Java网络编程

使用Java网络编程实现用户上传文件

1. 客户端Client:
   用户上传本地文件到服务器端，服务器返回文件上传成功。

   package xnj.fileupload;
   
   import java.io.*;
   import java.net.InetAddress;
   import java.net.Socket;
   import java.util.concurrent.*;
   
   // 客户端;上传文件
   public class Client {
       public static void main(String[] args) throws IOException {
           // 创建socket对象连接服务器,服务器ip地址和端口
           Socket socket = new Socket("127.0.0.1",10086);
   
           // 读取本地文件并写入服务器
           FileInputStream fis = new FileInputStream("C:\\Users\\xnj\\Pictures\\保存的图片\\1594086267611.jpg");
           BufferedInputStream bis = new BufferedInputStream(fis);
           BufferedOutputStream bos = new BufferedOutputStream(socket.getOutputStream());
           byte[] bytes = new byte[1024];
           int len;
           while( ( len = bis.read(bytes)) != -1){
               bos.write(bytes,0,len);
           }
   
           // 往服务器发送结束标记
           socket.shutdownOutput();
   
           // 接收服务器的响应信息
           BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream()));
           String msg = br.readLine();
           System.out.println(msg);
   
           // 关闭资源
           socket.close();
       }
   }

2. 服务端Server:
   服务器端接收客户端上传的文件，并保存到服务器本地。

   package xnj.fileupload;
   
   import java.io.*;
   import java.net.ServerSocket;
   import java.net.Socket;
   import java.util.UUID;
   import java.util.concurrent.ArrayBlockingQueue;
   import java.util.concurrent.Executors;
   import java.util.concurrent.ThreadPoolExecutor;
   import java.util.concurrent.TimeUnit;
   
   // 服务端，保存客户端上传的文件
   public class Server {
   
       public static void main(String[] args) throws IOException {
           // 下面频繁创建线程会消耗服务器的性能，所以这里使用线程池
           ThreadPoolExecutor pool = new ThreadPoolExecutor(
                   3,// 核心线程数
                   16,// 最大线程数
                   60,// 线程空闲时间
                   TimeUnit.SECONDS,// 线程空闲时间单位
                   new ArrayBlockingQueue<Runnable>(2),// 阻塞队列
                   Executors.defaultThreadFactory(),// 线程工厂,让工厂如何创建线程对象
                   new ThreadPoolExecutor.AbortPolicy()// 拒绝策略
           );
   
   
           // 创建对象,监听10000端口
           ServerSocket serverSocket = new ServerSocket(10086);
   
           // 循环监听，即可多次上传
           while (true) {
               // 等待客户端连接
               Socket socket  = serverSocket.accept();
   
               // 开启一条线程
               // 一个用户对应一条线程
               // new MyRunnable(socket).start();
               // 使用线程池
               pool.submit(new MyRunnable(socket));
           }
   
       }
   }

3. 线程类MyRunnable:

   package xnj.fileupload;
   
   import java.io.*;
   import java.net.Socket;
   import java.util.UUID;
   
   public class MyRunnable implements Runnable{
   
       Socket socket ;
   
       public MyRunnable(Socket socket) {
           this.socket = socket;
       }
       @Override
       public void run() {
           try {
               // 读取数据并保存到本地文件中
               BufferedInputStream bis = new BufferedInputStream(socket.getInputStream());
               String name = UUID.randomUUID().toString().replace("-", "");
               BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream("fileimage\\"+name+".jpg"));
               byte[] bytes = new byte[1024];
               int len;
               while( ( len = bis.read(bytes)) != -1){
                   bos.write(bytes,0,len);
               }
   
               // 发送反馈信息
               socket.shutdownInput();
               BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));
               bw.write("上传成功");
               bw.newLine();
               bw.flush();
   
           } catch (IOException e) {
               throw new RuntimeException(e);
           }finally {
               // 释放资源
               if(socket != null){
                   try {
                       socket.close();
                   } catch (IOException e) {
                       throw new RuntimeException(e);
                   }
               }
           }
       }
   }