Socket realizes file transfer
1. client
Connect to the server through new Socket("ip",port)
Create file input stream read file
Create an output stream that returns to the socket
Write article name, length and other attributes
Read and write articles
Closed flow
package com.company;
import javax.xml.crypto.Data;
import java.io.*;
import java.net.Socket;
//Client
public class Client extends Socket{
private final String SERVER_IP="192.168.201.104";
private final int SERVER_PORT=8999;
private Socket client;
private FileInputStream fis;
private DataOutputStream dos;
//Create a client and specify the IP and port number of the received server
public Client() throws IOException{
this.client=new Socket(SERVER_IP,SERVER_PORT);
System.out.println("Successfully connected to the server..."+SERVER_IP);
}
//Transfer files to the server
public void sendFile(String url) throws IOException {
File file=new File(url);
try {
fis = new FileInputStream(file);
//BufferedInputStream bi=new BufferedInputStream(new InputStreamReader(new FileInputStream(file),"GBK"));
dos = new DataOutputStream(client.getOutputStream());//client.getOutputStream() returns the output stream of this socket
//File name, size and other attributes
dos.writeUTF(file.getName());
dos.flush();
dos.writeLong(file.length());
dos.flush();
// Start file transfer
System.out.println("======== Start file transfer ========");
byte[] bytes = new byte[1024];
int length = 0;
while ((length = fis.read(bytes, 0, bytes.length)) != -1) {
dos.write(bytes, 0, length);
dos.flush();
}
System.out.println("======== File transfer successful ========");
}catch(IOException e){
e.printStackTrace();
System.out.println("Client file transfer exception");
}finally{
fis.close();
dos.close();
}
}
public static void main(String[] args) {
try {
Client client = new Client(); // Start client connection
client.sendFile("E:/dxn/aaa.txt"); // transfer files
} catch (Exception e) {
e.printStackTrace();
}
}
}
2 server side
Start the server new ServerSocket(port)
Receive the client object connecting to the server
Create an input stream to return to the socket
Create file output stream write out file
Read article name, length and other attributes
Read and write articles
Closed flow
package com.company;
import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;
public class FileServer extends ServerSocket{
private static final int SERVER_PORT = 8999; // Server port
private ServerSocket server;
private Socket socket;
private DataInputStream dis;
private FileOutputStream fos;
public FileServer() throws Exception {
server=new ServerSocket(SERVER_PORT);
}
public void task() throws IOException{
System.out.println("======== Waiting for connection ========");
Socket socket = server.accept();
System.out.println(" Ip:"+socket.getInetAddress()+"Connected");
try {
dis = new DataInputStream(socket.getInputStream());
// File name and length
String fileName = dis.readUTF();
long fileLength = dis.readLong();
File directory = new File("E:/a");
if(!directory.exists()) {
directory.mkdir();
}
File file = new File(directory.getAbsolutePath() + File.separatorChar + fileName);
fos = new FileOutputStream(file);
System.out.println("file. . . . . . . . . . . . . . "+file);
System.out.println("fileName. . . . . . . . . . . . . . "+fileName);
System.out.println("======== Start receiving files ========");
byte[] bytes = new byte[1024];
int length = 0;
while((length = dis.read(bytes, 0, bytes.length)) != -1) {
fos.write(bytes, 0, length);
fos.flush();
}
System.out.println("======== File received successfully ========");
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
if(fos != null)
fos.close();
if(dis != null)
dis.close();
socket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
public static void main(String[] args) {
try {
FileServer server = new FileServer(); // Start server
server.task();
} catch (Exception e) {
e.printStackTrace();
}
}
}
3. Every time a Socket is received, a new thread is created to handle it
package com.company;
import java.io.DataInputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.net.ServerSocket;
import java.net.Socket;
public class Server extends ServerSocket {
private static final int SERVER_PORT = 8999; // Server port
private ServerSocket server;
public Server() throws Exception {
server=new ServerSocket(SERVER_PORT);
}
/**
* Use threads to process files transferred by each client
* @throws Exception
*/
public void load() throws Exception {
while (true) {
System.out.println("-----------Waiting for connection-------- ");
Socket socket = server.accept();//Receive the client object connecting to the server
System.out.println("ip" + socket.getInetAddress() + "Connected");
new Thread(new Transfer(socket),"thread1").start();// Every time a Socket is received, a new thread is created to handle it
System.out.println(Thread.currentThread().getName());
}
}
/**
* Handle the file thread class transferred from the client
*/
class Transfer implements Runnable {
private Socket socket;
private DataInputStream dis;
private FileOutputStream fos;
public Transfer(Socket socket) {
this.socket = socket;
}
@Override
public void run() {
try {
dis = new DataInputStream(socket.getInputStream());
// File name and length
String fileName = dis.readUTF();
long fileLength = dis.readLong();
File directory = new File("E:/xn");
if(!directory.exists()) {
directory.mkdir();
}
File file = new File(directory.getAbsolutePath() + File.separatorChar + fileName);
System.out.println("file"+file);
fos = new FileOutputStream(file);
// Start receiving files
byte[] bytes = new byte[1024];
int length = 0;
while((length = dis.read(bytes, 0, bytes.length)) != -1) {
fos.write(bytes, 0, length);
fos.flush();
}
System.out.println("======== File received successfully [File Name: " + fileName + "] ");
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
if(fos != null)
fos.close();
if(dis != null)
dis.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
public static void main(String[] args) {
try {
Server server = new Server(); // Start server
server.load();
} catch (Exception e) {
e.printStackTrace();
}
}
}
4.DataInputStream: read basic Java data type from data input stream
DataOutputStream: data output stream writes out basic Java data types