import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import java.io.IOException;
// 使用注解注冊過濾器，并指定過濾的 URL 模式
@WebFilter(urlPatterns = "/*")
public class MyFilter implements Filter {
    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        long startTime = System.currentTimeMillis();
        System.out.println("Filter: 請求預(yù)處理 - 設(shè)置字符編碼");
        // 設(shè)置請求和響應(yīng)編碼
        request.setCharacterEncoding("UTF-8");
        response.setCharacterEncoding("UTF-8");
        // 繼續(xù)執(zhí)行過濾器鏈，最終會到達(dá) Servlet
        chain.doFilter(request, response);
        // 響應(yīng)后處理
        long endTime = System.currentTimeMillis();
        System.out.println("Filter: 響應(yīng)后處理 - 請求耗時: " + (endTime - startTime) + "ms");
    }
    // ... 其他 init 和 destroy 方法
}

import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@Component
public class MyInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("Interceptor: preHandle - 在控制器方法執(zhí)行之前");
        // 登錄校驗(yàn)邏輯
        // if (!isLogin(request)) {
        //     response.sendRedirect("/login");
        //     return false; // 中斷執(zhí)行，不會到達(dá) Controller
        // }
        System.out.println("用戶已登錄，放行");
        return true; // 繼續(xù)執(zhí)行，到達(dá) Controller
    }
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("Interceptor: postHandle - 控制器方法執(zhí)行完畢，視圖渲染之前");
    }
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.out.println("Interceptor: afterCompletion - 整個請求已完成，視圖已渲染");
        // 資源清理等工作
    }
}

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
@Configuration
public class WebConfig implements WebMvcConfigurer {
    @Autowired
    private MyInterceptor myInterceptor;
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(myInterceptor)
                .addPathPatterns("/api/**") // 攔截所有 /api 開頭的路徑
                .excludePathPatterns("/api/login"); // 排除登錄接口
    }
}