Tomcat原理

Tomcat解析

Tomcat定位为webServer

Tomcat嵌入，servlet

手动实现单机版Tomcat

基本流程图：

首先实现请求对象：

package com.wp;/*
 *@author wupeng
 *@time 2021/6/21-7:58
请求方法
 */

import java.io.IOException;
import java.io.InputStream;

public class MyRequest {
//    请求方法
    private String  requestMethod;
//    请求地址
    private String requestUrl;

    public MyRequest(InputStream inputStream) throws IOException {
        //缓冲区空间
        byte[] buffer = new byte[1024];
        //读取数据的长度
        int len = 0;
        //定义请求变量
        String str = null;

        if((len = inputStream.read(buffer))> 0) {
            str = new String(buffer,0,len);
        }
        //GET /HTTP1.1
        String data = str.split("\n")[0];
        String[] params = data.split(" ");
        this.requestMethod = params[0];
        this.requestUrl = params[1];
    }

    public String getRequestMethod() {
        return requestMethod;
    }

    public void setRequestMethod(String requestMethod) {
        this.requestMethod = requestMethod;
    }

    public String getRequestUrl() {
        return requestUrl;
    }

    public void setRequestUrl(String requestUrl) {
        this.requestUrl = requestUrl;
    }
}

实现响应对象：

package com.wp;/*
 *@author wupeng
 *@time 2021/6/21-8:26

 */

import java.io.IOException;
import java.io.OutputStream;

public class MyResponse {
    private OutputStream outputStream;

    public MyResponse(OutputStream outputStream) {
        this.outputStream = outputStream;
    }
    //将数据写到客户端
    public void write(String str) throws IOException {
        StringBuilder builder = new StringBuilder();
        builder.append("HTTP/1.1 200 OK\n")
                .append("Content-Type:text/html\n")
                .append("\r\n")
                .append("<html>\n")
                .append("<body>")
                .append("<h1>"+str+"</h1>")
                .append("</body>")
                .append("</html>");
        this.outputStream.write(builder.toString().getBytes());
        this.outputStream.flush();
        this.outputStream.close();
    }
}

实现映射关系：

package com.wp;/*
 *@author wupeng
 *@time 2021/6/21-8:35

 */

import java.util.HashMap;

public class MyMapping {
    public static HashMap<String,String> map = new HashMap<>();
    static {
        map.put("/mytomcat","com.wp.MyServlet");
    }

    public HashMap<String,String> getMapping() {
        return map;
    }
}

实现接口：

package com.wp;/*
 *@author wupeng
 *@time 2021/6/21-8:38

 */

import java.io.IOException;

public abstract class MyHttpServlet {
//    定义常量
    public static final String METHOD_GET = "GET";
    public static final String METHOD_POST = "POST";

    //判断什么方法
    public abstract void doGet(MyRequest myRequest,MyResponse myResponse) throws IOException;
    public abstract void doPost(MyRequest myRequest,MyResponse myResponse) throws IOException;

    //根据请求方式来判断调用哪种处理方法
    public void service(MyRequest myRequest,MyResponse myResponse) throws IOException {
        if(METHOD_GET.equals(myRequest.getRequestMethod())) {
            doGet(myRequest,myResponse);
        } else if (METHOD_POST.equals(myRequest.getRequestMethod())){
            doPost(myRequest,myResponse);
        }
    }
}

实现Servlet

package com.wp;/*
 *@author wupeng
 *@time 2021/6/21-8:57
 */

import java.io.IOException;

public class MyServlet extends MyHttpServlet {

    @Override
    public void doGet(MyRequest myRequest, MyResponse myResponse) throws IOException {
        myResponse.write("mytomcat get");
    }

    @Override
    public void doPost(MyRequest myRequest, MyResponse myResponse) throws IOException {
        myResponse.write("post tomcat");
    }
}

实现一个服务：

package com.wp;/*
 *@author wupeng
 *@time 2021/6/21-9:05

 */

import com.sun.corba.se.impl.orbutil.ObjectUtility;
import com.sun.deploy.nativesandbox.comm.Response;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;

public class MyServer  {
    /*
    定义服务端的接受程序，接受Socket请求
     */
    public static void startServer(int port) throws IOException, ClassNotFoundException, IllegalAccessException, InstantiationException {
        //定义服务端套接字
        ServerSocket serverSocket = new ServerSocket(port);
        //定义客户端套接字
        Socket socket = null;
        while(true) {
            socket = serverSocket.accept();
            //获取输入流输出流
            InputStream inputStream = socket.getInputStream();
            OutputStream outputStream = socket.getOutputStream();

            //定义请求对象
            MyRequest request = new MyRequest(inputStream);

            //定义响应对象
            MyResponse response = new MyResponse(outputStream);

            String clazz=  new MyMapping().getMapping().get(request.getRequestUrl());
            if(clazz != null) {
                Class<MyServlet> myServletClass = (Class<MyServlet>) Class.forName(clazz);
                //根据MyservletClass创建对象
                MyServlet myServlet = myServletClass.newInstance();
                myServlet.service(request,response);
            }
        }

    }

    public static void main(String[] args) {
        try {
            startServer(10086);
        }  catch (Exception e) {
            e.printStackTrace();
        }
    }
}
posted @ 2021-06-23 22:11  IT小五  阅读(53)  评论(0)    收藏  举报