Android应用开发之使用Socket进行大文件断点上传续传

http://www.linuxidc.com/Linux/2012-03/55567.htm

http://blog.csdn.net/shimiso/article/details/8529633/

在Android中上传文件可以采用HTTP方式，也可以采用Socket方式，但是HTTP方式不能上传大文件，这里介绍一种通过Socket方式来进行断点续传的方式，服务端会记录下文件的上传进度，当某一次上传过程意外终止后，下一次可以继续上传，这里用到的其实还是J2SE里的知识。

这个上传程序的原理是：客户端第一次上传时向服务端发送“Content-Length=35;filename=WinRAR_3.90_SC.exe;sourceid=“这种格式的字符串，服务端收到后会查找该文件是否有上传记录，如果有就返回已经上传的位置，否则返回新生成的sourceid以及position为0，类似”sourceid=2324838389;position=0“这样的字符串，客户端收到返回后的字符串后再从指定的位置开始上传文件。

首先是服务端代码：

SocketServer.java

package com.android.socket.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 com.android.socket.utils.StreamTool;

public class SocketServer {
    private ExecutorService executorService;// 线程池
    private ServerSocket ss = null;
    private int port;// 监听端口
    private boolean quit;// 是否退出
    private Map<Long, FileLog> datas = new HashMap<Long, FileLog>();// 存放断点数据，最好改为数据库存放

    public SocketServer(int port) {
        this.port = port;
        // 初始化线程池
        executorService = Executors.newFixedThreadPool(Runtime.getRuntime()
                .availableProcessors() * 50);
    }

    // 启动服务
    public void start() throws Exception {
        ss = new ServerSocket(port);
        while (!quit) {
            Socket socket = ss.accept();// www.linuxidc.com接受客户端的请求
            // 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));// 启动一个线程来处理请求
        }
    }

    // 退出
    public void quit() {
        this.quit = true;
        try {
            ss.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) throws Exception {
        SocketServer server = new SocketServer(8787);
        server.start();
    }

    private class SocketTask implements Runnable {
        private Socket socket;

        public SocketTask(Socket socket) {
            this.socket = socket;
        }

        @Override
        public void run() {
            try {
                System.out.println("accepted connenction from "
                        + socket.getInetAddress() + " @ " + socket.getPort());
                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);
                if (head != null) {
                    // 下面从协议数据中读取各种参数值
                    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();
                    FileLog log = null;
                    if (null != sourceid && !"".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){//如果上传的文件不存在上传记录,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{// 如果上传的文件存在上传记录,读取上次的断点位置
                        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"));//读取断点位置
                            }
                        }
                    }

                    OutputStream outStream = socket.getOutputStream();
                    String response = "sourceid="+ id+ ";position="+ position+ "
";
                    //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);//移动文件指定的位置开始写入数据
                    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);//实时记录文件的最后保存位置
                        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 FileLog(Long id, String path) {
            super();
            this.id = id;
            this.path = 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;
        }

    }
}

ServerWindow.java

package com.android.socket.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{
    private SocketServer server;
    private Label label;

    public ServerWindow(String title){
        super(title);
        server = new SocketServer(8787);
        label = new Label();
        add(label, BorderLayout.PAGE_START);
        label.setText("服务器已经启动www.linuxidc.com");
        this.addWindowListener(new WindowListener() {
            @Override
            public void windowOpened(WindowEvent e) {
                new Thread(new Runnable() {
                    @Override
                    public void run() {
                        try {
                            server.start();
                        } catch (Exception e) {
                            e.printStackTrace();
                        }
                    }
                }).start();
            }

            @Override
            public void windowIconified(WindowEvent e) {
            }

            @Override
            public void windowDeiconified(WindowEvent e) {
            }

            @Override
            public void windowDeactivated(WindowEvent e) {
            }

            @Override
            public void windowClosing(WindowEvent e) {
                 server.quit();
                 System.exit(0);
            }

            @Override
            public void windowClosed(WindowEvent e) {
            }

            @Override
            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

package com.android.socket.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 '
':
                        break loop;
                    case '
':
                        int c2 = in.read();
                        if ((c2 != '
') && (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();
    }
}

Android客户端代码：