自定义拦截器完成页面自动跳转和页面内容动态展示

<project xmlns="http://maven.apache.org/POM/4.0.0"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.itheima</groupId>
    <artifactId>chapter051</artifactId>
    <version>0.0.1-SNAPSHOT</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.3.RELEASE</version>
    </parent>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>11</source>
                    <target>11</target>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

server.port=8082
spring.thymeleaf.cache=false
spring.messages.basename=i18n.login

package com.itheima.config;

import java.util.Calendar;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.lang.Nullable;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

@Component
public class MyInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
            throws Exception {
        // 用户请求/admin开头路径时，判断用户是否登录
        String uri = request.getRequestURI();
        Object loginUser = request.getSession().getAttribute("loginUser");
        if (uri.startsWith("/admin") && null == loginUser) {
            response.sendRedirect("/toLoginPage");
            return false;
        }
        return true;
    }

    //在页面显示当前年份
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
            @Nullable ModelAndView modelAndView) throws Exception {
        request.setAttribute("currentYear", Calendar.getInstance().get(Calendar.YEAR));
    }
    
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse
            response, Object handler, @Nullable Exception ex) throws Exception {
    }
}

package com.itheima.config;

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.ViewControllerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

@Configuration
public class MyMVCconfig implements WebMvcConfigurer {
    @Autowired
    private MyInterceptor myInterceptor;
    
    // 添加视图管理
    @Override
    public void addViewControllers(ViewControllerRegistry registry) {
        // 请求toLoginPage映射路径或者login.html页面都会自动映射到login.html页面
        registry.addViewController("/toLoginPage").setViewName("login");
        registry.addViewController("/login.html").setViewName("login");
    }

    // 添加拦截器管理
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(myInterceptor).addPathPatterns("/**").excludePathPatterns("/login.html");
    }
}

package com.itheima;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}