拦截器-注解

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()
    {}
}

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>
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

import com.opensymphony.xwork2.ActionInvocation; 
import com.opensymphony.xwork2.interceptor.Interceptor;

@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.