一、实现接口
接口 HandlerInterceptor 有：
preHandle()：在目标方法运行之前调用；return true放行，return false不放行
postHandle()：在目标方法运行之后调用
afterCompletion()：在请求整个完成之后；来到目标页面之后调用
拦截器 MyFirstInterceptor
public class MyFirstInterceptor implements HandlerInterceptor {
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
System.out.println("MyFirstInterceptor preHandle");
return true;
}
@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
System.out.println("MyFirstInterceptor postHandle");
}
@Override
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
System.out.println("MyFirstInterceptor afterCompletion");
}
}拦截器 MySecondInterceptor
public class MySecondInterceptor implements HandlerInterceptor {
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
System.out.println("MySecondInterceptor preHandle");
return true;
}
@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
System.out.println("MySecondInterceptor postHandle");
}
@Override
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
System.out.println("MySecondInterceptor afterCompletion");
}
}二、配置拦截器
<?xml version="1.0" encoding="utf-8" ?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc.xsd">
<!--扫描所有组件-->
<context:component-scan base-package="com.example"/>
<mvc:default-servlet-handler/>
<mvc:annotation-driven/>
<mvc:interceptors>
<!--配置某个拦截器，默认是拦截所有请求的-->
<bean class="com.example.interceptor.MyFirstInterceptor"/>
<!--配置某个拦截器更详细的信息-->
<mvc:interceptor>
<mvc:mapping path="/handle01"/>
<bean class="com.example.interceptor.MySecondInterceptor"/>
</mvc:interceptor>
</mvc:interceptors>
</beans>三、测试
@Controller
public class HelloController {
@RequestMapping("/handle01")
public String handle01(Map<String, Object> map){
System.out.println("handle01");
return "success.jsp";
}
}success.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" isErrorPage="true" %>
<html>
<head>
<title>Title</title>
</head>
<body>
<%
System.out.println("success.jsp");
%>
<h4>success</h4>
</body>
</html>进行访问：
http://localhost:8080/handle01结果：
MyFirstInterceptor preHandle
MySecondInterceptor preHandle
handle01
MySecondInterceptor postHandle
MyFirstInterceptor postHandle
success.jsp
MySecondInterceptor afterCompletion
MyFirstInterceptor afterCompletion四、拦截流程
1.正常拦截流程：
preHandle、目标方法、postHandle、页面、拦截器afterCompletion
拦截器的preHandle：是按照顺序执行；拦截器的postandle：是按照逆序执行；拦截器的afterCompletion：是按照逆序执行
2.其他拦截流程：
只要preHandler不放行就没有以后的流程；只要放行，afterCompletion都会执行
栗：MyFirstInterceptor放行，MySecondInterceptor不放行
MyFirstInterceptor preHandle
MySecondInterceptor preHandle
MyFirstInterceptor afterCompletion五、WebMvcConfigurer 配置拦截器
@Configuration
public class MyWebMvcConfig implements WebMvcConfigurer {
@Override
public void addInterceptors(InterceptorRegistry registry) {
MyFirstInterceptor first = new MyFirstInterceptor();
MySecondInterceptor second = new MySecondInterceptor();
registry.addInterceptor(first).addPathPatterns("/**");
registry.addInterceptor(second).addPathPatterns("/handle01");
}
}六、springmvc 拦截器与 servlet 过滤器区别
- 过滤器实现 Filter 接口对象，拦截器是实现 HandleInterceptor
- 过滤器是在拦截器之前执行的
- 过滤器是 tomcat 服务器创建的对象，拦截器是 springmvc 容器创建的对象
- 过滤器是一个执行时间点；拦截器是三个执行时间点
- 过滤器可以处理jsp、js、html等；拦截器是侧重拦截Controller的对象，如果你的请求不能被DispatcherServlet接收，这个请求不会执行拦截器的内容
- 拦截器拦截普通类方法执行，过滤器过滤servlet请求响应
