山寨web服务器

清疚 2022-07-28 09:57 177阅读 0赞

这是及其简单的web服务器，只实现从请求到处理请求的过程。基本架构如下

![这里写图片描述][20160414154028395]

主程序：使用socket监听端口，等待用户连接，一旦有用户连接，创建一个线程放入线程池。代码如下：

package com.web.tomdog;
    
    import java.io.IOException;
    import java.net.ServerSocket;
    import java.net.Socket;
    import java.util.concurrent.ExecutorService;
    import java.util.concurrent.Executors;
    
    public class Tomdog { 
    
        public static void main(String[] args) {
            new Tomdog().start();
    
        }
        /** * 启动服务器 */
        public void start(){
            try {
                //启动服务
                ServerSocket ss = new ServerSocket(Properties.PORT);
                System.out.println("服务器启动....端口："+Properties.PORT);
                while(true){
                    //等待连接
                    Socket socket = ss.accept();
                    //一旦有连接，使用并发量100的线程池处理请求
                    ExecutorService pool = Executors.newFixedThreadPool(100);
                    pool.submit(new RequestHandlerThread(socket));
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    
    }

处理请求的线程：使用IO流，读取用户想要访问的资源，然后输出给用户

package com.web.tomdog;
    
    import java.io.BufferedInputStream;
    import java.io.File;
    import java.io.FileInputStream;
    import java.io.IOException;
    import java.io.PrintStream;
    import java.net.Socket;
    
    public class RequestHandlerThread implements Runnable{ 
    
        private HttpRequest request = null;
        private HttpResponse response = null;
    
    
        public RequestHandlerThread(Socket socket) {
            request = new HttpRequest(socket);
            response = new HttpResponse(socket);
        }
    
        @Override
        public void run() {
            String url = request.getRequestUrl();
            File file = new File(Properties.WEB_ROOT+url);
    
            PrintStream out = response.getWriter();
    
            if (file.exists()) {
                try {
                    //根据用户请求的路径，读取文件
                    byte[] bs = new byte[(int)file.length()];
                    BufferedInputStream bis = new BufferedInputStream(new FileInputStream(file));
                    bis.read(bs);
                    //将文件输出给用户
                    //使用println输出状态，使用write输出内容
                    out.println(Properties.STATUS_200);
                    //必须换行，否则浏览器无法解析
                    out.println();
                    out.write(bs);
                    out.flush();
                    out.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }else{
       //找不到资源，返回404
                out.println(Properties.STATUS_404);
                out.println();
                try {
                    out.write("<h1>404 ERROR...</h1>".getBytes());
                    out.flush();
                    out.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
    
            }
        }
    
    }

封装request和response

package com.web.tomdog;
    
    import java.io.BufferedReader;
    import java.io.IOException;
    import java.io.InputStream;
    import java.io.InputStreamReader;
    import java.net.Socket;
    
    public class HttpRequest { 
    
        private InputStream in = null;
    
        private String requestUrl;
    
        public HttpRequest(Socket socket) {
            try {
                in = socket.getInputStream();
                this.requestUrl = parseRequestUrl();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    
        public String getRequestUrl(){
            return this.requestUrl;
        }
    
        /** * 解析请求信息，得到访问路径 * @return */
        private String parseRequestUrl(){
            BufferedReader reader = new BufferedReader(new InputStreamReader(in));
            String url = "";
            try {
                String head = reader.readLine();
                System.out.println(head);
                if (head != null) {
                    url = head.split(" ")[1];
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
            if(url.equals("/")){
                url = Properties.INDEX;
            }
            return url;
        }
    
    
    }

package com.web.tomdog;
    
    import java.io.IOException;
    import java.io.PrintStream;
    import java.net.Socket;
    
    public class HttpResponse {
    
        private PrintStream out = null;
    
        public HttpResponse(Socket socket){
            try {
                out = new PrintStream(socket.getOutputStream());
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    
        public PrintStream getWriter(){
            return out;
        }
    }

自定义Properties类来替代读取配置文件的过程

package com.web.tomdog;
    
    import java.io.File;
    /** * 服务器配置信息（实际上应该从配置文件读取） * @author 周 * */
    public class Properties { 
        /** * 默认端口号 */
        public static final int PORT = 8080;
        /** * web资源文件根目录，相当于tomcat的webapps，此处指定为D:\webapps\ */
        public static final String WEB_ROOT = "D:"+File.separator+"webapps"+File.separator;
        /** * 默认页面，当访问/路径时，即访问index.html */
        public static final String INDEX = "/index.html";
        /** * 状态码200 */
        public static final String STATUS_200 = "HTTP/1.1 200 OK";
        /** * 状态码404 */
        public static final String STATUS_404 = "HTTP/1.1 404 NOT FOUND";
    }

在Properties 中定义的WEB\_ROOT目录下，放一些图片，文本，html，使用localhost:8080/xxx访问试试看

![这里写图片描述][20160414154756247]

![这里写图片描述][20160414154801764]

[20160414154028395]: /images/20220724/252ef8c30177401ea7d830af7ada24c6.png
[20160414154756247]: /images/20220724/196c3f7396aa475a9e9a8528cfe42e11.png
[20160414154801764]: /images/20220724/d4580d21f90a498b9673e0849c000e33.png