拦截器:就是在訪问action之前。对其进行拦截!能够在拦截器中做一些逻辑的处理!
比方权限验证。没有权限就不给予訪问!
拦截器等效于servlet中的过滤器!
使用拦截器步骤:
1.定义自己的拦截器:
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.interceptor.Interceptor;
/**
* 定义自己的拦截器,须要实现Intercept接口!
*
*/
public class MyInterceptor implements Interceptor{
public void destroy()
{
}
public void init()
{
}
/**
* 重写intercept方法,在该方法中实现自己的拦截逻辑!
* 调用invocation.invoke()方法放行action!
*/
public String
intercept(ActionInvocation invocation) throws Exception
{
System. out.println("图片上传" );
return invocation.invoke();
// return null;//不运行action
}
}
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2.在struts-interceptor.xml的配置文件里声明:
须要在struts.xml中包括上述配置文件!
struts-interceptor.xml:
<?xml version= "1.0" encoding ="UTF-8" ?>
<!DOCTYPE struts PUBLIC
"-//Apache
Software Foundation//DTD Struts Configuration 2.0//EN"
"http://struts.apache.org/dtds/struts-2.0.dtd">
<struts>
<package name="interceptor" namespace="/" extends="struts-default" >
<!-- 声明拦截器,拦截器声明应该位于action之前-->
<interceptors>
<!--声明自定义的拦截器
-->
<interceptor name= "imageInterceptor"
class= "cn.itheima03.struts2.interceptor.MyInterceptor" ></interceptor>
<!-- 声明拦截器栈
-->
<interceptor-stack name= "myInterceptor">
<interceptor-ref name="imageInterceptor" ></interceptor-ref>
<interceptor-ref name="defaultStack" ></interceptor-ref>
</interceptor-stack>
</interceptors>
<!-- 改动默认的拦截器栈
-->
<default-interceptor-ref name="myInterceptor" ></default-interceptor-ref>
<!--声明action,在运行action之前。会先运行拦截器中的方法
-->
<action name= "interceptorAction_*" method ="{1}"
class= "cn.itheima03.struts2.interceptor.InterceptorTestAction" >
<result>
index.jsp
</result>
</action>
</package >
</struts>
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3.定义action:
import com.opensymphony.xwork2.ActionSupport;
public class InterceptorTestAction extends ActionSupport{
public String
interceptor(){
System. out.println("interceptor" );
return SUCCESS ;
}
}
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