http是应用层的一种协议，我们浏览器就是基于http协议，写个例子以后供参考。
package com.tomcat.test; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.io.OutputStreamWriter; import java.io.PrintWriter; import java.io.UnsupportedEncodingException; import java.net.ServerSocket; import java.net.Socket; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; public class TestMain { private static ServerSocket serverSocket; private static ExecutorService executorService; private final static int POOL_SIZE = 100; //以下是一个http请求响应的小例子，tomcat就是在此基础上进行的，只不过tomcat进一步解析了web.xml public static void main(String[] args) throws UnsupportedEncodingException, IOException { serverSocket = new ServerSocket(8089); executorService = Executors.newFixedThreadPool(POOL_SIZE); executorService.execute(new Runnable() { @Override public void run() { Socket socket = null; while (true) { try { socket = serverSocket.accept(); //socket的输入流其实就是请求的信息 //这里会有个比较奇葩的问题，就是如果不把socket的InputStream从内存中read出来，谷歌浏览器会出现问题 //因为每次谷歌浏览器请求会多发一次请求获取favicon.ico，如自动发送http://127.0.0.1:8089/favicon.ico //这个请求就是请求浏览器地址栏最左边的小图标 //如果不read出来会出现阻塞现象，导致favicon.ico请求写不进内存，从而刷新页面有时会出错，无法响应请求 //火狐和IE暂时没有发现这个奇葩问题 BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream())); StringBuffer httpReqStr = new StringBuffer(""); int rlength; char[] chars = new char[100]; rlength = reader.read(chars); while(rlength == 100){ httpReqStr.append(chars); chars = new char[100]; rlength = reader.read(chars); } httpReqStr.append(chars); System.out.println(httpReqStr);//获取请求(包括请求信息以及请求头) } catch (IOException e) { e.printStackTrace(); } PrintWriter writer; try { writer = new PrintWriter(new OutputStreamWriter(socket.getOutputStream(), "UTF-8")); writer.println("HTTP/1.1 200 OK");//响应状态行 writer.println("Content-Type: text/html;charset=UTF-8");//响应格式行 writer.println("");//空行 //下面响应体 writer.println("<!DOCTYPE html>"); writer.println("<html>"); writer.println("Welcome to my HttpTest!!"); writer.println("</html>"); writer.flush(); writer.close(); } catch (UnsupportedEncodingException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } //其实wirter关了，socket也关了 try { socket.close(); } catch (IOException e) { e.printStackTrace(); } try { Thread.sleep(10); } catch (InterruptedException e) { e.printStackTrace(); } } } }); } } 启动后相当于一个小小的服务器，下面为结果截图：1.控制台获取的请求信息
2.谷歌浏览器的结果
