springmvc之配置拦截器拦截相应的请求

在springmvc.xml文件中配置：

1<mvc:interceptors>
2        <!-- 配置自定义的拦截器 -->
3        <bean class="com.gong.springmvc.interceptors.FirstInterceptor"></bean>
4        <mvc:interceptor>
5            <mvc:mapping path="/emps"/>
6            <bean class="com.gong.springmvc.interceptors.SecondInterceptor"></bean>
7        </mvc:interceptor>
8    </mvc:interceptors>

FirstInterceptor.java

1package com.gong.springmvc.interceptors;
2
3import javax.servlet.http.HttpServletRequest;
4import javax.servlet.http.HttpServletResponse;
5
6import org.springframework.web.servlet.HandlerInterceptor;
7import org.springframework.web.servlet.ModelAndView;
8
9public class FirstInterceptor implements HandlerInterceptor{
10    
11    //该方法在目标方法之前被调用
12    //如果返回true，则继续调用后续的拦截器和目标方法，若为false，则不会在调用后续的拦截器和目标方法
13    //该方法可以考虑做权限、日志、事务等
14    @Override
15    public boolean preHandle(HttpServletRequest request,
16            HttpServletResponse response, Object handler) throws Exception {
17        System.out.println("[FirstInterceptor] preHandle");
18        return true;
19    }
20    
21    //调用目标方法之后，但在渲染视图之前被调用
22    //可以修改请求域中的属性或视图做出修改
23    @Override
24    public void postHandle(HttpServletRequest request,
25            HttpServletResponse response, Object handler,
26            ModelAndView modelAndView) throws Exception {
27        System.out.println("[FirstInterceptor] postHandle");
28    }
29
30    //在渲染视图之后被调用
31    //释放资源
32    @Override
33    public void afterCompletion(HttpServletRequest request,
34            HttpServletResponse response, Object handler, Exception ex)
35            throws Exception {
36        System.out.println("[FirstInterceptor] afterCompletion");
37    }
38
39}

SecondInceptor.java

1package com.gong.springmvc.interceptors;
2
3import javax.servlet.http.HttpServletRequest;
4import javax.servlet.http.HttpServletResponse;
5
6import org.springframework.web.servlet.HandlerInterceptor;
7import org.springframework.web.servlet.ModelAndView;
8
9public class SecondInterceptor implements HandlerInterceptor{
10
11    @Override
12    public boolean preHandle(HttpServletRequest request,
13            HttpServletResponse response, Object handler) throws Exception {
14        System.out.println("[SecondInterceptor] preHandle");
15        return true;
16    }
17
18    @Override
19    public void postHandle(HttpServletRequest request,
20            HttpServletResponse response, Object handler,
21            ModelAndView modelAndView) throws Exception {
22        System.out.println("[SecondInterceptor] postHandle");
23    }
24
25    @Override
26    public void afterCompletion(HttpServletRequest request,
27            HttpServletResponse response, Object handler, Exception ex)
28            throws Exception {
29        System.out.println("[SecondInterceptor] afterCompletion");
30    }
31
32}

在<mvc:mapping path="/emps"/>中可以配置拦截的url地址。

在<mvc:exclude-mapping path=""/>中可以配置不拦截的url地址。

像这种定义在mvc:interceptors下的<bean class="com.gong.springmvc.interceptors.FirstInterceptor"></bean>，没有指定是否拦截，则默认所有请求都调用该拦截器。

在mvc:interceptor下使用<mvc:mapping path="/emps"/>表明要拦截该地址，调用的拦截器是SecondInterceptor。

比如说，我们如果请求地址是/emps，那么两个拦截器都会被调用，在控制台可以看到：

如果请求地址不是/emps，那么只会调用FirstInterceptor拦截器：