JerrymouseServer

1. 项目简介

2. 环境准备

mvn archetype:generate -DgroupId=com.jerrymouse -DartifactId=jerrymouse-server -DarchetypeArtifactId=maven-archetype-quickstart -DinteractiveMode=false

3. 核心模块设计

jerrymouse-server/
├── src/
│ ├── main/
│ │ ├── java/com/jerrymouse/
│ │ │ ├── core/ # 核心服务器实现
│ │ │ ├── connector/ # 连接器模块
│ │ │ ├── servlet/ # Servlet 容器实现
│ │ │ ├── util/ # 工具类
│ │ │ └── Main.java # 启动类
│ │ └── resources/
│ └── test/ # 测试代码
├── pom.xml
└── webapps/ # Web应用部署目录

<dependencies>
 <!-- Servlet API -->
 <dependency>
 <groupId>jakarta.servlet</groupId>
 <artifactId>jakarta.servlet-api</artifactId>
 <version>6.0.0</version>
 <scope>provided</scope>
 </dependency>
 
 <!-- 其他工具依赖 -->
 <dependency>
 <groupId>org.slf4j</groupId>
 <artifactId>slf4j-api</artifactId>
 <version>2.0.7</version>
 </dependency>
 <dependency>
 <groupId>ch.qos.logback</groupId>
 <artifactId>logback-classic</artifactId>
 <version>1.4.7</version>
 </dependency>
</dependencies>

4. 核心功能实现

// Main.java
public class Main {
 public static void main(String[] args) {
 Server server = new Server();
 server.start();
 }
}

// Server.java
public class Server {
 private Connector connector;
 private ServletContainer servletContainer;
 
 public void start() {
 // 初始化连接器
 connector = new Connector();
 
 // 初始化Servlet容器
 servletContainer = new ServletContainer();
 servletContainer.init();
 
 // 启动连接器
 connector.start();
 
 // 注册关闭钩子
 Runtime.getRuntime().addShutdownHook(new Thread(this::stop));
 }
 
 public void stop() {
 connector.stop();
 servletContainer.destroy();
 }
}

// Connector.java
public class Connector implements Runnable {
 private ServerSocket serverSocket;
 private boolean running;
 private ServletContainer servletContainer;
 
 public void start() {
 try {
 serverSocket = new ServerSocket(8080);
 running = true;
 new Thread(this).start();
 System.out.println("JerrymouseServer started on port 8080");
 } catch (IOException e) {
 throw new RuntimeException("Failed to start server", e);
 }
 }
 
 @Override
 public void run() {
 while (running) {
 try {
 Socket socket = serverSocket.accept();
 new HttpHandler(socket, servletContainer).handle();
 } catch (IOException e) {
 if (running) {
 e.printStackTrace();
 }
 }
 }
 }
 
 public void stop() {
 running = false;
 try {
 serverSocket.close();
 } catch (IOException e) {
 e.printStackTrace();
 }
 }
}

// HttpHandler.java
public class HttpHandler {
 private final Socket socket;
 private final ServletContainer servletContainer;
 
 public HttpHandler(Socket socket, ServletContainer servletContainer) {
 this.socket = socket;
 this.servletContainer = servletContainer;
 }
 
 public void handle() {
 try (InputStream input = socket.getInputStream();
 OutputStream output = socket.getOutputStream()) {
 
 // 解析HTTP请求
 HttpRequest request = parseRequest(input);
 HttpResponse response = new HttpResponse(output);
 
 // 交给Servlet容器处理
 servletContainer.service(request, response);
 
 // 发送响应
 response.flush();
 } catch (IOException e) {
 e.printStackTrace();
 } finally {
 try {
 socket.close();
 } catch (IOException e) {
 e.printStackTrace();
 }
 }
 }
 
 private HttpRequest parseRequest(InputStream input) throws IOException {
 // 实现HTTP请求解析逻辑
 // ...
 }
}

// ServletContainer.java
public class ServletContainer {
 private Map<String, ServletRegistration> servletRegistrations = new HashMap<>();
 private List<FilterRegistration> filterRegistrations = new ArrayList<>();
 private ServletContext servletContext;
 
 public void init() {
 // 初始化ServletContext
 servletContext = new ServletContextImpl();
 
 // 扫描webapps目录下的WEB-INF/web.xml
 loadWebConfig();
 
 // 实例化并初始化所有Servlet和Filter
 initServlets();
 initFilters();
 }
 
 public void service(HttpRequest request, HttpResponse response) {
 // 查找匹配的Servlet
 ServletRegistration registration = findServletRegistration(request.getPath());
 
 if (registration != null) {
 // 创建过滤器链
 FilterChain chain = new ApplicationFilterChain(registration.getServlet());
 
 // 执行过滤器链
 try {
 chain.doFilter(request, response);
 } catch (IOException | ServletException e) {
 // 处理异常
 response.sendError(500, "Internal Server Error");
 }
 } else {
 // 没有找到Servlet,返回404
 response.sendError(404, "Not Found");
 }
 }
 
 // 其他必要方法...
}

5. Servlet 支持实现

// ServletRegistration.java
public class ServletRegistration {
 private String name;
 private String className;
 private String urlPattern;
 private Servlet servlet;
 
 public void load() throws ServletException {
 try {
 Class<?> clazz = Class.forName(className);
 servlet = (Servlet) clazz.getDeclaredConstructor().newInstance();
 servlet.init(new ServletConfigImpl(name, servletContext));
 } catch (Exception e) {
 throw new ServletException("Failed to load servlet: " + className, e);
 }
 }
 
 // Getter和Setter方法...
}

// FilterRegistration.java
public class FilterRegistration {
 private String name;
 private String className;
 private String urlPattern;
 private Filter filter;
 
 public void load() throws ServletException {
 try {
 Class<?> clazz = Class.forName(className);
 filter = (Filter) clazz.getDeclaredConstructor().newInstance();
 filter.init(new FilterConfigImpl(name, servletContext));
 } catch (Exception e) {
 throw new ServletException("Failed to load filter: " + className, e);
 }
 }
 
 // Getter和Setter方法...
}

// ApplicationFilterChain.java
public class ApplicationFilterChain implements FilterChain {
 private final Servlet servlet;
 private final List<Filter> filters;
 private int position = 0;
 
 public ApplicationFilterChain(Servlet servlet, List<Filter> filters) {
 this.servlet = servlet;
 this.filters = filters;
 }
 
 @Override
 public void doFilter(ServletRequest request, ServletResponse response) 
 throws IOException, ServletException {
 if (position < filters.size()) {
 Filter filter = filters.get(position++);
 filter.doFilter(request, response, this);
 } else {
 servlet.service(request, response);
 }
 }
}

6. Session 支持实现

// SessionManager.java
public class SessionManager {
 private Map<String, HttpSession> sessions = new ConcurrentHashMap<>();
 private static final String SESSION_COOKIE_NAME = "JSESSIONID";
 
 public HttpSession getSession(String sessionId, boolean create) {
 if (sessionId != null) {
 HttpSession session = sessions.get(sessionId);
 if (session != null && !session.isExpired()) {
 return session;
 }
 }
 
 if (create) {
 String newSessionId = generateSessionId();
 HttpSession session = new HttpSessionImpl(newSessionId);
 sessions.put(newSessionId, session);
 return session;
 }
 
 return null;
 }
 
 private String generateSessionId() {
 return UUID.randomUUID().toString();
 }
 
 // 其他必要方法...
}

// HttpSessionImpl.java
public class HttpSessionImpl implements HttpSession {
 private final String id;
 private final long creationTime;
 private volatile long lastAccessedTime;
 private int maxInactiveInterval = 1800; // 默认30分钟
 private Map<String, Object> attributes = new ConcurrentHashMap<>();
 
 public HttpSessionImpl(String id) {
 this.id = id;
 this.creationTime = System.currentTimeMillis();
 this.lastAccessedTime = creationTime;
 }
 
 @Override
 public String getId() {
 return id;
 }
 
 @Override
 public long getCreationTime() {
 return creationTime;
 }
 
 @Override
 public long getLastAccessedTime() {
 return lastAccessedTime;
 }
 
 public void access() {
 lastAccessedTime = System.currentTimeMillis();
 }
 
 public boolean isExpired() {
 return System.currentTimeMillis() - lastAccessedTime > maxInactiveInterval * 1000L;
 }
 
 // 其他HttpSession接口方法实现...
}

7. Web应用部署

webapps/
└── myapp/
 ├── WEB-INF/
 │ ├── web.xml
 │ └── classes/
 │ └── com/example/MyServlet.class
 └── index.html

// WebXmlParser.java
public class WebXmlParser {
 public WebAppConfig parse(InputStream input) throws Exception {
 WebAppConfig config = new WebAppConfig();
 
 DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
 DocumentBuilder builder = factory.newDocumentBuilder();
 Document doc = builder.parse(input);
 
 // 解析Servlet配置
 NodeList servletNodes = doc.getElementsByTagName("servlet");
 for (int i = 0; i < servletNodes.getLength(); i++) {
 Element servletElement = (Element) servletNodes.item(i);
 String servletName = getChildText(servletElement, "servlet-name");
 String servletClass = getChildText(servletElement, "servlet-class");
 
 // 解析url-pattern
 String servletPath = null;
 NodeList servletMappingNodes = doc.getElementsByTagName("servlet-mapping");
 for (int j = 0; j < servletMappingNodes.getLength(); j++) {
 Element mappingElement = (Element) servletMappingNodes.item(j);
 String mappingName = getChildText(mappingElement, "servlet-name");
 if (mappingName.equals(servletName)) {
 servletPath = getChildText(mappingElement, "url-pattern");
 break;
 }
 }
 
 if (servletPath != null) {
 config.addServlet(servletName, servletClass, servletPath);
 }
 }
 
 // 解析Filter配置...
 // 解析Listener配置...
 
 return config;
 }
 
 private String getChildText(Element element, String tagName) {
 NodeList nodes = element.getElementsByTagName(tagName);
 if (nodes.getLength() > 0) {
 return nodes.item(0).getTextContent().trim();
 }
 return null;
 }
}

8. 测试与验证

// TestServlet.java
@WebServlet("/test")
public class TestServlet extends HttpServlet {
 @Override
 protected void doGet(HttpServletRequest req, HttpServletResponse resp) 
 throws ServletException, IOException {
 resp.setContentType("text/html");
 PrintWriter out = resp.getWriter();
 out.println("<html><body>");
 out.println("<h1>Hello from JerrymouseServer!</h1>");
 out.println("</body></html>");
 }
}

// LoggingFilter.java
@WebFilter("/*")
public class LoggingFilter implements Filter {
 @Override
 public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
 throws IOException, ServletException {
 System.out.println("Request received: " + ((HttpServletRequest) request).getRequestURI());
 chain.doFilter(request, response);
 System.out.println("Response sent");
 }
 
 // 其他Filter方法...
}

9. 项目构建与运行

mvn clean package

java -cp target/jerrymouse-server-1.0-SNAPSHOT.jar com.jerrymouse.Main

webapps/
└── myapp/
 ├── WEB-INF/
 │ ├── web.xml
 │ └── classes/ (包含编译后的Servlet类)
 └── index.html

10. 扩展与优化建议