SpringMVC—拦截器

1. 定义拦截器

public class MyInter implements HandlerInterceptor{
	 //主要逻辑：在handler之前执⾏：抽取handler中的冗余代码
	 @Override
	 public boolean preHandle(HttpServletRequest request,
		 HttpServletResponse response, Object handler) throws Exception {
		 System.out.println("pre~~~");
		 HttpSession session = request.getSession();
		 if(session.getAttribute("state")!=null){
			 return true;//放⾏
		 }
		 response.sendRedirect("/longin.jsp");//响应
		 return false;//中断请求
	 }
	 //在handler之后执⾏:进⼀步的响应定制
	 @Override
	 public void postHandle(HttpServletRequest request,
		 HttpServletResponse response, Object handler,
		 ModelAndView modelAndView) throws Exception {
		 System.out.println("post~~");
	 }
	 //在⻚⾯渲染完毕之后，执⾏：资源回收
	 @Override
	 public void afterCompletion(HttpServletRequest request,
		 HttpServletResponse response, Object handler, Exception ex)
		 throws Exception {
		 System.out.println("after");
	 }
 }

2. 定义Controller

@Controller
@RequestMapping("/inter")
@SessionAttributes("state")
public class InterController{
	@RequestMapping("/login")
	public String login(Model model){
		model.addAttribute("state","ok");
		return "index";
	}
	@RequestMapping("/test1")
	public String login(Model model){
		return "index";
	}
	@RequestMapping("/test2")
	public String login(Model model){
		return "index";
	}
}

3. 配置拦截器

<mvc:interceptors>
	<mvc:interceptor>
		 <mvc:mapping path="/inter/test1"/>
		 <mvc:mapping path="/inter/test2"/>
		<!-- <mvc:mapping path="/inter/test*"/> -->  <!--/inter/testaa /inter/test22 /inter/testssssss  -->
		<!-- <mvc:mapping path="/inter/**"/> -->  <!-- /inter/a/b/c/d /inter/cc/ss/dfd  -->
		<!-- <mvc:exclude-mapping path="/inter/login"/> -->  <!-- 不拦截此路径 -->
		 <bean class="com.baizhi.interceptor.MyInter1"></bean>  <!-- 拦截器类 -->
 	</mvc:interceptor>
</mvc:interceptors>

当没登录的情况下***state***是null，这是访问/test1和/test2会被拦截到登录页面；