive()) {
  // 生成新线程
  workThread.start();
  Log.v("ServiceLife", "线程开始工作");
 } else {
  Log.v("workThread", "线程已经被调用");
 }

 return START_STICKY;
 }

 @Override
 public void onDestroy() {

 super.onDestroy();
 // 利用interrupt方式中断该线程
 isStop = true;

 Log.v("ServiceLife", "onDestroy方法被调用");
 }

}

5、最后别忘了注册AndroidManifest.xml

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

 <service android:name=".DownService" ></service>

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持我们。