Java基于Socket文件传输示例

落日映苍穹つ 2022-04-15 07:26 222阅读 0赞

Java基于Socket文件传输示例
    
    最近需要进行网络传输大文件，于是对基于socket的文件传输作了一个初步的了解。在一位网友提供的程序基础上，俺进行了一些加工，采用了缓冲输入/输出流来包装输出流，再采用数据输入/输出输出流进行包装，加快传输的速度。废话少说，先来看服务器端的程序。
    
    1.服务器端
    
    package sterning;
    
    import java.io.BufferedInputStream;
    import java.io.DataInputStream;
    import java.io.DataOutputStream;
    import java.io.File;
    import java.io.FileInputStream;
    import java.net.ServerSocket;
    import java.net.Socket;
    
    public class ServerTest {
        int port = 8821;
    
        void start() {
            Socket s = null;
            try {
                ServerSocket ss = new ServerSocket(port);
                while (true) {
                    // 选择进行传输的文件
                    String filePath = "D:\\lib.rar";
                    File fi = new File(filePath);
    
                    System.out.println("文件长度:" + (int) fi.length());
    
                    // public Socket accept() throws
                    // IOException侦听并接受到此套接字的连接。此方法在进行连接之前一直阻塞。
    
                    s = ss.accept();
                    System.out.println("建立socket链接");
                    DataInputStream dis = new DataInputStream(new BufferedInputStream(s.getInputStream()));
                    dis.readByte();
    
                    DataInputStream fis = new DataInputStream(new BufferedInputStream(new FileInputStream(filePath)));
                    DataOutputStream ps = new DataOutputStream(s.getOutputStream());
                    //将文件名及长度传给客户端。这里要真正适用所有平台，例如中文名的处理，还需要加工，具体可以参见Think In Java 4th里有现成的代码。
                    ps.writeUTF(fi.getName());
                    ps.flush();
                    ps.writeLong((long) fi.length());
                    ps.flush();
    
                    int bufferSize = 8192;
                    byte[] buf = new byte[bufferSize];
    
                    while (true) {
                        int read = 0;
                        if (fis != null) {
                            read = fis.read(buf);
                        }
    
                        if (read == -1) {
                            break;
                        }
                        ps.write(buf, 0, read);
                    }
                    ps.flush();
                    // 注意关闭socket链接哦，不然客户端会等待server的数据过来，
                    // 直到socket超时，导致数据不完整。                
                    fis.close();
                    s.close();                
                    System.out.println("文件传输完成");
                }
    
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    
        public static void main(String arg[]) {
            new ServerTest().start();
        }
    }
    
    2.socket的Util辅助类
    
    package sterning;
    
    import java.net.*;
    import java.io.*;
    
    public class ClientSocket {
        private String ip;
    
        private int port;
    
        private Socket socket = null;
    
        DataOutputStream out = null;
    
        DataInputStream getMessageStream = null;
    
        public ClientSocket(String ip, int port) {
            this.ip = ip;
            this.port = port;
        }
    
        /** *//**
         * 创建socket连接
         * 
         * @throws Exception
         *             exception
         */
        public void CreateConnection() throws Exception {
            try {
                socket = new Socket(ip, port);
            } catch (Exception e) {
                e.printStackTrace();
                if (socket != null)
                    socket.close();
                throw e;
            } finally {
            }
        }
    
        public void sendMessage(String sendMessage) throws Exception {
            try {
                out = new DataOutputStream(socket.getOutputStream());
                if (sendMessage.equals("Windows")) {
                    out.writeByte(0x1);
                    out.flush();
                    return;
                }
                if (sendMessage.equals("Unix")) {
                    out.writeByte(0x2);
                    out.flush();
                    return;
                }
                if (sendMessage.equals("Linux")) {
                    out.writeByte(0x3);
                    out.flush();
                } else {
                    out.writeUTF(sendMessage);
                    out.flush();
                }
            } catch (Exception e) {
                e.printStackTrace();
                if (out != null)
                    out.close();
                throw e;
            } finally {
            }
        }
    
        public DataInputStream getMessageStream() throws Exception {
            try {
                getMessageStream = new DataInputStream(new BufferedInputStream(socket.getInputStream()));
                return getMessageStream;
            } catch (Exception e) {
                e.printStackTrace();
                if (getMessageStream != null)
                    getMessageStream.close();
                throw e;
            } finally {
            }
        }
    
        public void shutDownConnection() {
            try {
                if (out != null)
                    out.close();
                if (getMessageStream != null)
                    getMessageStream.close();
                if (socket != null)
                    socket.close();
            } catch (Exception e) {
    
            }
        }
    }
    
    3.客户端
    
    package sterning;
    
    import java.io.BufferedOutputStream;
    import java.io.DataInputStream;
    import java.io.DataOutputStream;
    import java.io.FileOutputStream;
    
    public class ClientTest {
        private ClientSocket cs = null;
    
        private String ip = "localhost";// 设置成服务器IP
    
        private int port = 8821;
    
        private String sendMessage = "Windwos";
    
        public ClientTest() {
            try {
                if (createConnection()) {
                    sendMessage();
                    getMessage();
                }
    
            } catch (Exception ex) {
                ex.printStackTrace();
            }
        }
    
        private boolean createConnection() {
            cs = new ClientSocket(ip, port);
            try {
                cs.CreateConnection();
                System.out.print("连接服务器成功!" + "\n");
                return true;
            } catch (Exception e) {
                System.out.print("连接服务器失败!" + "\n");
                return false;
            }
    
        }
    
        private void sendMessage() {
            if (cs == null)
                return;
            try {
                cs.sendMessage(sendMessage);
            } catch (Exception e) {
                System.out.print("发送消息失败!" + "\n");
            }
        }
    
        private void getMessage() {
            if (cs == null)
                return;
            DataInputStream inputStream = null;
            try {
                inputStream = cs.getMessageStream();
            } catch (Exception e) {
                System.out.print("接收消息缓存错误\n");
                return;
            }
    
            try {
                //本地保存路径，文件名会自动从服务器端继承而来。
                String savePath = "E:\\";
                int bufferSize = 8192;
                byte[] buf = new byte[bufferSize];
                int passedlen = 0;
                long len=0;
                
                savePath += inputStream.readUTF();
                DataOutputStream fileOut = new DataOutputStream(new BufferedOutputStream(new BufferedOutputStream(new FileOutputStream(savePath))));
                len = inputStream.readLong();
                
                System.out.println("文件的长度为:" + len + "\n");
                System.out.println("开始接收文件!" + "\n");
                        
                while (true) {
                    int read = 0;
                    if (inputStream != null) {
                        read = inputStream.read(buf);
                    }
                    passedlen += read;
                    if (read == -1) {
                        break;
                    }
                    //下面进度条本为图形界面的prograssBar做的，这里如果是打文件，可能会重复打印出一些相同的百分比
                    System.out.println("文件接收了" +  (passedlen * 100/ len) + "%\n");
                    fileOut.write(buf, 0, read);
                }
                System.out.println("接收完成，文件存为" + savePath + "\n");
    
                fileOut.close();
            } catch (Exception e) {
                System.out.println("接收消息错误" + "\n");
                return;
            }
        }
    
        public static void main(String arg[]) {
            new ClientTest();
        }
    }
    这就实现了从服务器端向客户端发送文件的过程,当然,反过来,也一样.稍有不同.代码中对跨平台的细节没有实现,有时间或兴趣的朋友可以提供一下.