如何在Java中使用自定义请求拦截器 Java处理请求前置过滤逻辑

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

public class MyAuthInterceptor implements HandlerInterceptor {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        // 假设这里做个简单的身份验证
        String token = request.getHeader("X-Auth-Token");
        if (token == null || !token.equals("valid-token-123")) {
            response.setStatus(HttpServletResponse.SC_UNAUTHORIZED); // 401 Unauthorized
            response.getWriter().write("{\"error\": \"Unauthorized\"}");
            response.getWriter().flush();
            return false; // 中断请求
        }
        System.out.println("请求通过认证: " + request.getRequestURI());
        // 可以在这里把用户信息存到request attribute里，方便后续Controller使用
        request.setAttribute("currentUser", "admin");
        return true; // 继续处理请求
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        // 可以在这里记录请求处理时间，或者给视图添加一些公共数据
        if (modelAndView != null) {
            modelAndView.addObject("appName", "MyAwesomeApp");
        }
        System.out.println("Controller执行完毕，准备渲染视图: " + request.getRequestURI());
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        // 请求处理完成，无论成功失败都会执行
        if (ex != null) {
            System.err.println("请求处理异常: " + request.getRequestURI() + ", 异常信息: " + ex.getMessage());
        } else {
            System.out.println("请求处理流程全部结束: " + request.getRequestURI());
        }
        // 资源清理等
    }
}

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 {

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new MyAuthInterceptor())
                .addPathPatterns("/api/**") // 拦截 /api/ 下的所有请求
                .excludePathPatterns("/api/public/**"); // 但排除 /api/public/ 下的请求
        // 你可以注册多个拦截器，它们会按照添加的顺序依次执行preHandle
        // registry.addInterceptor(new AnotherInterceptor()).addPathPatterns("/admin/**");
    }
}