springmvc的攔截器和過濾器的區(qū)別

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;
import java.util.Date;

// 注解方式配置過濾器：攔截所有請求（/*）
@WebFilter(urlPatterns = "/*", filterName = "logFilter")
public class LogFilter implements Filter {

    // 過濾器初始化（容器啟動時執(zhí)行）
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        System.out.println("LogFilter初始化...");
    }

    // 核心過濾邏輯
    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) 
            throws IOException, ServletException {
        // 1. 預處理：記錄請求開始時間、URL、方法
        HttpServletRequest httpRequest = (HttpServletRequest) request;
        String url = httpRequest.getRequestURL().toString();
        String method = httpRequest.getMethod();
        long startTime = new Date().getTime();
        System.out.println("====== 請求開始：" + method + " " + url + " ======");

        // 2. 放行請求（繼續(xù)執(zhí)行后續(xù)過濾器或Servlet）
        chain.doFilter(request, response); // 必須調用，否則請求會被攔截

        // 3. 后處理：記錄請求結束時間和耗時
        long endTime = new Date().getTime();
        System.out.println("====== 請求結束：耗時 " + (endTime - startTime) + "ms ======\n");
    }

    // 過濾器銷毀（容器關閉時執(zhí)行）
    @Override
    public void destroy() {
        System.out.println("LogFilter銷毀...");
    }
}

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.ServletComponentScan;

@SpringBootApplication
@ServletComponentScan // 掃描Servlet組件（Filter、Servlet、Listener）
public class DemoApplication {
    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
}

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public class LoginInterceptor implements HandlerInterceptor {

    // Controller方法執(zhí)行前調用（核心攔截邏輯）
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) 
            throws Exception {
        // 1. 獲取Session
        HttpSession session = request.getSession();
        Object user = session.getAttribute("loginUser"); // 假設登錄后用戶信息存于Session的"loginUser"鍵

        // 2. 驗證登錄狀態(tài)
        if (user == null) {
            // 未登錄：重定向到登錄頁
            response.sendRedirect(request.getContextPath() + "/login");
            return false; // 中斷請求，不再執(zhí)行后續(xù)Controller
        } else {
            // 已登錄：放行
            return true; // 繼續(xù)執(zhí)行Controller方法
        }
    }

    // Controller方法執(zhí)行后、視圖渲染前調用
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, 
                           ModelAndView modelAndView) throws Exception {
        // 可在這里修改ModelAndView（如添加公共數據）
        if (modelAndView != null) {
            modelAndView.addObject("currentTime", System.currentTimeMillis());
        }
    }

    // 視圖渲染完成后調用（通常用于資源清理）
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, 
                                Exception ex) throws Exception {
        // 例如：記錄異常日志
        if (ex != null) {
            System.out.println("請求處理異常：" + ex.getMessage());
        }
    }
}

import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

@Configuration // 標識為配置類
public class WebMvcConfig implements WebMvcConfigurer {

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        // 注冊登錄攔截器
        registry.addInterceptor(new LoginInterceptor())
                .addPathPatterns("/**") // 攔截所有路徑
                .excludePathPatterns( // 排除不需要攔截的路徑（登錄頁、靜態(tài)資源等）
                        "/login", 
                        "/doLogin", // 登錄提交接口
                        "/css/**", 
                        "/js/**", 
                        "/images/**"
                );
    }
}