通过SOCKET实现文件下载

import java.io.BufferedInputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Scanner;

public class FunctionServer {

private static int PORT = 2012;
private String path = "需要下载的文件所在路径";

public static void main(String[] args) throws IOException{
FunctionServer server = new FunctionServer();
server.start();
}
public void start() throws IOException{
ServerSocket ss = new ServerSocket(PORT);
while(true){

Socket s = ss.accept();
new Service(s).start();//创建线程
}
}
class Service extends Thread{
Socket s;
public Service(Socket s){
this.s = s;
}
public void run(){
try{
InputStream in = s.getInputStream();//得到输入流
Scanner sc = new Scanner(in);
OutputStream out = s.getOutputStream();

while(true){
String str = sc.nextLine();//读取文件名
if(!str.equals(null)){
System.out.println("你的文件名是"+str);
//根据路径和文件名获取文件
File f = new File(path+str);
FileInputStream fis = new FileInputStream(f);

DataInputStream dis = new DataInputStream(new BufferedInputStream(fis));
byte[] buffer  = new byte[8192];
DataOutputStream ps = new DataOutputStream(out);
ps.writeLong((long) f.length());//发送文件大小
ps.flush();
while(true) {
int read = 0;
if(dis!=null){
read = fis.read(buffer);
}
if(read == -1){
break;
}
ps.write(buffer,0,read);
}
ps.flush();
dis.close();
s.close();
out.flush();
break;
}
}
}catch(IOException e){
e.printStackTrace();
}

}
}
}

class DownloadThread extends Thread {
Socket socket;
InputStream in;
OutputStream out;
String path = "文件保存路径";
String functionName;
String serverIp = "服务器IP";
int socketPort = "服务端口号";

int fileSize,downLoadFileSize;

public DownloadThread(String functionName) {
this.functionName = functionName;
}

@Override
public void run() {
Looper.prepare();
while(!Thread.interrupted()){
try {
socket = new Socket(serverIp, socketPort);

InputStream in = socket.getInputStream();
OutputStream out = socket.getOutputStream();

out.write((functionName + "\n").getBytes("gbk"));
out.flush(); // 清理缓冲，确保发送到服务端

File f = new File(path + functionName);
OutputStream song = new FileOutputStream(f);

DataInputStream dis = new DataInputStream(
new BufferedInputStream(in));
DataOutputStream dos = new DataOutputStream(
new BufferedOutputStream(song));
fileSize = (int) dis.readLong() - 1;
System.out.println("开始下载");
byte[] buffer = new byte[8192];
while (true) {
int read = 0;
if (dis != null) {
read = dis.read(buffer);
downLoadFileSize += read;

}
if (read == -1) {
break;
}
dos.write(buffer, 0, read);
}
System.out.println("文件下载完成");
dos.close();
} catch (UnknownHostException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
this.interrupt();
}
}
}
}