Android 文件断点上传器[多用户并发访问] / 憋错料

通过TCP/IP（SOCKET）协议实现文件断点上传（实现多用户并发访问）。

HTTP不支持文件断点续传，所以无法使用HTTP协议。

场景：

1. 网络不稳定，导致上传失败，下次不是从头开始，而是从断点开始上传；

2. 上传大文件，无法http上传，因为web服务器考虑到安全因素，会限制文件大小，一般10+m。

此文件断点上传器使用自定义协议。

服务器为上传的文件在服务器端生成唯一的sourceid关联上传文件，当客户端上传文件时，首次的sourceid为空，服务端先判断sourceid是否为空，如果为空，生成sourceid和下载断点position=0返回给客户端，如果不为空，把之前记录的sourceid和上次记录的当前下载断点position返回给客户端，客户端指定从文件的position位置开始上传数据。当下一次传文件时，服务器由sourceid关联到文件，找到sourceid对应文件的当前下载断点position返回给客户端，客户端从指定位置position开始上传数据。

服务器端：

FileServer.java

package cn.itcast.net.server;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PushbackInputStream;
import java.io.RandomAccessFile;
import java.net.ServerSocket;
import java.net.Socket;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import java.util.Properties;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import cn.itcast.utils.StreamTool;

public class FileServer {

     private ExecutorService executorService;//线程池
     private int port;//监听端口
     private boolean quit = false;//退出
     private ServerSocket server;
     private Map<Long, FileLog> datas = new HashMap<Long, FileLog>();//存放断点数据

     public FileServer(int port){
         this.port = port;
         //创建线程池，池中具有(cpu个数*50)条线程
         executorService = Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors() * 50);
     }
     /**
      * 退出
      */
     public void quit(){
        this.quit = true;
        try {
            server.close();
        } catch (IOException e) {
        }
     }
     /**
      * 启动服务
      * @throws Exception
      */
     public void start() throws Exception{
         server = new ServerSocket(port);
         while(!quit){
             try {
               Socket socket = server.accept();
               //为支持多用户并发访问，采用线程池管理每一个用户的连接请求
               executorService.execute(new SocketTask(socket));
             } catch (Exception e) {
               //  e.printStackTrace();
             }
         }
     }

     private final class SocketTask implements Runnable{
        private Socket socket = null;
        public SocketTask(Socket socket) {
            this.socket = socket;
        }

        public void run() {
            try {
                System.out.println("accepted connection "+ socket.getInetAddress()+ ":"+ socket.getPort());

                //创建回退流对象，将拆解的字节数组流传入
                //PushbackInputStream类继承了FilterInputStream类是iputStream类的修饰者。
                //提供可以将数据插入到输入流前端的能力。能够插入的最大字节数与推回缓冲区的大小相关。
                PushbackInputStream inStream = new PushbackInputStream(socket.getInputStream());

                //得到客户端发来的第一行协议数据：Content-Length=143253434;filename=xxx.3gp;sourceid=
                //如果用户初次上传文件，sourceid的值为空。
                String head = StreamTool.readLine(inStream);
                System.out.println(head);

                //黑客假如注入很长的第一行数据，那么服务器肯定会由于内存溢出而崩溃
                //实际项目中这里要判断第一行协议内容不能超过多长，设置一个长度上线，防止内存溢出异常。
                if(head!=null){
                    //下面从协议数据中提取各项参数值
                    String[] items = head.split(";");
                    String filelength = items[0].substring(items[0].indexOf("=")+1);
                    String filename = items[1].substring(items[1].indexOf("=")+1);
                    String sourceid = items[2].substring(items[2].indexOf("=")+1);
                    long id = System.currentTimeMillis();//生产资源id，如果需要唯一性，可以采用UUID
                    FileLog log = null;
                    if(sourceid!=null && !"".equals(sourceid)){
                        id = Long.valueOf(sourceid);
                        log = find(id);//查找上传的文件是否存在上传记录
                    }
                    File file = null;
                    int position = 0;
                    if(log==null){//如果不存在上传记录,为文件添加跟踪记录
                        String path = new SimpleDateFormat("yyyy/MM/dd/HH/mm").format(new Date());
                        File dir = new File("file/"+ path);
                        if(!dir.exists()) dir.mkdirs();
                        file = new File(dir, filename);
                        if(file.exists()){//如果上传的文件发生重名，然后进行改名
                            filename = filename.substring(0, filename.indexOf(".")-1)+ dir.listFiles().length+ filename.substring(filename.indexOf("."));
                            file = new File(dir, filename);
                        }
                        save(id, file);
                    }else{// 如果存在上传记录,读取已经上传的数据长度
                        file = new File(log.getPath());//从上传记录中得到文件的路径
                        if(file.exists()){
                            File logFile = new File(file.getParentFile(), file.getName()+".log");
                            if(logFile.exists()){
                                Properties properties = new Properties();
                                properties.load(new FileInputStream(logFile));
                                position = Integer.valueOf(properties.getProperty("length"));//读取已经上传的数据长度
                            }
                        }
                    }

                    OutputStream outStream = socket.getOutputStream();
                    String response = "sourceid="+ id+ ";position="+ position+ "\r\n";
                    //服务器收到客户端的请求信息后，给客户端返回响应信息：sourceid=1274773833264;position=0
                    //sourceid由服务器端生成，唯一标识上传的文件，position指示客户端从文件的什么位置开始上传
                    outStream.write(response.getBytes());

                    RandomAccessFile fileOutStream = new RandomAccessFile(file, "rwd");
                    if(position==0) fileOutStream.setLength(Integer.valueOf(filelength));//设置文件长度
                    fileOutStream.seek(position);//指定从文件的特定位置开始写入数据
                    byte[] buffer = new byte[1024];
                    int len = -1;
                    int length = position;
                    while( (len=inStream.read(buffer)) != -1){//从输入流中读取数据写入到文件中
                        fileOutStream.write(buffer, 0, len);
                        length += len;
                        Properties properties = new Properties();
                        properties.put("length", String.valueOf(length));
                        FileOutputStream logFile = new FileOutputStream(new File(file.getParentFile(), file.getName()+".log"));
                        properties.store(logFile, null);//实时记录已经接收的文件长度
                        logFile.close();
                    }
                    if(length==fileOutStream.length()) delete(id);
                    fileOutStream.close();
                    inStream.close();
                    outStream.close();
                    file = null;

                }
            } catch (Exception e) {
                e.printStackTrace();
            }finally{
                try {
                    if(socket!=null && !socket.isClosed()) socket.close();
                } catch (IOException e) {}
            }
        }
     }

     public FileLog find(Long sourceid){
         return datas.get(sourceid);
     }
     //保存上传记录
     public void save(Long id, File saveFile){
         //日后可以改成通过数据库存放
         datas.put(id, new FileLog(id, saveFile.getAbsolutePath()));
     }
     //当文件上传完毕，删除记录
     public void delete(long sourceid){
         if(datas.containsKey(sourceid)) datas.remove(sourceid);
     }

     private class FileLog{
        private Long id;
        private String path;
        public Long getId() {
            return id;
        }
        public void setId(Long id) {
            this.id = id;
        }
        public String getPath() {
            return path;
        }
        public void setPath(String path) {
            this.path = path;
        }
        public FileLog(Long id, String path) {
            this.id = id;
            this.path = path;
        }
     }

}

ServerWindow.java

package cn.itcast.net.server;

import java.awt.BorderLayout;
import java.awt.Frame;
import java.awt.Label;
import java.awt.event.WindowEvent;
import java.awt.event.WindowListener;

public class ServerWindow extends Frame{//服务端程序入口
    private FileServer s = new FileServer(7878);
    private Label label;

    public ServerWindow(String title){
        super(title);
        label = new Label();
        add(label, BorderLayout.PAGE_START);
        label.setText("服务器已经启动");
        this.addWindowListener(new WindowListener() {
            public void windowOpened(WindowEvent e) {
                new Thread(new Runnable() {
                    public void run() {
                        try {
                            s.start();
                        } catch (Exception e) {
                            //e.printStackTrace();
                        }
                    }
                }).start();
            }

            public void windowIconified(WindowEvent e) {
            }

            public void windowDeiconified(WindowEvent e) {
            }

            public void windowDeactivated(WindowEvent e) {
            }

            public void windowClosing(WindowEvent e) {
                 s.quit();
                 System.exit(0);
            }

            public void windowClosed(WindowEvent e) {
            }

            public void windowActivated(WindowEvent e) {
            }
        });
    }
    /**
     * @param args
     */
    public static void main(String[] args) {
        ServerWindow window = new ServerWindow("文件上传服务端");
        window.setSize(300, 300);
        window.setVisible(true);

    }

}

工具类StreamTool.java作用获取第一行自定义协议内容

package cn.itcast.utils;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PushbackInputStream;

public class StreamTool {

     public static void save(File file, byte[] data) throws Exception {
         FileOutputStream outStream = new FileOutputStream(file);
         outStream.write(data);
         outStream.close();
     }

     public static String readLine(PushbackInputStream in) throws IOException {
            char buf[] = new char[128];
            int room = buf.length;
            int offset = 0;
            int c;
loop:       while (true) {
                switch (c = in.read()) {
                    case -1:
                    case ‘\n‘:
                        break loop;
                    case ‘\r‘:
                        int c2 = in.read();
                        if ((c2 != ‘\n‘) && (c2 != -1)) in.unread(c2);
                        break loop;
                    default:
                        if (--room < 0) {
                            char[] lineBuffer = buf;
                            buf = new char[offset + 128];
                            room = buf.length - offset - 1;
                            System.arraycopy(lineBuffer, 0, buf, 0, offset);

                        }
                        buf[offset++] = (char) c;
                        break;
                }
            }
            if ((c == -1) && (offset == 0)) return null;
            return String.copyValueOf(buf, 0, offset);
    }

    /**
    * 读取流
    * @param inStream
    * @return 字节数组
    * @throws Exception
    */
    public static byte[] readStream(InputStream inStream) throws Exception{
            ByteArrayOutputStream outSteam = new ByteArrayOutputStream();
            byte[] buffer = new byte[1024];
            int len = -1;
            while( (len=inStream.read(buffer)) != -1){
                outSteam.write(buffer, 0, len);
            }
            outSteam.close();
            inStream.close();
            return outSteam.toByteArray();
    }
}

将服务器端转成可执行文件jar

运行启动服务器

Android客户端：

布局文件main.xml

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

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/filename" />

    <EditText
        android:id="@+id/filename"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="TeamTalk-Android.apk" />

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/button" />

    <ProgressBar
        android:id="@+id/uploadbar"
        style="?android:attr/progressBarStyleHorizontal"
        android:layout_width="fill_parent"
        android:layout_height="20px" />

    <TextView
        android:id="@+id/result"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:gravity="center" />

</LinearLayout>

本地信息存储用sqlite数据库。

MainActivity.java

package cn.itcast.upload;

import java.io.File;
import java.io.OutputStream;
import java.io.PushbackInputStream;
import java.io.RandomAccessFile;
import java.net.Socket;

import cn.itcast.service.UploadLogService;
import cn.itcast.utils.StreamTool;

import android.app.Activity;
import android.os.Bundle;
import android.os.Environment;
import android.os.Handler;
import android.os.Message;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity {
    private EditText filenameText;
    private TextView resultView;
    private ProgressBar uploadbar;
    private UploadLogService service;
    private Handler handler = new Handler(){
        @Override
        public void handleMessage(Message msg) {
            uploadbar.setProgress(msg.getData().getInt("length"));
            float num = (float)uploadbar.getProgress() / (float)uploadbar.getMax();
            int result = (int)(num * 100);
            resultView.setText(result + "%");
            if(uploadbar.getProgress() == uploadbar.getMax()){
                Toast.makeText(MainActivity.this, R.string.success, 1).show();
            }
        }
    };

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        service =  new UploadLogService(this);
        filenameText = (EditText)findViewById(R.id.filename);
        resultView = (TextView)findViewById(R.id.result);
        uploadbar = (ProgressBar)findViewById(R.id.uploadbar);
        Button button = (Button)findViewById(R.id.button);
        button.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                String filename = filenameText.getText().toString();
                if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){
                    File file = new File(Environment.getExternalStorageDirectory(), filename);
                    if(file.exists()){
                        uploadbar.setMax((int)file.length());
                        uploadFile(file);
                    }else{
                        Toast.makeText(MainActivity.this, R.string.notexsit, 1).show();
                    }
                }else{
                    Toast.makeText(MainActivity.this, R.string.sdcarderror, 1).show();
                }
            }
        });
    }

    private void uploadFile(final File file) {
        new Thread(new Runnable() {
            public void run() {
                try {
                    String sourceid = service.getBindId(file);
                    Socket socket = new Socket("192.168.0.83", 7878);
                    OutputStream outStream = socket.getOutputStream();
                    String head = "Content-Length="+ file.length() + ";filename="+ file.getName()
                        + ";sourceid="+(sourceid!=null ? sourceid : "")+"\r\n";
                    outStream.write(head.getBytes());

                    PushbackInputStream inStream = new PushbackInputStream(socket.getInputStream());
                    String response = StreamTool.readLine(inStream);
                    String[] items = response.split(";");
                    String responseSourceid = items[0].substring(items[0].indexOf("=")+1);
                    String position = items[1].substring(items[1].indexOf("=")+1);
                    if(sourceid==null){//如果是第一次上传文件，在数据库中不存在该文件所绑定的资源id
                        service.save(responseSourceid, file);
                    }
                    RandomAccessFile fileOutStream = new RandomAccessFile(file, "r");
                    fileOutStream.seek(Integer.valueOf(position));
                    byte[] buffer = new byte[1024];
                    int len = -1;
                    int length = Integer.valueOf(position);
                    while( (len = fileOutStream.read(buffer)) != -1){
                        outStream.write(buffer, 0, len);
                        length += len;//累加已经上传的数据长度
                        Message msg = new Message();
                        msg.getData().putInt("length", length);
                        handler.sendMessage(msg);
                    }
                    if(length == file.length()) service.delete(file);
                    fileOutStream.close();
                    outStream.close();
                    inStream.close();
                    socket.close();
                } catch (Exception e) {
                    Toast.makeText(MainActivity.this, R.string.error, 1).show();
                }
            }
        }).start();
    }
}

编译运行部署到模拟器上如下