1.知识点：
- 使用Java实现简单的HTTP服务器端
- ServerSocket类和Socket类的使用
- StringTokenizer类的使用
- 多线程Thread
2.源代码：
import java.io.BufferedReader; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.OutputStream; import java.net.ServerSocket; import java.net.Socket; import java.util.StringTokenizer; public class httpServer { public static void main(String args[]) { int port = 9090; ServerSocket server_socket; try { // 监听服务器端口，等待连接请求 server_socket = new ServerSocket(port); System.out.println( "httpServer running on port " + server_socket.getLocalPort()); // 显示启动信息 while (true) { Socket socket = server_socket.accept(); System.out.println( "New connection accepted " + socket.getInetAddress() + ":" + socket.getPort()); // 创建分线程 try { httpRequestHandler request = new httpRequestHandler(socket); Thread thread = new Thread(request); // 启动线程 thread.start(); } catch (Exception e) { System.out.println(e); } } } catch (IOException e) { System.out.println(e); } } } class httpRequestHandler implements Runnable { final static String CRLF = "\r\n"; Socket socket; InputStream input; OutputStream output; BufferedReader br; // 构造方法 public httpRequestHandler(Socket socket) throws Exception { this.socket = socket; this.input = socket.getInputStream(); this.output = socket.getOutputStream(); this.br = new BufferedReader( new InputStreamReader(socket.getInputStream())); } // 实现Runnable 接口的run()方法 public void run() { try { processRequest(); } catch (Exception e) { System.out.println(e); } } private void processRequest() throws Exception { while (true) { // 读取并显示Web 浏览器提交的请求信息 String headerLine = br.readLine(); System.out.println( "The client request is " + headerLine); if (headerLine.equals(CRLF) || headerLine.equals( "")) break; StringTokenizer s = new StringTokenizer(headerLine); String temp = s.nextToken(); if (temp.equals( "GET")) { String fileName = s.nextToken(); fileName = "." + fileName; // 打开所请求的文件 FileInputStream fis = null; boolean fileExists = true; try { fis = new FileInputStream(fileName); } catch (FileNotFoundException e) { fileExists = false; } // 完成回应消息 String serverLine = "Server: a simple java httpServer"; String statusLine = null; String contentTypeLine = null; String entityBody = null; String contentLengthLine = "error"; if (fileExists) { statusLine = "HTTP/1.0 200 OK" + CRLF; contentTypeLine = "Content-type: " + contentType(fileName) + CRLF; contentLengthLine = "Content-Length: " + ( new Integer(fis.available())).toString() + CRLF; } else { statusLine = "HTTP/1.0 404 Not Found" + CRLF; contentTypeLine = "text/html"; entityBody = "＜HTML＞" + "＜HEAD＞＜TITLE＞404 Not Found＜/TITLE＞＜/HEAD＞" + "＜BODY＞404 Not Found" + "＜br＞usage:http://yourHostName:port/" + "fileName.html＜/BODY＞＜/HTML＞"; } // 发送到服务器信息 output.write(statusLine.getBytes()); output.write(serverLine.getBytes()); output.write(contentTypeLine.getBytes()); output.write(contentLengthLine.getBytes()); output.write(CRLF.getBytes()); // 发送信息内容 if (fileExists) { sendBytes(fis, output); fis.close(); } else { output.write(entityBody.getBytes()); } } } // 关闭套接字和流 try { output.close(); br.close(); socket.close(); } catch (Exception e) { } } private static void sendBytes(FileInputStream fis, OutputStream os) throws Exception { // 创建一个 1K buffer byte[] buffer = new byte[ 1024]; int bytes = 0; // 将文件输出到套接字输出流中 while ((bytes = fis.read(buffer)) != - 1) { os.write(buffer, 0, bytes); } } private static String contentType(String fileName) { if (fileName.endsWith( ".htm") || fileName.endsWith( ".html")) { return "text/html"; } return "fileName"; } }
目录结构：项目根目录下放一个HTML文件
3.测试结果：
运行程序，服务器启动了，然后打开浏览器，输入地址：
控制台输出：
