NioSocket实现HTTP协议

本文转自 拿客

NioSocket实现HTTP协议【基于Java Socket探究】

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;

/** * @author sanchan * @since 1.0 */
public class HttpServer {
    public static void main(String[] args) {
        /** * 启动监听 * 当监听到请求时根据SelectionKey的操作类型交给内部类Handler进行处理 */
        try {
            //创建ServerSocketChannel
            ServerSocketChannel ssc = ServerSocketChannel.open();
            //设置监听8080端口
            ssc.socket().bind(new InetSocketAddress(8080));
            //设置为非阻塞模式
            ssc.configureBlocking(false);
            //为ServerSocketChannel注册Selector
            Selector selector = Selector.open();
            ssc.register(selector, SelectionKey.OP_ACCEPT);
            while (true) {
                //等待请求,每次等待阻塞3s,超过3秒后线程继续运行,如果传入0或使用无参重载方法,将一直阻塞
                if (selector.select(3000) == 0) {
                    System.out.println("等待请求超时~~~~~");
                    continue;
                }
                System.out.println("处理请求~~~~~");
                //获取等待处理的SelectionKey
                Iterator<SelectionKey> keyIterator = selector.selectedKeys().iterator();
                while (keyIterator.hasNext()) {
                    SelectionKey key = keyIterator.next();
                    //启动新线程处理SelectionKey
                    new Thread(new HttpHandler(key)).run();
                    //处理完成删除请求
                    keyIterator.remove();
                    System.out.println("删除");
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
        }

    }

    /** * 请求处理类 */
    private static class HttpHandler implements Runnable {
        private int bufferSize = 1024;
        private String localCharset = "UTF-8";
        private SelectionKey key;

        public HttpHandler(SelectionKey key) {
            this.key = key;
        }


        /** * 处理请求操作 * * @param key * @throws IOException */
        public void handleAccept() throws IOException {
            //获取Channel
            SocketChannel sc = ((ServerSocketChannel) key.channel()).accept();
            //设置非阻塞
            sc.configureBlocking(false);
            //注册读操作的Selector
            sc.register(key.selector(), SelectionKey.OP_READ, ByteBuffer.allocate(bufferSize));
        }

        /** * 处理读操作 * * @param key * @throws IOException */
        public void handleRead() throws IOException {
            //获取Channel
            SocketChannel sc = ((SocketChannel) key.channel());
            //获取ByteBuffer
            ByteBuffer buffer = (ByteBuffer) key.attachment();
            //重置ByteBuffer。设置limit=capacity、position=0、mark=-1
            buffer.clear();
            //没有获取到内容则关闭
            if (sc.read(buffer) == -1) {
                sc.close();
            } else {
                buffer.flip();
                //返回数据到客户端
                String receivedString = Charset.forName(localCharset).newDecoder().decode(buffer).toString();
                //控制台打印请求报文头
                String[] requestMessage = receivedString.split("\r\n");
                for (String s : requestMessage) {
                    System.out.println(s);
                    //遇到空行说明报文头信息已经打印完
                    if (s.isEmpty()) {
                        break;
                    }
                }
                //控制台打印首行信息
                String[] firstLine = requestMessage[0].split(" ");
                System.out.println();
                System.out.println("Method:\t" + firstLine[0]);
                System.out.println("url:\t" + firstLine[1]);
                System.out.println("HTTP Version:\t" + firstLine[2]);
                System.out.println();
                //返回客户端
                StringBuilder sendString = new StringBuilder();
                //响应报文首行
                sendString.append("HTTP/1.1 200 OK\r\n");
                sendString.append("Content-Type:text/html;charset=" + localCharset + "\r\n");
                //响应报文头最后加一个空行
                sendString.append("\r\n");
                sendString.append("<!DOCTYPE html><html lang=\"en\"><head>");
                sendString.append("<meta charset=\"UTF-8\">");
                sendString.append("<title>显示报文</title>");
                sendString.append("</head>");
                sendString.append("<body>");
                sendString.append("接收到请求的报文是:<br/>");
                for (String s : requestMessage) {
                    sendString.append(s + "<br/>");
                }
                sendString.append("</body></html>");
                buffer = ByteBuffer.wrap(sendString.toString().getBytes(localCharset));
                sc.write(buffer);
                //关闭SocketChannel
                sc.close();
            }

        }

        @Override
        public void run() {
            try {
                if (key.isAcceptable()) {
                    handleAccept();
                }
                if (key.isReadable()) {
                    handleRead();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}