<?xml version="1.0" encoding="UTF-8"?>
<Server>
    <Context path="/b" docBase="d:/project/diytomcat/b" />
</Server>

Hello DIY Tomcat from index.html@b

package cn.how2j.diytomcat.util;

import cn.hutool.system.SystemUtil;

import java.io.File;

public class Constant {
    public final static String response_head_202 =
            "HTTP/1.1 200 OK\r\n" +
            "Content-Type: {}\r\n\r\n";

    public final static File webappsFolder = new File(SystemUtil.get("user.dir"),"webapps");
    public final static File rootFolder = new File(webappsFolder,"ROOT");

    public static final File confFolder = new File(SystemUtil.get("user.dir"),"conf");
    public static final File serverXmlFile = new File(confFolder, "server.xml");
}

package cn.how2j.diytomcat.util;

import cn.how2j.diytomcat.catalina.Context;
import cn.hutool.core.io.FileUtil;
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;

import java.util.ArrayList;
import java.util.List;

public class ServerXMLUtil {
    public static List<Context> getContexts() {
        List<Context> result = new ArrayList<>();
        String xml = FileUtil.readUtf8String(Constant.serverXmlFile);
        Document d = Jsoup.parse(xml);

        Elements es = d.select("Context");
        for (Element e : es) {
            String path = e.attr("path");
            String docBase = e.attr("docBase");
            Context context = new Context(path, docBase);
            result.add(context);
        }
        return result;
    }
}

package cn.how2j.diytomcat;

import cn.how2j.diytomcat.catalina.Context;
import cn.how2j.diytomcat.http.Request;
import cn.how2j.diytomcat.http.Response;
import cn.how2j.diytomcat.util.Constant;
import cn.how2j.diytomcat.util.ServerXMLUtil;
import cn.how2j.diytomcat.util.ThreadPoolUtil;
import cn.hutool.core.io.FileUtil;
import cn.hutool.core.thread.ThreadUtil;
import cn.hutool.core.util.ArrayUtil;
import cn.hutool.core.util.StrUtil;
import cn.hutool.log.LogFactory;
import cn.hutool.system.SystemUtil;

import java.io.File;
import java.io.IOException;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.*;

public class Bootstrap {
    public static Map<String, Context> contextMap = new HashMap<>();

    public static void main(String[] args) {
        try {
            logJVM();

            scanContextsOnWebAppsFolder();
            scanContextsInServerXML();
            int port = 18080;

            ServerSocket ss = new ServerSocket(port);

            while(true) {
                Socket s =  ss.accept();
                Runnable r = new Runnable(){
                    @Override
                    public void run() {
                        try {
                            Request request = new Request(s);
                            Response response = new Response();
                            String uri = request.getUri();
                            if(null==uri)
                                return;
                            System.out.println("uri:"+uri);

                            Context context = request.getContext();

                            if("/".equals(uri)){
                                String html = "Hello DIY Tomcat from how2j.cn";
                                response.getWriter().println(html);
                            }
                            else{
                                String fileName = StrUtil.removePrefix(uri, "/");
                                File file = FileUtil.file(context.getDocBase(),fileName);
                                if(file.exists()){
                                    String fileContent = FileUtil.readUtf8String(file);
                                    response.getWriter().println(fileContent);

                                    if(fileName.equals("timeConsume.html")){
                                        ThreadUtil.sleep(1000);
                                    }

                                }
                                else{
                                    response.getWriter().println("File Not Found");
                                }
                            }
                            handle200(s, response);
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                };

                ThreadPoolUtil.run(r);

            }
        } catch (IOException e) {
            LogFactory.get().error(e);
            e.printStackTrace();
        }

    }

    private static void scanContextsInServerXML() {
        List<Context> contexts = ServerXMLUtil.getContexts();
        for (Context context : contexts) {
            contextMap.put(context.getPath(), context);
        }
    }

    private static void scanContextsOnWebAppsFolder() {
        File[] folders = Constant.webappsFolder.listFiles();
        for (File folder : folders) {
            if (!folder.isDirectory())
                continue;
            loadContext(folder);
        }
    }

    private static void loadContext(File folder) {
        String path = folder.getName();
        if ("ROOT".equals(path))
            path = "/";
        else
            path = "/" + path;

        String docBase = folder.getAbsolutePath();
        Context context = new Context(path,docBase);

        contextMap.put(context.getPath(), context);
    }

    private static void logJVM() {
        Map<String,String> infos = new LinkedHashMap<>();
        infos.put("Server version", "How2J DiyTomcat/1.0.1");
        infos.put("Server built", "2020-04-08 10:20:22");
        infos.put("Server number", "1.0.1");
        infos.put("OS Name\t", SystemUtil.get("os.name"));
        infos.put("OS Version", SystemUtil.get("os.version"));
        infos.put("Architecture", SystemUtil.get("os.arch"));
        infos.put("Java Home", SystemUtil.get("java.home"));
        infos.put("JVM Version", SystemUtil.get("java.runtime.version"));
        infos.put("JVM Vendor", SystemUtil.get("java.vm.specification.vendor"));

        Set<String> keys = infos.keySet();
        for (String key : keys) {
            LogFactory.get().info(key+":\t\t" + infos.get(key));
        }
    }

    private static void handle200(Socket s, Response response) throws IOException {
        String contentType = response.getContentType();
        String headText = Constant.response_head_202;
        headText = StrUtil.format(headText, contentType);
        byte[] head = headText.getBytes();

        byte[] body = response.getBody();

        byte[] responseBytes = new byte[head.length + body.length];
        ArrayUtil.copy(head, 0, responseBytes, 0, head.length);
        ArrayUtil.copy(body, 0, responseBytes, head.length, body.length);

        OutputStream os = s.getOutputStream();
        os.write(responseBytes);
        s.close();
    }
}

package cn.how2j.diytomcat.test;

import cn.how2j.diytomcat.util.MiniBrowser;
import cn.hutool.core.date.DateUtil;
import cn.hutool.core.date.TimeInterval;
import cn.hutool.core.util.NetUtil;
import cn.hutool.core.util.StrUtil;
import org.junit.Assert;
import org.junit.BeforeClass;
import org.junit.Test;

import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

public class TestTomcat {
    private static int port = 18080;
    private static String ip = "127.0.0.1";
    @BeforeClass
    public static void beforeClass() {
        //所有测试开始前看diy tomcat 是否已经启动了
        if(NetUtil.isUsableLocalPort(port)) {
            System.err.println("请先启动 位于端口: " +port+ " 的diy tomcat，否则无法进行单元测试");
            System.exit(1);
        }
        else {
            System.out.println("检测到 diy tomcat已经启动，开始进行单元测试");
        }
    }

    @Test
    public void testHelloTomcat() {
        String html = getContentString("/");
        Assert.assertEquals(html,"Hello DIY Tomcat from how2j.cn");
    }

    @Test
    public void testTimeConsumeHtml() throws InterruptedException {
        ThreadPoolExecutor threadPool = new ThreadPoolExecutor(20, 20, 60, TimeUnit.SECONDS,
                new LinkedBlockingQueue<Runnable>(10));
            TimeInterval timeInterval = DateUtil.timer();

        for(int i = 0; i<3; i++){
            threadPool.execute(new Runnable(){
                public void run() {
                    getContentString("/timeConsume.html");
                }
            });
        }
        threadPool.shutdown();
        threadPool.awaitTermination(1, TimeUnit.HOURS);

        long duration = timeInterval.intervalMs();

        Assert.assertTrue(duration < 3000);
    }

    @Test
    public void testaIndex() {
        String html = getContentString("/a/index.html");
        Assert.assertEquals(html,"Hello DIY Tomcat from index.html@a");
    }

    @Test
    public void testbIndex() {
        String html = getContentString("/b/index.html");
        Assert.assertEquals(html,"Hello DIY Tomcat from index.html@b");
    }

    private String getContentString(String uri) {
        String url = StrUtil.format("http://{}:{}{}", ip,port,uri);
        String content = MiniBrowser.getContentString(url);
        return content;
    }
}