实现一个简单的Tomcat

落日映苍穹つ 2022-04-04 10:10 237阅读 0赞

Tomcat是目前市场上最流行的web server 之一,支持动态解析,提供socket服务,  
请求的分发等功能.  
下面分享下自己写的demo

package com.dongshuo;
    
    import java.io.IOException;
    import java.io.OutputStream;
    
    /**
     * @author :dongshuo
     * @date : 2018/12/16 13:02
     * @desc :
     */
    public class MyResponse {
        private OutputStream outputStream;
    
        public MyResponse(OutputStream outputStream) {
            this.outputStream = outputStream;
        }
    
        public void write(String content) throws IOException {
            StringBuffer httpResponse = new StringBuffer();
            httpResponse.append("HTTP/1.1 200 OK\n")
                    .append("Content-Type: text/html\n")
                    .append("\r\n")
                    .append("<html><meta http-equiv=\"content-type\" content=\"text/html; charset=utf-8\"><body>")
                    .append(content)
                    .append("</body</html>");
    
            outputStream.write(new String(httpResponse.toString().getBytes(),"UTF-8").getBytes());
            outputStream.close();
    
        }
    }

package com.dongshuo;
    
    import com.sun.deploy.net.HttpRequest;
    
    import java.io.IOException;
    import java.io.InputStream;
    
    /**
     * @author :dongshuo
     * @date : 2018/12/16 12:47
     * @desc :
     */
    public class MyRequest {
        private String url;
        private String method;
    
        public MyRequest(InputStream inputStream) throws IOException {
            String httpRequest = "";
            byte[] httpRequestBytes = new byte[1024];
            int length = 0;
            if ((length  = inputStream.read(httpRequestBytes)) > 0) {
                httpRequest = new String(httpRequestBytes , 0 , length);
            }
            String httpHead = httpRequest.split("\n")[0];
            url = httpHead.split("\\s")[1];
            method = httpHead.split("\\s")[0];
            System.out.println(this.toString());
        }
    
        @Override
        public String toString() {
            return "MyRequest{" +
                    "url='" + url + '\'' +
                    ", method='" + method + '\'' +
                    '}';
        }
    
        public String getUrl() {
            return url;
        }
    
        public void setUrl(String url) {
            this.url = url;
        }
    
        public String getMethod() {
            return method;
        }
    
        public void setMethod(String method) {
            this.method = method;
        }
    }

package com.dongshuo;
    
    /**
     * @author :dongshuo
     * @date : 2018/12/16 13:08
     * @desc :
     */
    public abstract class MyServlet {
        public abstract void doGet(MyRequest myRequest,MyResponse myResponse);
        public abstract void doPost(MyRequest myRequest,MyResponse myResponse);
    
        public void service(MyRequest myRequest,MyResponse myResponse) {
            if ("POST".equalsIgnoreCase(myRequest.getMethod())) {
                doPost(myRequest,myResponse);
            }else if ("GET".equalsIgnoreCase(myRequest.getMethod())) {
                doGet(myRequest,myResponse);
            }
        }
    }

package com.dongshuo;
    
    /**
     * @author :dongshuo
     * @date : 2018/12/16 13:15
     * @desc :
     */
    public class YouWillFindGirlServlet extends MyServlet {
        @Override
        public void doGet(MyRequest myRequest, MyResponse myResponse) {
            try {
                myResponse.write("method:GET 你今年一定会找到女朋友!");
            }catch (Exception e) {
                System.out.println(e);
            }
        }
    
        @Override
        public void doPost(MyRequest myRequest, MyResponse myResponse) {
            try {
                myResponse.write("method:POSt 你今年一定会找到女朋友!");
            }catch (Exception e) {
                System.out.println(e);
            }
        }
    }

package com.dongshuo;
    
    import java.io.IOException;
    
    /**
     * @author :dongshuo
     * @date : 2018/12/16 13:12
     * @desc :
     */
    public class YouWillSuccessServlet extends MyServlet {
        @Override
        public void doGet(MyRequest myRequest, MyResponse myResponse) {
            try {
                myResponse.write("method:GET 今年你一定会成功!");
            } catch (IOException e) {
                System.out.println(e);
            }
        }
    
        @Override
        public void doPost(MyRequest myRequest, MyResponse myResponse) {
            try {
                myResponse.write("method:POST 今年你一定会成功!");
            } catch (IOException e) {
                System.out.println(e);
            }
        }
    }

package com.dongshuo;
    
    /**
     * @author :dongshuo
     * @date : 2018/12/16 13:42
     * @desc :
     */
    public class ServletMapping {
        private String servletName;
        private String url;
        private String clazz;
    
        public ServletMapping(String servletName, String url, String clazz) {
            this.servletName = servletName;
            this.url = url;
            this.clazz = clazz;
        }
    
        public String getServletName() {
            return servletName;
        }
    
        public void setServletName(String servletName) {
            this.servletName = servletName;
        }
    
        public String getUrl() {
            return url;
        }
    
        public void setUrl(String url) {
            this.url = url;
        }
    
        public String getClazz() {
            return clazz;
        }
    
        public void setClazz(String clazz) {
            this.clazz = clazz;
        }
    }

package com.dongshuo;
    
    import java.util.ArrayList;
    import java.util.List;
    
    /**
     * @author :dongshuo
     * @date : 2018/12/16 13:43
     * @desc :
     */
    public class ServletMappingConfig {
        public static List<ServletMapping> servletMappingList = new ArrayList<>();
    
        static {
            servletMappingList.add(new ServletMapping("success","/success","com.dongshuo.YouWillSuccessServlet"));
            servletMappingList.add(new ServletMapping("findgirl","/findgirl","com.dongshuo.YouWillFindGirlServlet"));
        }
    }

package com.dongshuo;
    
    import java.io.IOException;
    import java.io.InputStream;
    import java.io.OutputStream;
    import java.net.ServerSocket;
    import java.net.Socket;
    import java.util.Map;
    import java.util.concurrent.ConcurrentHashMap;
    
    /**
     * @author :dongshuo
     * @date : 2018/12/16 13:57
     * @desc :
     */
    public class MyTomcat {
        private int port = 8080;
    
        private Map<String,String> urlServletMap = new ConcurrentHashMap<>();
    
        public MyTomcat(int port) {
            this.port = port;
        }
    
        private void initServletMapping() {
            for (ServletMapping servletMapping : ServletMappingConfig.servletMappingList) {
                urlServletMap.put(servletMapping.getUrl(),servletMapping.getClazz());
            }
        }
    
        public void start() {
            initServletMapping();
            ServerSocket serverSocket = null;
            try{
                serverSocket = new ServerSocket(port);
                System.out.println("MyTomcat is start..........");
                while (true) {
                    Socket socket = serverSocket.accept();
                    InputStream inputStream = socket.getInputStream();
                    OutputStream outputStream = socket.getOutputStream();
                    MyRequest myRequest = new MyRequest(inputStream);
                    MyResponse myResponse = new MyResponse(outputStream);
                    dispatch(myRequest,myResponse);
                    socket.close();
                }
            }catch (Exception e) {
                System.out.println(e);
            }finally {
                if (null != serverSocket) {
                    try {
                        serverSocket.close();
                    } catch (IOException e) {
                        System.out.println(e);
                    }
                }
            }
        }
    
        public void dispatch(MyRequest myRequest,MyResponse myResponse) {
            String clazz = urlServletMap.get(myRequest.getUrl());
            try {
                Class<MyServlet> myServletClass = (Class<MyServlet>)Class.forName(clazz);
                MyServlet myServlet = myServletClass.newInstance();
                myServlet.service(myRequest,myResponse);
            } catch (ClassNotFoundException e) {
                System.out.println(e);
            } catch (IllegalAccessException e) {
                System.out.println(e);
            } catch (InstantiationException e) {
                System.out.println(e);
            }
        }
    
        public static void main(String[] args) {
            new MyTomcat(8080).start();
        }
    }