手写服务器(2)

Time: 2024-04-25 星期四 19:09:01
Author: Jackasher

手写服务器

这是一个处理静态文件的服务器,服务器可以解析浏览器的地址,并展现相应的页面

package org.example;

import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;

public class Main {
    public static void main(String[] args) throws IOException {
        ServerSocket serverSocket = new ServerSocket(8080);
        System.out.println("Server started on port 8080");

        while (true) {
            Socket socket = serverSocket.accept();
            System.out.println("Connection established");

            BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            PrintWriter writer = new PrintWriter(socket.getOutputStream());

            // 读取HTTP请求的第一行（请求行）
            String requestLine = reader.readLine();
            System.out.println("Received request: " + requestLine);

            // 解析请求URI
            String[] parts = requestLine.split(" ");
            String requestURI = parts[1];

            // 如果请求的是favicon.ico文件，则直接返回空响应
            if (requestURI.equals("/favicon.ico")) {
                writer.write("HTTP/1.1 200 OK\r\n");
                writer.write("\r\n");
                writer.flush();
                writer.close();
                reader.close();
                socket.close();
                System.out.println("Connection closed");
                continue; // 继续监听下一个连接
            }

            // 加载资源文件
            InputStream inputStream = Main.class.getResourceAsStream(requestURI);
            BufferedReader fileReader = new BufferedReader(new InputStreamReader(inputStream));

            // 构建HTTP响应
            writer.write("HTTP/1.1 200 OK\r\n");
            writer.write("Content-Type: text/html\r\n");
            writer.write("\r\n"); // 空行，标志头部结束

            // 将HTML内容写入响应
            String line;
            while ((line = fileReader.readLine()) != null) {
                writer.write(line + "\r\n");
            }

            // 刷新缓冲区，确保数据被发送
            writer.flush();

            // 关闭连接
            writer.close();
            reader.close();
            socket.close();
            System.out.println("Connection closed");
        }
    }
}

接下来完成动态的Servlet,首先我们可以写一个类来解析URL中的请求地址,将其封装在servletMap里面,里面有对应的url和Class

package org.example;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.Node;
import org.dom4j.io.SAXReader;

import java.io.File;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;

public class WebParser {
    public static Map<String, String> parser(String webAppName) throws DocumentException {
        
        //传入项目名称获取地址
        String webPath = webAppName + "/WEB-INF/web.xml";
      
        //根据地址解析web.xml文件
        SAXReader saxReader = new SAXReader();
        org.dom4j.Document document = saxReader.read(WebParser.class.getResourceAsStream(webPath));
        List<Node> nodes = document.selectNodes("/web-app/servlet");
      
        //将Servlet里面的name和Class放入servletInfoMap里面
        Map<String, String> servletInfoMap = new HashMap<String, String>();
        for (Node node : nodes) {
            Element servletElement = (Element) node;
            Element servletNameEle = (Element) servletElement.selectSingleNode("servlet-name");
            String servletName = servletNameEle.getStringValue();
            Element servletClassEle = (Element) servletElement.selectSingleNode("servlet-class");
            String servletClassName = servletClassEle.getStringValue();

            //System.out.println(servletName + " " + servletClassName);

            servletInfoMap.put(servletName, servletClassName);


        }
      
        //将servlet-mapping的name和URL放入servletmappingInfoMap里面
        List<Node> servletMappingNodes = document.selectNodes("/web-app/servlet-mapping");
        Map<String, String> servletMappingInfoMap = new HashMap<String, String>();
        for (Node node : servletMappingNodes) {
            Element element = (Element) node;
            Element element1 = (Element) element.selectSingleNode("url-pattern");
            String urlValue = element1.getStringValue();
            Element element2 = (Element) element.selectSingleNode("servlet-name");
            String servletName = element2.getStringValue();
            servletMappingInfoMap.put(servletName, urlValue);
        }
      
        //最后把URL和Class放在servletMap里面
        Set<String> servletNames = servletInfoMap.keySet();

        Map<String, String> servletMap = new HashMap<String, String>();
        for (String servletName : servletNames) {
            String urlPattern = servletMappingInfoMap.get(servletName);
            String servletClass = servletInfoMap.get(servletName);
            servletMap.put(urlPattern, servletClass);
        }
        System.out.println(servletMap);

        return servletMap;
    }
}