1.编写配置文件

spring.datasource.username=root
spring.datasource.password=
spring.datasource.url=jdbc:mysql://localhost:3306/t2?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
#整合mybatis
#指明实体类所在的包---可以使用别名
mybatis.type-aliases-package=com.example.demo03mybatis.pojo
#扫描mybatis/mapper/下的所有xml文件
mybatis.mapper-locations=classpath:mybatis/mapper/*.xml
#设置日期格式
spring.mvc.date-format=yyyy-MM-dd
#端口号配置
server.port=8888
#静态资源默认访问前缀
spring.web.resources.static-locations=classpath:/static
#跳转路径后的指定前缀
#spring.thymeleaf.prefix=classpath:/static/
#spring.mvc.static-path-pattern=/**

2.Dao层接口加上注解

//这个注解表示这是一个mybatis的mapper   mapper.xml创建在resource下面
@Mapper
@Repository
public interface userMapper {

}

------------就这么简单

3--------------拦截器

在config包里面创建两个类------

@Configuration
public class AddConfig implements WebMvcConfigurer {
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        //addPathPatterns("/**")表示拦截所有请求-----excludePathPatterns("/login.html","/qq","/static")表示允许哪些请求
        registry.addInterceptor(new Mycofig()).addPathPatterns("/**").excludePathPatterns("/loging","/qq","/static","/layuimini-2","/layui");
    }
}

第2个类

public class Mycofig implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
       //判断用户有没有登录,登录了就获取其用户名
HttpSession session=request.getSession(); User name=(User)session.getAttribute("user"); if(name==null){ request.getRequestDispatcher("/qq").forward(request,response); return false; }else { return true;} } }