Struts2 2.18 的 interceptor

首先定义我们自己的Interceptor

 package  com.web.interceptor;

 import  javax.servlet.http.HttpServletRequest;
 import  org.apache.struts2.StrutsStatics;
 import  org.apache.struts2.convention.annotation.ParentPackage;

 import  com.common.utils.StringUtil;
 import  com.opensymphony.xwork2.ActionContext;
 import  com.opensymphony.xwork2.ActionInvocation;
 import  com.opensymphony.xwork2.interceptor.AbstractInterceptor;
 import  com.opensymphony.xwork2.util.ValueStack;
 import  com.web.action.Constants;

 @ParentPackage (value= "struts-default" )
 public   class  LoginInterceptor  extends  AbstractInterceptor
 {
     /**
      *
      */
     private   static   final   long  serialVersionUID = 1L;

     public   static   final  String USER_SESSION_KEY= "wallet.session.user" ;

     public   void  init()
     {}

     @SuppressWarnings ( "unchecked" )
     @Override
     public  String intercept(ActionInvocation invocation)  throws  Exception
     {
         ActionContext actionContext = invocation.getInvocationContext();
         HttpServletRequest request = (HttpServletRequest) actionContext.get(StrutsStatics.HTTP_REQUEST);

         String uri = request.getRequestURI();
         if (uri.indexOf( "index.action" )>- 1 )
         {
             return  Constants.INPUT;
         }
         else   if (uri.indexOf( "login.action" )>- 1 )
         {
             ValueStack vt = actionContext.getValueStack();
             java.util.Map<String, Object> mp = vt.getContext();

             java.util.Map<String, Object> paraMap = (java.util.Map<String,Object>)mp.get(ActionContext.PARAMETERS);
             String[] name = (String[])paraMap.get("user.name" );

             //String name = (String)vt.findValue("user.name");
             if (name!= null  && name.length> 0  && !StringUtil.hasContent(name[ 0 ]))
             {
                 vt.set("fielderror" ,  "必须输入用户名!" );
                 return  Constants.INPUT;
             }
             else   return  invocation.invoke();
         }
         else
             return  invocation.invoke();
     }

     public   void  destroy()
     {}
 }

package com.web.interceptor;

import javax.servlet.http.HttpServletRequest;
import org.apache.struts2.StrutsStatics;
import org.apache.struts2.convention.annotation.ParentPackage;

import com.common.utils.StringUtil;
import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.interceptor.AbstractInterceptor;
import com.opensymphony.xwork2.util.ValueStack;
import com.web.action.Constants;

@ParentPackage(value="struts-default")
public class LoginInterceptor extends AbstractInterceptor
{
	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;

	public static final String USER_SESSION_KEY="wallet.session.user";
	
	public void init()
	{}
	
	@SuppressWarnings("unchecked")
	@Override
	public String intercept(ActionInvocation invocation) throws Exception
	{ 
		ActionContext actionContext = invocation.getInvocationContext();
		HttpServletRequest request = (HttpServletRequest) actionContext.get(StrutsStatics.HTTP_REQUEST);

		String uri = request.getRequestURI();
		if(uri.indexOf("index.action")>-1)
		{
			return Constants.INPUT; 
		}
		else if(uri.indexOf("login.action")>-1)
		{
			ValueStack vt = actionContext.getValueStack();
			java.util.Map<String, Object> mp = vt.getContext();
			
			java.util.Map<String, Object> paraMap = (java.util.Map<String,Object>)mp.get(ActionContext.PARAMETERS);
			String[] name = (String[])paraMap.get("user.name");
		 
			//String name = (String)vt.findValue("user.name");
			if(name!=null && name.length>0 && !StringUtil.hasContent(name[0]))
			{
				vt.set("fielderror", "必须输入用户名!");
				return Constants.INPUT;
			}
			else return invocation.invoke();
		}
		else
			return invocation.invoke();
	}

	public void destroy()
	{}
}

将其注册到struts中，修改struts2.xml文件增加如下内容：

 < package  name= "struts-interceptor"   extends = "struts-default" >
         <interceptors>
             <interceptor name="loginInterceptor"   class = "com.web.interceptor.LoginInterceptor" />
         </interceptors>
     </package >

<package name="struts-interceptor" extends="struts-default"> 
		<interceptors> 
		    <interceptor name="loginInterceptor" class="com.web.interceptor.LoginInterceptor"/>
		</interceptors> 
	</package> 

这样我们自己定义的Interceptor已经设置完成，如果想使用则可以用annotation指定。如

 @InterceptorRefs ({
   @InterceptorRef ( "loginInterceptor" ),
   @InterceptorRef ( "defaultStack" )
 })
 @ParentPackage (value= "struts-interceptor" )
 @Namespace (value= "/application" )
 @Result (name= "input" ,location= "/application/login.jsp" )
 public   class  LoginAction  extends  BaseAction
 {
     private   static   final   long  serialVersionUID = 1L;
 }

@InterceptorRefs({
  @InterceptorRef("loginInterceptor"),
  @InterceptorRef("defaultStack")
})
@ParentPackage(value="struts-interceptor")  
@Namespace(value="/application")  
@Result(name="input",location="/application/login.jsp")
public class LoginAction extends BaseAction
{
	private static final long serialVersionUID = 1L;
}	

我们在LoginAction里使用了刚刚自定义的Interceptor。

官网教程提供的解决方案：

引用

If you get errors like "Unable to find interceptor class referenced by ref-name XYZ". This means that the package where Convention is placing your actions, does not extend the package where the interceptor is defined. To fix this problem either 1)Use @ParentPackage annotation(or struts.convention.default.parent.package) passing the name of the package that defines the interceptor, or 2) Create a package in XML that extends the package that defines the interceptor, and use @ParentPackage(or struts.convention.default.parent.package) to point to it.