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Java 实现HTTP协议

2017-10-23 17:32 357 查看

实例

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 HttpServer {

public static void main(String[] args) throws Exception {
// 创建ServerSocketChannel，监听8080端口
ServerSocketChannel ssc = ServerSocketChannel.open();
ssc.socket().bind(new InetSocketAddress(8080));
// 设置为非阻塞模式
ssc.configureBlocking(false);
// 为ssc注册选择器
Selector selector = Selector.open();
ssc.register(selector, SelectionKey.OP_ACCEPT);
// 创建处理器
while (true) {
// 等待请求，每次等待阻塞3s，超过3s后线程继续向下运行，如果传入0或者不传参数将一直阻塞
if (selector.select(3000) == 0) {
continue;
}
// 获取待处理的SelectionKey
Iterator<SelectionKey> keyIter = selector.selectedKeys().iterator();

while (keyIter.hasNext()) {
SelectionKey key = keyIter.next();
// 启动新线程处理SelectionKey
new Thread(new HttpHandler(key)).run();
// 处理完后，从待处理的SelectionKey迭代器中移除当前所使用的key
keyIter.remove();
}
}
}

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;
}

public void handleAccept() throws IOException {
SocketChannel clientChannel = ((ServerSocketChannel) key.channel()).accept();
clientChannel.configureBlocking(false);
clientChannel.register(key.selector(), SelectionKey.OP_READ, ByteBuffer.allocate(bufferSize));
}

public void handleRead() throws IOException {
// 获取channel
SocketChannel sc = (SocketChannel) key.channel();
// 获取buffer并重置
ByteBuffer buffer = (ByteBuffer) key.attachment();
buffer.clear();
// 没有读到内容则关闭
if (sc.read(buffer) == -1) {
sc.close();
} else {
// 接收请求数据
buffer.flip();
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();
sendString.append("HTTP/1.1 200 OK\r\n");//响应报文首行，200表示处理成功
sendString.append("Content-Type:text/html;charset=" + localCharset + "\r\n");
sendString.append("\r\n");// 报文头结束后加一个空行

sendString.append("<!DOCTYPE html>");
sendString.append("<html lang=\"en\">");
sendString.append("<head>");
sendString.append("    <meta charset=\"UTF-8\">");
sendString.append("    <title>Title</title>");
sendString.append("</head>");
sendString.append("<body>");
sendString.append("    <h4>hello world! </h4>");
sendString.append("</body>");
sendString.append("</html>");

buffer = ByteBuffer.wrap(sendString.toString().getBytes(localCharset));
sc.write(buffer);
sc.close();
}
}

@Override
public void run() {
try {
// 接收到连接请求时
if (key.isAcceptable()) {
handleAccept();
}
// 读数据
if (key.isReadable()) {
handleRead();
}
} catch (IOException ex) {
ex.printStackTrace();
}
}
}
}


测试

GET: http://localhost:8080

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标签：  java http协议
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