【仿写tomcat】五、响应静态资源（访问html页面）、路由支持以及多线程改进

访问html页面

如果我们想访问html页面其实就是将本地的html文件以流的方式响应给前端即可，下面我们对HttpResponseServlet这个类做一些改造

package com.tomcatServer.domain;import com.tomcatServer.utils.ScanUtil;import java.io.IOException;
import java.io.PrintWriter;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;/*** http servlet响应** @author ez4sterben* @date 2023/08/15*/
public class HttpServletResponse {private final PrintWriter out;private static final String response;private static final String htmlResponse;public HttpServletResponse(PrintWriter out) {this.out = out;}static {response = "HTTP/1.1 200 OK\r\n" +"Content-Type: text/plain\r\n" +"\r\n";htmlResponse = "HTTP/1.1 200 OK\r\n" +"Content-Type: text/html\r\n" +"\r\n";}/*** 写** @param content 内容*/public void write(String content) {out.println(response + content);}/*** 编写html** @param htmlFileName html文件名字* @throws IOException ioexception*/public void writeHtml(String htmlFileName) throws IOException {Path path = Paths.get(ScanUtil.WEB_APP_PATH + "\\" + htmlFileName);byte[] bytes = Files.readAllBytes(path);out.println(htmlResponse + new String(bytes, StandardCharsets.UTF_8));}
}

writeHtml这个方法将会读取webApp下面的html文件，注意只读取下面一级文件中的html文件，然后将这个文件以二进制流的形式转换成字符串拼接到上面定义的html格式的响应头。

处理静态资源请求

当我们有了解析html文件的方法后，下面要做的就是处理静态资源，也就是判断一下请求路径中是否有.html这个字符串，有的话就把这次请求当做静态资源请求处理，没有的话再交给GET或者POST请求。这个逻辑将添加在SocketStore中，下面展示更改玩的SocketStore代码

package com.tomcatServer.socket;import com.tomcatServer.domain.HttpServletRequest;
import com.tomcatServer.domain.HttpServletResponse;
import com.tomcatServer.utils.ScanUtil;
import com.tomcatServer.utils.ServletUtil;import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Map;/*** 套接字存储** @author ez4sterben* @date 2023/08/15*/
public class SocketStore {private static ServerSocket socket;public static void connect(Integer port) throws IOException {socket = new ServerSocket(port);}public static void close() throws IOException {socket.close();}public static ServerSocket getSocket() {return socket;}/*** 处理请求** @throws IOException ioexception*/public static void handleRequest(Socket accept) throws IOException {// 获取输入输出流BufferedReader in = new BufferedReader(new InputStreamReader(accept.getInputStream()));PrintWriter out = new PrintWriter(accept.getOutputStream(), true);// 定义字符串接收Http协议内容String inputLine;StringBuilder requestData = new StringBuilder();// 读取数据while ((inputLine = in.readLine()) != null && !inputLine.isEmpty()) {requestData.append(inputLine).append("\r\n");}// 解析request paramString url = requestData.toString().split(" ")[1];// 处理静态资源if(url.contains(".html")){String staticSourceName = (url.split(".html")[0] + ".html").substring(1);HttpServletResponse response = new HttpServletResponse(out);response.writeHtml(staticSourceName);}else {// 处理GET与POST请求if (!requestData.toString().trim().equals("")){handleGetAndPostReuqest(in, out, String.valueOf(requestData));}}// 关闭资源accept.close();}/*** 处理post请求** @param in          在* @param requestData 请求数据* @throws IOException ioexception*/private static void handleGetAndPostReuqest(BufferedReader in,PrintWriter out, String requestData) throws IOException {// 解析request paramString url = requestData.split(" ")[1];String[] urlContent = url.split("\\?");String requestPath = urlContent[0];String params = urlContent[1];String[] paramsKeyValue = params.split("=");// 设置请求参数HttpServletRequest request = new HttpServletRequest();Map<String, String> paramsMap = request.getParams();for (int i = 0; i < paramsKeyValue.length; i += 2) {paramsMap.put(paramsKeyValue[i],paramsKeyValue[i+1]);}if (requestData.contains("POST")) {// 解析request bodyint contentLength = Integer.parseInt(requestData.split("Content-Length: ")[1].split("\r\n")[0]);StringBuilder requestBody = new StringBuilder();for (int i = 0; i < contentLength; i++) {requestBody.append((char) in.read());}// 设置request bodyrequest.setRequestBody(String.valueOf(requestBody));// 设置响应内容HttpServletResponse response = new HttpServletResponse(out);ServletUtil.invokePost(requestPath,request,response);}if (requestData.contains("GET")){// 设置响应内容HttpServletResponse response = new HttpServletResponse(out);ServletUtil.invokeGet(requestPath,request,response);}}}

访问测试

接下来我们在index.html里面写点东西并访问一下试试

http://localhost:8080/index.html

路由支持

其实刚才完成这个功能的时候就会发现，如何访问子目录里面的html呢？
这里其实就要写一个小方法来支持路由重定向了，下面编写一个HttpUtil

package com.tomcatServer.utils;import com.tomcatServer.domain.HttpServletRequest;
import com.tomcatServer.domain.HttpServletResponse;import java.io.IOException;public class HttpUtil {private final String redirectPath;public HttpUtil(String redirectPath) {this.redirectPath = redirectPath;}public void forward(HttpServletRequest request, HttpServletResponse response) throws IOException {response.writeHtml(redirectPath);}
}

对HttpServletRequest做一些改进，提供一个加载静态资源的方法。

    public HttpUtil getStaticSource(String path){return new HttpUtil(path);}

其实这样我们的功能就完成了，写一个servlet以及html来测试一下

package tomcatProject.com.ez4sterben.servlet;import com.tomcatServer.annotation.WebServlet;
import com.tomcatServer.domain.HttpServlet;
import com.tomcatServer.domain.HttpServletRequest;
import com.tomcatServer.domain.HttpServletResponse;import java.io.IOException;@WebServlet("/router")
public class RouterServlet extends HttpServlet {@Overridepublic void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {request.getStaticSource("WEB-INF/page/"+request.getParam("path")+".html").forward(request, response);}@Overridepublic void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException {doGet(request, response);}
}

多线程改进

为什么要在这里谈多线程改进呢，其实是因为我们最近本的接收请求，响应请求，响应页面以及完成了，接下来要考虑的就是如何支持并发处理请求，如何配置并发数，如何配置端口等优化问题。

如果想实现并发处理请求的话，实际上只需要预先定义一个线程池即可，把处理请求的方法交给一个任务类并且实现Runnable接口，当然我们后面会再优化这种方案。

package com.tomcatServer.task;import com.tomcatServer.socket.SocketStore;import java.io.IOException;
import java.net.Socket;public class RequestTask implements Runnable{private final Socket accept;public RequestTask(Socket accept) {this.accept = accept;}@Overridepublic void run() {try {SocketStore.handleRequest(accept);} catch (IOException e) {throw new RuntimeException(e);}}
}

        ...public static ExecutorService threadPool;...// 5.初始化线程池threadPool = Executors.newFixedThreadPool(10);// 6.处理http请求try {SocketStore.connect(PORT);while (true){Socket accept = SocketStore.getSocket().accept();if (accept != null){threadPool.submit(new RequestTask(accept));}}} catch (IOException e) {throw new RuntimeException(e);}finally {SocketStore.close();}

【仿写tomcat】六、解析xml文件配置端口、线程池核心参数