Java Web检查用户登录状态(防止用户访问到非法页面)

package com.nowcoder.community.annotation;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface LoginRequired {
}

@LoginRequired
@RequestMapping(path = "/setting",method = RequestMethod.GET)
public String getSettingPage(){
    return "/site/setting";
}

package com.nowcoder.community.controller.Interceptor;
import com.nowcoder.community.annotation.LoginRequired;
import com.nowcoder.community.entity.User;
import com.nowcoder.community.util.HostHolder;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.lang.reflect.Method;
@Component
public class LoginRequireInterception implements HandlerInterceptor {
    @Autowired
    private HostHolder hostHolder;
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        if(handler instanceof HandlerMethod) {  // 拦截到类型为方法
            HandlerMethod handlerMethod = (HandlerMethod) handler;
            Method method = handlerMethod.getMethod();  // 获取方法
            LoginRequired loginRequired = method.getAnnotation(LoginRequired.class);  // 获取方法的注解
            if (loginRequired != null && hostHolder.getUser() == null) {  // 方法是loginRequired且user没登陆，需要拦截
                response.sendRedirect(request.getContextPath() + "/login");
                return false;
            }
        }
        return true;
    }
}

package com.nowcoder.community.config;
import com.nowcoder.community.controller.Interceptor.AlphaInterceptor;
import com.nowcoder.community.controller.Interceptor.LoginRequireInterception;
import com.nowcoder.community.controller.Interceptor.LoginTicketInterceptor;
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 WebMvcConfig implements WebMvcConfigurer {
    @Autowired
    private AlphaInterceptor alphaInterceptor;
    @Autowired
    private LoginTicketInterceptor loginTicketInterceptor;
    @Autowired
    private LoginRequireInterception loginRequireInterception;
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        // 通过重写addInterceptors()方法，可以配置拦截器，对请求进行预处理或后处理。
        registry.addInterceptor(loginRequireInterception)
                .excludePathPatterns("/**/*.css", "/**/*.js", "/**/*.png", "/**/*.jpg", "/**/*.jpeg");
    }
}