* Application * @SpringBootApplication(scanBasePackages = {"com.base"}) scanBasePackages 扫描基础类包 * @ServletComponentScan(basePackages = {"com.base"}) 扫描服务程序组件 （@WebServlet、@WebFilter、@WebListener等注解注解） * 启用@ServletComponentScan 注解后 Servlet、Filter、Listener可以直接通过@WebServlet、@WebFilter、@WebListener注解自动注册，无需其他代码。 * @author 刘志强 * @created Create Time: 2019/5/23 */ @SpringBootApplication(scanBasePackages = {"com.base"}) @ServletComponentScan(basePackages = {"com.base"}) public class Application implements CommandLineRunner { private final Logger logger = LoggerFactory.getLogger(this.getClass()); public static void main(String[] args) { SpringApplication.run(Application.class, args); } @Override public void run(String... strings) throws Exception { logger.info("程序启动"); } } ``` ==用@ServletComponentScan注解后，Servlet、Filter、Listener可以直接通过@WebServlet、@WebFilter、@WebListener注解自动注册，无需其他代码。== ### 拦截器 拦截器应用场景 #### 1. 用拦截器控制单点登录 ##### 前后端不分离，使用session： ###### 登录 登录时将用户信息存储至session中。 session.setAttribute("usserId",user.getId()); 然后在将userId和sessionId 进行绑定存储至redis（也可以使用别的全局唯一数据源来存储，如静态Map,或别的缓存中间件） redisTemplate.opsForValue().set(user.getId(),session.getId()); ##### 拦截器判断是否在别处登录 拦截器从session中取出userId Long userId = (Long)session.getAttribute("usserId"); =》 能取到表示已登录。取不到表示未登录或session过期已下线 然后在根据userId从redis中取出sessionId 根据redis中的sessionId 和当前登录sessionId进行比较 String sessionId = (String) redisTemplate.opsForValue().get(userId); if (sessionId === session.getId()) =》 如果一致表示没有在别处登录，如果不一致表示用户已在别处登录(因为如果有另一人在别处登录相同userId的redis会覆盖掉) #### 前后端分离: ###### 登录 登录时将用户信息存储至redis中。 redisTemplate.opsForValue().set(token,user.getId()); 然后在将userId和token 进行绑定存储至redis（也可以使用别的全局唯一数据源来存储，如静态Map,或别的缓存中间件） redisTemplate.opsForValue().set(user.getId(),token); ##### 拦截器判断是否在别处登录 拦截器从redis中根据token取出userId Long userId = (Long)redisTemplate.opsForValue().get(token); =》 能取到表示已登录。取不到表示未登录或token过期已下线 然后在根据userId从redis中取出token 根据redis中的token 和当前登录token进行比较 String redisToken = (String) redisTemplate.opsForValue().get(userId); if (redisToken === token) =》 如果一致表示没有在别处登录，如果不一致表示用户已在别处登录(因为如果有另一人在别处登录相同userId的redis会覆盖掉) ### Intercept.java ``` package com.base.config.Interceptor; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.stereotype.Component; import org.springframework.web.servlet.HandlerInterceptor; import org.springframework.web.servlet.ModelAndView; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; /** * 拦截器 */ @Component public class Intercept implements HandlerInterceptor { protected Logger logger = LoggerFactory.getLogger(getClass()); @Override public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o) throws Exception { logger.info("Controller方法调用前，被调用"); return true; } @Override public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception { logger.info("请求处理之后进行调用，但是在视图被渲染之前（Controller方法调用之后)"); } @Override public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception { logger.info("在整个请求结束之后被调用，也就是在DispatcherServlet 渲染了对应的视图之后执行（主要是用于进行资源清理工作）"); } } ``` ==@Component 创建实例== ### WebMvcConfig.java 将拦截器实例注册 ``` package com.base.config; import com.base.config.Interceptor.Intercept; import com.base.config.Interceptor.OtherIntercept; 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.ResourceHandlerRegistry; import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter; /** * 开发公司：个人 * 版权：刘志强 *
* WebMvcConfig * * @author 刘志强 * @created Create Time: 2019/2/16 */ @Configuration public class WebMvcConfig extends WebMvcConfigurerAdapter { @Autowired public Intercept intercept; @Autowired public OtherIntercept otherIntercept; //添加资源处理程序，resources资源目录下的static目录下的资源可以被直接访问 @Override public void addResourceHandlers(ResourceHandlerRegistry registry) { registry.addResourceHandler("/static/**").addResourceLocations("classpath:/static/"); } @Override public void addInterceptors(InterceptorRegistry registry) { /** * 多个拦截器组成一个拦截器链 * addPathPatterns 用于添加拦截规则 * excludePathPatterns 用于排除拦截 */ registry.addInterceptor(intercept) .addPathPatterns("/**") .excludePathPatterns("/index"); registry.addInterceptor(otherIntercept) .addPathPatterns("/**"); super.addInterceptors(registry); } } ``` ### 过滤器 #### MainFilter.java ``` package com.base.config.filter; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import javax.servlet.*; import javax.servlet.FilterConfig; import javax.servlet.annotation.WebFilter; import java.io.IOException; /** * 开发公司：个人 * 版权：个人 *
* MainFilter * @WebFilter(filterName = "mainFilter", urlPatterns = {"/*"}) * filterName 过滤器名称 urlPatterns 需要过滤的url * @author 刘志强 * @created Create Time: 2019/5/25 */ @WebFilter(filterName = "mainFilter", urlPatterns = {"/*"}) public class MainFilter implements Filter { protected Logger logger = LoggerFactory.getLogger(getClass()); @Override public void init(FilterConfig filterConfig) throws ServletException { logger.info("过滤器创建"); } @Override public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException { logger.info("执行过滤请求"); filterChain.doFilter(servletRequest, servletResponse); } @Override public void destroy() { logger.info("过滤器销毁"); } } ``` ==init() 服务器启动时执行，初始化过滤器 doFilter() 对urlPatterns声明请求进行过滤时执行== ### 监听器 #### Listener.java ``` package com.base.config.listener; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import javax.servlet.ServletContextEvent; import javax.servlet.ServletContextListener; import javax.servlet.ServletRequestEvent; import javax.servlet.ServletRequestListener; import javax.servlet.annotation.WebListener; import javax.servlet.http.HttpSessionEvent; import javax.servlet.http.HttpSessionListener; /** * 开发公司：个人 * 版权：个人 *
* Listener * * @author 刘志强 * @created Create Time: 2019/5/25 */ @WebListener() public class Listener implements ServletRequestListener, HttpSessionListener,ServletContextListener { protected Logger logger = LoggerFactory.getLogger(getClass()); // ServletRequestListener start @Override public void requestDestroyed(ServletRequestEvent servletRequestEvent) { logger.info("监听器到" + servletRequestEvent.getServletRequest().getServerName() + "被销毁"); } @Override public void requestInitialized(ServletRequestEvent servletRequestEvent) { logger.info("监听器到" + servletRequestEvent.getServletRequest().getServerName() + "被创建"); } // ServletRequestListener end // HttpSessionListener start @Override public void sessionCreated(HttpSessionEvent httpSessionEvent) { logger.info("监听器到" + httpSessionEvent.getSession().getId() + "被创建"); } @Override public void sessionDestroyed(HttpSessionEvent httpSessionEvent) { logger.info("监听器到" + httpSessionEvent.getSession().getId() + "被销毁"); } // HttpSessionListener end // ServletContextListener start @Override public void contextInitialized(ServletContextEvent servletContextEvent) { logger.info("监听器到" + servletContextEvent.getServletContext().getServerInfo() + "被创建"); } @Override public void contextDestroyed(ServletContextEvent servletContextEvent) { logger.info("监听器到" + servletContextEvent.getServletContext().getContextPath() + "被销毁"); } // ServletContextListener end } ```