使用 ServerSocketChannel 实现的 File 服务器

import java.nio.channels.*;
import java.nio.charset.*;
import java.net.*;
import java.io.*;
import java.util.*;
import java.nio.*;

public class FileServer {
private int port = 8050;

private ServerSocketChannel serverSocketChannel;

private Charset charset = Charset.forName("GBK");

private Selector selector = null;

public FileServer() throws IOException {
selector = Selector.open();
serverSocketChannel = ServerSocketChannel.open();
serverSocketChannel.socket().setReuseAddress(true);
serverSocketChannel.socket().bind(new InetSocketAddress(port));
System.out.println("服务器启动");
}

/* 编码过程 */
public ByteBuffer encode(String str) {
return charset.encode(str);
}

/* 解码过程 */
public String decode(ByteBuffer bb) {
return charset.decode(bb).toString();
}

/* 服务器服务方法 */
public void service() throws IOException {
serverSocketChannel.configureBlocking(false);
serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);
/** 外循环，已经发生了SelectionKey数目 */
while (selector.select() > 0) {
/* 得到已经被捕获了的SelectionKey的集合 */
Iterator iterator = selector.selectedKeys().iterator();
while (iterator.hasNext()) {
SelectionKey key = null;
try {
key = (SelectionKey) iterator.next();
iterator.remove();
if (key.isAcceptable()) {
ServerSocketChannel ssc = (ServerSocketChannel) key.channel();
SocketChannel sc = ssc.accept();
System.out.println("客户端机子的地址是 " + sc.socket().getLocalAddress() + " 客户端机机子的端口号是 " + sc.socket().getLocalPort());
sc.configureBlocking(false);
ByteBuffer buffer = ByteBuffer.allocate(1024);
sc.register(selector, SelectionKey.OP_READ | SelectionKey.OP_WRITE, buffer);
}
if (key.isReadable()) {
reveice(key);
}
if (key.isWritable()) {
send(key);
}
} catch (IOException e) {
e.printStackTrace();
try {
if (key != null) {
key.cancel();
key.channel().close();
}
} catch (ClosedChannelException cex) {
e.printStackTrace();
}
}
}
/* 内循环完 */
}
/* 外循环完 */
}

/* service方法完 */
public void reveice(SelectionKey key) throws IOException {
if (key == null)
return;
ByteBuffer buff = (ByteBuffer) key.attachment();
SocketChannel sc = (SocketChannel) key.channel();
buff.limit(buff.capacity());
buff.position(0);
sc.read(buff);
buff.flip();
String reviceData = decode(buff);
}

/* 发送文件 */
public void send(SelectionKey key) {
if (key == null)
return;
ByteBuffer buff = (ByteBuffer) key.attachment();
SocketChannel sc = (SocketChannel) key.channel();
String data = decode(buff);
if (data.indexOf("get") == -1)
return;
String subStr = data.substring(data.indexOf(" "), data.length());
System.out.println("截取之后的字符串是 " + subStr);
FileInputStream fileInput = null;
try {
fileInput = new FileInputStream(subStr);
FileChannel fileChannel = fileInput.getChannel();
fileChannel.transferTo(0, fileChannel.size(), sc);
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
fileInput.close();
} catch (IOException ex) {
ex.printStackTrace();
}
}
}

public static void main(String[] args) throws IOException {
new FileServer().service();
}
}