package cn.how2j.javaweb;

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class ParamServlet extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response){
        try {
            String name = request.getParameter("name");
            response.getWriter().println("get name:" + name);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    public void doPost(HttpServletRequest request, HttpServletResponse response){
        try {
            String name = request.getParameter("name");
            response.getWriter().println("post name:" + name);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

}

<?xml version="1.0" encoding="UTF-8"?>
<web-app>
    <servlet>
        <servlet-name>HelloServlet</servlet-name>
        <servlet-class>cn.how2j.javaweb.HelloServlet</servlet-class>
        <init-param>
            <param-name>author</param-name>
            <param-value>how2j(servlet)</param-value>
        </init-param>
        <init-param>
            <param-name>site</param-name>
            <param-value>http://how2j.cn(servlet)</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>HelloServlet</servlet-name>
        <url-pattern>/hello</url-pattern>
    </servlet-mapping>

    <servlet>
        <servlet-name>ParamServlet</servlet-name>
        <servlet-class>cn.how2j.javaweb.ParamServlet</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>ParamServlet</servlet-name>
        <url-pattern>/param</url-pattern>
    </servlet-mapping>

</web-app>

package cn.how2j.diytomcat.http;

import cn.how2j.diytomcat.catalina.Context;
import cn.how2j.diytomcat.catalina.Engine;
import cn.how2j.diytomcat.catalina.Service;
import cn.how2j.diytomcat.util.MiniBrowser;
import cn.hutool.core.convert.Convert;
import cn.hutool.core.convert.Converter;
import cn.hutool.core.util.ArrayUtil;
import cn.hutool.core.util.StrUtil;
import cn.hutool.core.util.URLUtil;

import javax.servlet.ServletContext;
import java.io.IOException;
import java.io.InputStream;
import java.net.Socket;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Map;

public class Request extends BaseRequest{

    private String requestString;
    private String uri;
    private Socket socket;
    private Context context;
    private Service service;
    private String method;
    private String queryString;
    private Map<String, String[]> parameterMap;

    public Request(Socket socket, Service service) throws IOException {
        this.parameterMap = new HashMap();
        this.socket = socket;
        this.service = service;
        parseHttpRequest();
        if(StrUtil.isEmpty(requestString))
            return;
        parseUri();
        parseContext();
        parseMethod();
        if(!"/".equals(context.getPath())){
            uri = StrUtil.removePrefix(uri, context.getPath());
            if(StrUtil.isEmpty(uri))
                uri = "/";
        }

        parseParameters();

    }

    private void parseMethod() {
        method = StrUtil.subBefore(requestString, " ", false);
    }

    private void parseContext() {
        Engine engine = service.getEngine();
        context = engine.getDefaultHost().getContext(uri);
        if(null!=context)
            return;
        String path = StrUtil.subBetween(uri, "/", "/");
        if (null == path)
            path = "/";
        else
            path = "/" + path;
        context = engine.getDefaultHost().getContext(path);
        if (null == context)
            context = engine.getDefaultHost().getContext("/");
    }

    private void parseHttpRequest() throws IOException {
        InputStream is = this.socket.getInputStream();
        byte[] bytes = MiniBrowser.readBytes(is,false);
        requestString = new String(bytes, "utf-8");
    }

    private void parseUri() {
        String temp;

        temp = StrUtil.subBetween(requestString, " ", " ");
        if (!StrUtil.contains(temp, '?')) {
            uri = temp;
            return;
        }
        temp = StrUtil.subBefore(temp, '?', false);
        uri = temp;
    }

    public Context getContext() {
        return context;
    }

    public String getUri() {
        return uri;
    }

    public String getRequestString(){
        return requestString;
    }

    @Override
    public String getMethod() {
        return method;
    }

    public ServletContext getServletContext() {
        return context.getServletContext();
    }
    public String getRealPath(String path) {
        return getServletContext().getRealPath(path);
    }
    private void parseParameters() {
        System.out.println(requestString);
        if ("GET".equals(this.getMethod())) {
            String url = StrUtil.subBetween(requestString, " ", " ");
            if (StrUtil.contains(url, '?')) {
                queryString = StrUtil.subAfter(url, '?', false);
            }
        }
        if ("POST".equals(this.getMethod())) {
            queryString = StrUtil.subAfter(requestString, "\r\n\r\n", false);
        }
        if (null == queryString || 0==queryString.length())
            return;
        queryString = URLUtil.decode(queryString);
        String[] parameterValues = queryString.split("&");
        if (null != parameterValues) {
            for (String parameterValue : parameterValues) {
                String[] nameValues = parameterValue.split("=");
                String name = nameValues[0];
                String value = nameValues[1];
                String values[] = parameterMap.get(name);
                if (null == values) {
                    values = new String[] { value };
                    parameterMap.put(name, values);
                } else {
                    values = ArrayUtil.append(values, value);
                    parameterMap.put(name, values);
                }
            }
        }
    }

    public String getParameter(String name) {
        String values[] = parameterMap.get(name);
        if (null != values && 0 != values.length)
            return values[0];
        return null;
    }

    public Map getParameterMap() {
        return parameterMap;
    }

    public Enumeration getParameterNames() {
        return Collections.enumeration(parameterMap.keySet());
    }

    public String[] getParameterValues(String name) {
        return parameterMap.get(name);
    }
}

package cn.how2j.diytomcat.util;

import java.io.*;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.net.URL;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;

import cn.hutool.core.convert.Convert;
import cn.hutool.core.util.ZipUtil;
import cn.hutool.http.HttpUtil;

public class MiniBrowser {

    public static void main(String[] args) throws Exception {
        String url = "http://static.how2j.cn/diytomcat.html";
        String contentString= getContentString(url,false);
        System.out.println(contentString);
        String httpString= getHttpString(url,false);
        System.out.println(httpString);
    }

    public static byte[] getContentBytes(String url, Map<String,Object> params, boolean isGet) {
        return getContentBytes(url, false,params,isGet);
    }

    public static byte[] getContentBytes(String url, boolean gzip) {
        return getContentBytes(url, gzip,null,true);
    }

    public static byte[] getContentBytes(String url) {
        return getContentBytes(url, false,null,true);
    }

    public static String getContentString(String url, Map<String,Object> params, boolean isGet) {
        return getContentString(url,false,params,isGet);
    }

    public static String getContentString(String url, boolean gzip) {
        return getContentString(url, gzip, null, true);
    }

    public static String getContentString(String url) {
        return getContentString(url, false, null, true);
    }

    public static String getContentString(String url, boolean gzip, Map<String,Object> params, boolean isGet) {
        byte[] result = getContentBytes(url, gzip,params,isGet);
        if(null==result)
            return null;
        try {
            return new String(result,"utf-8").trim();
        } catch (UnsupportedEncodingException e) {
            return null;
        }
    }

    public static byte[] getContentBytes(String url, boolean gzip, Map<String,Object> params, boolean isGet) {
        byte[] response = getHttpBytes(url,gzip,params,isGet);
        byte[] doubleReturn = "\r\n\r\n".getBytes();

        int pos = -1;
        for (int i = 0; i < response.length-doubleReturn.length; i++) {
            byte[] temp = Arrays.copyOfRange(response, i, i + doubleReturn.length);

            if(Arrays.equals(temp, doubleReturn)) {
                pos = i;
                break;
            }
        }
        if(-1==pos)
            return null;

        pos += doubleReturn.length;

        byte[] result = Arrays.copyOfRange(response, pos, response.length);
        return result;
    }

    public static String getHttpString(String url,boolean gzip) {
        return getHttpString(url, gzip, null, true);
    }

    public static String getHttpString(String url) {
        return getHttpString(url, false, null, true);
    }

    public static String getHttpString(String url,boolean gzip, Map<String,Object> params, boolean isGet) {
        byte[]  bytes=getHttpBytes(url,gzip,params,isGet);
        return new String(bytes).trim();
    }

    public static String getHttpString(String url, Map<String,Object> params, boolean isGet) {
        return getHttpString(url,false,params,isGet);
    }

    public static byte[] getHttpBytes(String url,boolean gzip, Map<String,Object> params, boolean isGet) {
        String method = isGet?"GET":"POST";
        byte[] result = null;
        try {
            URL u = new URL(url);
            Socket client = new Socket();
            int port = u.getPort();
            if(-1==port)
                port = 80;
            InetSocketAddress inetSocketAddress = new InetSocketAddress(u.getHost(), port);
            client.connect(inetSocketAddress, 1000);
            Map<String,String> requestHeaders = new HashMap<>();

            requestHeaders.put("Host", u.getHost()+":"+port);
            requestHeaders.put("Accept", "text/html");
            requestHeaders.put("Connection", "close");
            requestHeaders.put("User-Agent", "how2j mini brower / java1.8");

            if(gzip)
                requestHeaders.put("Accept-Encoding", "gzip");

            String path = u.getPath();
            if(path.length()==0)
                path = "/";

            if(null!=params && isGet){
                String paramsString = HttpUtil.toParams(params);
                path = path + "?" + paramsString;
            }

            String firstLine = method + " " + path + " HTTP/1.1\r\n";

            StringBuffer httpRequestString = new StringBuffer();
            httpRequestString.append(firstLine);
            Set<String> headers = requestHeaders.keySet();
            for (String header : headers) {
                String headerLine = header + ":" + requestHeaders.get(header)+"\r\n";
                httpRequestString.append(headerLine);
            }

            if(null!=params && !isGet){
                String paramsString = HttpUtil.toParams(params);
                httpRequestString.append("\r\n");
                httpRequestString.append(paramsString);
            }

            PrintWriter pWriter = new PrintWriter(client.getOutputStream(), true);
            pWriter.println(httpRequestString);
            InputStream is = client.getInputStream();

            result = readBytes(is,true);
            client.close();
        } catch (Exception e) {
            e.printStackTrace();
            try {
                result = e.toString().getBytes("utf-8");
            } catch (UnsupportedEncodingException e1) {
                e1.printStackTrace();
            }
        }

        return result;

    }

    public static byte[] readBytes(InputStream is, boolean fully) throws IOException {
        int buffer_size = 1024;
        byte buffer[] = new byte[buffer_size];
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        while(true) {
            int length = is.read(buffer);
            if(-1==length)
                break;
            baos.write(buffer, 0, length);
            if(!fully && length!=buffer_size)
                    break;
        }
        byte[] result =baos.toByteArray();
        return result;
    }
}

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 cn.hutool.core.util.ZipUtil;
import cn.hutool.http.HttpUtil;
import org.junit.Assert;
import org.junit.BeforeClass;
import org.junit.Test;
import sun.net.www.content.text.plain;

import java.io.ByteArrayOutputStream;
import java.util.HashMap;
import java.util.Map;
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");
        Assert.assertEquals(html,"Hello DIY Tomcat from index.html@a");
    }

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

    @Test
    public void test404() {
        String response  = getHttpString("/not_exist.html");
        containAssert(response, "HTTP/1.1 404 Not Found");
    }
    @Test
    public void test500() {
        String response  = getHttpString("/500.html");
        containAssert(response, "HTTP/1.1 500 Internal Server Error");
    }

    @Test
    public void testaTxt() {
        String response  = getHttpString("/a.txt");
        containAssert(response, "Content-Type: text/plain");
    }

    @Test
    public void testPNG() {
        byte[] bytes = getContentBytes("/logo.png");
        int pngFileLength = 1672;
        Assert.assertEquals(pngFileLength, bytes.length);
    }
    @Test
    public void testPDF() {
        byte[] bytes = getContentBytes("/etf.pdf");
        int pngFileLength = 3590775;
        Assert.assertEquals(pngFileLength, bytes.length);
    }

    @Test
    public void testhello() {
        String html = getContentString("/j2ee/hello");
        Assert.assertEquals(html,"Hello DIY Tomcat from HelloServlet");
    }

    @Test
    public void testJavawebHello() {
        String html = getContentString("/javaweb/hello");
        containAssert(html,"Hello DIY Tomcat from HelloServlet@javaweb");
    }

    @Test
    public void testJavawebHelloSingleton() {
        String html1 = getContentString("/javaweb/hello");
        String html2 = getContentString("/javaweb/hello");
        Assert.assertEquals(html1,html2);
    }
    @Test
    public void testgetParam() {
        String uri = "/javaweb/param";
        String url = StrUtil.format("http://{}:{}{}", ip,port,uri);
        Map<String,Object> params = new HashMap<>();
        params.put("name","meepo");
        String html = MiniBrowser.getContentString(url, params, true);
        Assert.assertEquals(html,"get name:meepo");
    }
    @Test
    public void testpostParam() {
        String uri = "/javaweb/param";
        String url = StrUtil.format("http://{}:{}{}", ip,port,uri);
        Map<String,Object> params = new HashMap<>();
        params.put("name","meepo");
        String html = MiniBrowser.getContentString(url, params, false);
        Assert.assertEquals(html,"post name:meepo");

    }
    private byte[] getContentBytes(String uri) {
        return getContentBytes(uri,false);
    }
    private byte[] getContentBytes(String uri,boolean gzip) {
        String url = StrUtil.format("http://{}:{}{}", ip,port,uri);
        return MiniBrowser.getContentBytes(url,false);
    }
    private String getContentString(String uri) {
        String url = StrUtil.format("http://{}:{}{}", ip,port,uri);
        String content = MiniBrowser.getContentString(url);
        return content;
    }
    private String getHttpString(String uri) {
        String url = StrUtil.format("http://{}:{}{}", ip,port,uri);
        String http = MiniBrowser.getHttpString(url);
        return http;
    }
    private void containAssert(String html, String string) {
        boolean match = StrUtil.containsAny(html, string);
        Assert.assertTrue(match);
    }
}