Java NIO 简单例子

服务器端：

package nioT;import java.io.IOException;import java.net.InetSocketAddress;import java.nio.ByteBuffer;import java.nio.channels.SelectionKey;import java.nio.channels.Selector;import java.nio.channels.ServerSocketChannel;import java.nio.channels.SocketChannel;import java.nio.charset.Charset;import java.util.Iterator;public class NIOServer1 {// 本地字符集private static final String LocalCharSetName = "UTF-8";// 本地服务器监听的端口private static final int Listenning_Port = 8888;// 缓冲区大小private static final int Buffer_Size = 1024;// 超时时间,单位毫秒private static final int TimeOut = 3000;public static void main(String[] args) throws IOException {// 创建一个在本地端口进行监听的服务Socket信道.并设置为非阻塞方式ServerSocketChannel serverChannel = ServerSocketChannel.open();serverChannel.socket().bind(new InetSocketAddress(Listenning_Port));serverChannel.configureBlocking(false);// 创建一个选择器并将serverChannel注册到它上面Selector selector = Selector.open();serverChannel.register(selector, SelectionKey.OP_ACCEPT);while (true) {// 等待某个信道就绪if (selector.select(TimeOut) == 0) {System.out.println(".");continue;}// 获得就绪信道的键迭代器Iterator<SelectionKey> keyIter = selector.selectedKeys().iterator();// 使用迭代器进行遍历就绪信道while (keyIter.hasNext()) {SelectionKey key = keyIter.next();// 这种情况是有客户端连接过来,准备一个clientChannel与之通信if (key.isAcceptable()) {SocketChannel clientChannel = ((ServerSocketChannel) key.channel()).accept();clientChannel.configureBlocking(false);clientChannel.register(selector, SelectionKey.OP_READ,ByteBuffer.allocate(Buffer_Size));}// 客户端有写入时if (key.isReadable()) {// 获得与客户端通信的信道SocketChannel clientChannel = (SocketChannel) key.channel();// 得到并重置缓冲区的主要索引值ByteBuffer buffer = (ByteBuffer) key.attachment();buffer.clear();// 读取信息获得读取的字节数long bytesRead = clientChannel.read(buffer);if (bytesRead == -1) {// 没有读取到内容的情况clientChannel.close();} else {// 将缓冲区准备为数据传出状态buffer.flip();// 将获得字节字符串(使用Charset进行解码)String receivedString = Charset.forName(LocalCharSetName).newDecoder().decode(buffer).toString();// 控制台打印出来System.out.println("接收到信息:" + receivedString);// 准备发送的文本String sendString = "你好,客户端. 已经收到你的信息" + receivedString;// 将要发送的字符串编码(使用Charset进行编码)后再进行包装buffer = ByteBuffer.wrap(sendString.getBytes(LocalCharSetName));// 发送回去clientChannel.write(buffer);// 设置为下一次读取或是写入做准备key.interestOps(SelectionKey.OP_READ | SelectionKey.OP_WRITE);}}keyIter.remove();}}}}

客户端：

package nioT;import java.io.IOException;import java.io.InputStream;import java.io.OutputStream;import java.io.PrintWriter;import java.net.Socket;import java.net.UnknownHostException;import java.util.Scanner;public class NIOClient1Test {public static void main(String[] args) throws UnknownHostException,IOException {Socket s = new Socket("localhost", 8888);InputStream inStream = s.getInputStream();OutputStream outStream = s.getOutputStream();// 输出PrintWriter out = new PrintWriter(outStream, true);out.println("getPublicKey你好！");out.flush();s.shutdownOutput();// 输出结束// 输入Scanner in = new Scanner(inStream);StringBuilder sb = new StringBuilder();while (in.hasNextLine()) {String line = in.nextLine();sb.append(line);}String response = sb.toString();System.out.println("response=" + response);}}

运行结果

服务端：

.接收到信息:getPublicKey你好！.

客户端：

response=你好,客户端. 已经收到你的信息getPublicKey你好！