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SpringMVC拦截器

2019-09-10 19:00:53 作者：互联网

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

HelloController

@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：

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

标签：Exception,拦截器,preHandle,SpringMVC,System,public,afterCompletion
来源： https://blog.csdn.net/Luck_ZZ/article/details/100676753