SpringBoot登录拦截器配置

1，拦截器

public class LoginInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        // 检查登录逻辑
        HttpSession session = request.getSession();
        Object loginUser = session.getAttribute("loginUser");  // 通过session属性的loginUser进行判断是否登录
        if (loginUser != null){
            return true;
        }else {
            request.setAttribute("msg","请登陆后访问");
            // response.sendRedirect("/login"); 
            request.getRequestDispatcher("/login").forward(request,response); // 使用重定向携带req res进行跳转
            return false;
        }
    }
}

2，注册拦截器

// 将类表示为配置类
@Configuration
// 开启mvc的注解驱动
@EnableWebMvc
public class WebConfig implements WebMvcConfigurer {
    // 拦截器  拦截所有路径，放行静态资源与登录页，错误页
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        LoginInterceptor loginInterceptor = new LoginInterceptor();
        InterceptorRegistration ir = registry.addInterceptor(loginInterceptor);
        ir.addPathPatterns("/**");  
        ir.excludePathPatterns("/login","/js/**","/css/**","/images/**","/fonts/**","/html/**","/error");
    }
}

3，Controller中配置访问登录页的路径及方法

/**
   * 来登录页
   * @return login
   */
  @GetMapping(value = {"/login","/"})
  public String loginPage(HttpSession session){
      // 再次访问login页面即视为退出登录
      session.setAttribute("loginUser",null);
      return "login";
  }

4，若此时配置完成后，登录拦截器生效，但放行的静态资源仍无法访问到，在WebConfig中配置

private static final String[] CLASSPATH_RESOURCE_LOCATIONS = {
        "classpath:/META-INF/resources/", "classpath:/resources/",
        "classpath:/static/", "classpath:/public/" };
@Override
public void addResourceHandlers(ResourceHandlerRegistry registry) {
    if (!registry.hasMappingForPattern("/webjars/**")) {
        registry.addResourceHandler("/webjars/**").addResourceLocations(
                "classpath:/META-INF/resources/webjars/");
    }
    if (!registry.hasMappingForPattern("/**")) {
        registry.addResourceHandler("/**").addResourceLocations(
                CLASSPATH_RESOURCE_LOCATIONS);
    }
}

完整的拦截器注册配置文件

// 将类表示为配置类
@Configuration
// 开启mvc的注解驱动
@EnableWebMvc
public class WebConfig implements WebMvcConfigurer {

    // 拦截器
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        LoginInterceptor loginInterceptor = new LoginInterceptor();
        InterceptorRegistration ir = registry.addInterceptor(loginInterceptor);
        ir.addPathPatterns("/**");
        ir.excludePathPatterns("/login","/js/**","/css/**","/images/**","/fonts/**","/html/**","/error");
    }

    // 异常解析器
    @Override
    public void configureHandlerExceptionResolvers(List<HandlerExceptionResolver> resolvers) {
        SimpleMappingExceptionResolver exceptionResolver = new SimpleMappingExceptionResolver();
        Properties prop = new Properties();
        prop.setProperty("java.lang.ArithmeticException", "error");
        exceptionResolver.setExceptionAttribute("ex");
        resolvers.add(exceptionResolver);
    }

    private static final String[] CLASSPATH_RESOURCE_LOCATIONS = {
            "classpath:/META-INF/resources/", "classpath:/resources/",
            "classpath:/static/", "classpath:/public/" };
    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        if (!registry.hasMappingForPattern("/webjars/**")) {
            registry.addResourceHandler("/webjars/**").addResourceLocations(
                    "classpath:/META-INF/resources/webjars/");
        }
        if (!registry.hasMappingForPattern("/**")) {
            registry.addResourceHandler("/**").addResourceLocations(
                    CLASSPATH_RESOURCE_LOCATIONS);
        }
    }
    
}