package cn.upload;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintStream;
import java.net.ServerSocket;
import java.net.Socket;

public class UploadServer {

	
	public static void main(String[] args) throws Exception {
		System.out.println("服务器已启动, 绑定12345端口.");
		
		ServerSocket serverSocket = new ServerSocket(12345);
		while(true){
			final Socket socket=serverSocket.accept();
			new Thread(){
				public void run() {
					try {
						// 3.读取文件名
						// 字节流可以读写各种类型的数据
						InputStream is = socket.getInputStream();		
						// 字符流只能读字符
						BufferedReader br = new BufferedReader(new InputStreamReader(is));		
						PrintStream ps = new PrintStream(socket.getOutputStream());
						String filename = br.readLine();
						
						// 3.1.读取文件大小
						long length = Long.parseLong(br.readLine());
						
						// 4.判断文件是否存在, 将结果发回客户端
						File dir = new File("upload");
						dir.mkdir();
						File file = new File(dir, filename);
						// 文件存在, 大小一致代表已上传过了
						if (file.exists() && file.length() == length) {		
							ps.println("存在");
							socket.close();
							return;
						} else {
							// 不存在是0, 存在则是传了一半的大小
							ps.println(file.length());						
						}
						
						String ip = socket.getInetAddress().getHostAddress();
						System.out.println(ip + (file.exists() ? "断点续传:" : "开始上传: ") + file.getName());
						long start = System.currentTimeMillis();
						
						// 7.定义FileOutputStream, 从网络读取数据, 存储到本地
						FileOutputStream fos = new FileOutputStream(file, true);
						byte[] buffer = new byte[1024];
						int len;
						// 文件可能是任意类型, 所以使用字节流读取
						while ((len = is.read(buffer)) != -1)		
							fos.write(buffer, 0, len);
						fos.close();
						socket.close();
						
						long end = System.currentTimeMillis();
						System.out.println(ip + "上传完毕: " + file.getName() + ", 耗时: " + (end - start) + "毫秒.");
					} catch (IOException e) {
						e.printStackTrace();
					}
				}
			}.start();
		}
	}

}