Java使用Socket通信传输文件的方法示例

本文实例讲述了java使用socket通信传输文件的方法。分享给大家供大家参考，具体如下：

前面几篇文章介绍了使用java的socket编程和nio包在socket中的应用，这篇文章说说怎样利用socket编程来实现简单的文件传输。

这里由于前面一片文章介绍了nio在socket中的应用，所以这里在读写文件的时候也继续使用nio包，所以代码看起来会比直接使用流的方式稍微复杂一点点。

下面的示例演示了客户端向服务器端发送一个文件，服务器作为响应给客户端回发一个文件。这里准备两个文件e:/test/server_send.log和e:/test/client.send.log文件，在测试完毕后在客户端和服务器相同目录下会多出两个文件e:/test/server_receive.log和e:/test/client.receive.log文件。

下面首先来看看server类，主要关注其中的sendfile和receivefile方法。

package com.googlecode.garbagecan.test.socket.nio;
import java.io.file;
import java.io.fileinputstream;
import java.io.fileoutputstream;
import java.io.ioexception;
import java.net.inetsocketaddress;
import java.nio.bytebuffer;
import java.nio.channels.closedchannelexception;
import java.nio.channels.filechannel;
import java.nio.channels.selectionkey;
import java.nio.channels.selector;
import java.nio.channels.serversocketchannel;
import java.nio.channels.socketchannel;
import java.util.iterator;
import java.util.logging.level;
import java.util.logging.logger;
public class myserver4 {
  private final static logger logger = logger.getlogger(myserver4.class.getname());
  public static void main(string[] args) {
    selector selector = null;
    serversocketchannel serversocketchannel = null;
    try {
      // selector for incoming time requests
      selector = selector.open();
      // create a new server socket and set to non blocking mode
      serversocketchannel = serversocketchannel.open();
      serversocketchannel.configureblocking(false);
      // bind the server socket to the local host and port
      serversocketchannel.socket().setreuseaddress(true);
      serversocketchannel.socket().bind(new inetsocketaddress(10000));
      // register accepts on the server socket with the selector. this
      // step tells the selector that the socket wants to be put on the
      // ready list when accept operations occur, so allowing multiplexed
      // non-blocking i/o to take place.
      serversocketchannel.register(selector, selectionkey.op_accept);
      // here's where everything happens. the select method will
      // return when any operations registered above have occurred, the
      // thread has been interrupted, etc.
      while (selector.select() > 0) {
        // someone is ready for i/o, get the ready keys
        iterator<selectionkey> it = selector.selectedkeys().iterator();
        // walk through the ready keys collection and process date requests.
        while (it.hasnext()) {
          selectionkey readykey = it.next();
          it.remove();
          // the key indexes into the selector so you
          // can retrieve the socket that's ready for i/o
          doit((serversocketchannel) readykey.channel());
        }
      }
    } catch (closedchannelexception ex) {
      logger.log(level.severe, null, ex);
    } catch (ioexception ex) {
      logger.log(level.severe, null, ex);
    } finally {
      try {
        selector.close();
      } catch(exception ex) {}
      try {
        serversocketchannel.close();
      } catch(exception ex) {}
    }
  }
  private static void doit(final serversocketchannel serversocketchannel) throws ioexception {
    socketchannel socketchannel = null;
    try {
      socketchannel = serversocketchannel.accept();
      receivefile(socketchannel, new file("e:/test/server_receive.log"));
      sendfile(socketchannel, new file("e:/test/server_send.log"));
    } finally {
      try {
        socketchannel.close();
      } catch(exception ex) {}
    }
  }
  private static void receivefile(socketchannel socketchannel, file file) throws ioexception {
    fileoutputstream fos = null;
    filechannel channel = null;
    try {
      fos = new fileoutputstream(file);
      channel = fos.getchannel();
      bytebuffer buffer = bytebuffer.allocatedirect(1024);
      int size = 0;
      while ((size = socketchannel.read(buffer)) != -1) {
        buffer.flip();
        if (size > 0) {
          buffer.limit(size);
          channel.write(buffer);
          buffer.clear();
        }
      }
    } finally {
      try {
        channel.close();
      } catch(exception ex) {}
      try {
        fos.close();
      } catch(exception ex) {}
    }
  }
  private static void sendfile(socketchannel socketchannel, file file) throws ioexception {
    fileinputstream fis = null;
    filechannel channel = null;
    try {
      fis = new fileinputstream(file);
      channel = fis.getchannel();
      bytebuffer buffer = bytebuffer.allocatedirect(1024);
      int size = 0;
      while ((size = channel.read(buffer)) != -1) {
        buffer.rewind();
        buffer.limit(size);
        socketchannel.write(buffer);
        buffer.clear();
      }
      socketchannel.socket().shutdownoutput();
    } finally {
      try {
        channel.close();
      } catch(exception ex) {}
      try {
        fis.close();
      } catch(exception ex) {}
    }
  }
}

下面是client程序代码，也主要关注sendfile和receivefile方法

package com.googlecode.garbagecan.test.socket.nio;
import java.io.file;
import java.io.fileinputstream;
import java.io.fileoutputstream;
import java.io.ioexception;
import java.net.inetsocketaddress;
import java.net.socketaddress;
import java.nio.bytebuffer;
import java.nio.channels.filechannel;
import java.nio.channels.socketchannel;
import java.util.logging.level;
import java.util.logging.logger;
public class myclient4 {
  private final static logger logger = logger.getlogger(myclient4.class.getname());
  public static void main(string[] args) throws exception {
    new thread(new myrunnable()).start();
  }
  private static final class myrunnable implements runnable {
    public void run() {
      socketchannel socketchannel = null;
      try {
        socketchannel = socketchannel.open();
        socketaddress socketaddress = new inetsocketaddress("localhost", 10000);
        socketchannel.connect(socketaddress);
        sendfile(socketchannel, new file("e:/test/client_send.log"));
        receivefile(socketchannel, new file("e:/test/client_receive.log"));
      } catch (exception ex) {
        logger.log(level.severe, null, ex);
      } finally {
        try {
          socketchannel.close();
        } catch(exception ex) {}
      }
    }
    private void sendfile(socketchannel socketchannel, file file) throws ioexception {
      fileinputstream fis = null;
      filechannel channel = null;
      try {
        fis = new fileinputstream(file);
        channel = fis.getchannel();
        bytebuffer buffer = bytebuffer.allocatedirect(1024);
        int size = 0;
        while ((size = channel.read(buffer)) != -1) {
          buffer.rewind();
          buffer.limit(size);
          socketchannel.write(buffer);
          buffer.clear();
        }
        socketchannel.socket().shutdownoutput();
      } finally {
        try {
          channel.close();
        } catch(exception ex) {}
        try {
          fis.close();
        } catch(exception ex) {}
      }
    }
    private void receivefile(socketchannel socketchannel, file file) throws ioexception {
      fileoutputstream fos = null;
      filechannel channel = null;
      try {
        fos = new fileoutputstream(file);
        channel = fos.getchannel();
        bytebuffer buffer = bytebuffer.allocatedirect(1024);
        int size = 0;
        while ((size = socketchannel.read(buffer)) != -1) {
          buffer.flip();
          if (size > 0) {
            buffer.limit(size);
            channel.write(buffer);
            buffer.clear();
          }
        }
      } finally {
        try {
          channel.close();
        } catch(exception ex) {}
        try {
          fos.close();
        } catch(exception ex) {}
      }
    }
  }
}

首先运行myserver4类启动监听，然后运行myclient4类来向服务器发送文件以及接受服务器响应文件。运行完后，分别检查服务器和客户端接收到的文件。

更多关于java相关内容感兴趣的读者可查看本站专题：《java socket编程技巧总结》、《java文件与目录操作技巧汇总》、《java数据结构与算法教程》、《java操作dom节点技巧总结》和《java缓存操作技巧汇总》

希望本文所述对大家java程序设计有所帮助。