// 取出系统中已经存在的session
 @InjectState("SessionImplPO")
 // 判断session是否存在
 public abstract SessionImplPO getPrivilegeResult();

 @InjectStateFlag("SessionImplPO")
 public abstract boolean isSessionExists();

还有获取session的  忘记贴上来了

问题似乎已经解决了

function logout(){
 if(confirm("确认关闭系统?")){
 
 window.location.href="/application/logout.svc";
 
 }

}

然后我写了一个logout service

package com.longcredit.KEye.app.business;

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.apache.commons.logging.Log;
import org.apache.tapestry.IRequestCycle;
import org.apache.tapestry.engine.IEngineService;
import org.apache.tapestry.engine.ILink;
import org.apache.tapestry.services.CookieSource;
import org.apache.tapestry.services.LinkFactory;
import org.apache.tapestry.services.ServiceConstants;

public class LogoutService implements IEngineService {

    private Log _log;

  
    private HttpServletRequest _request;

 
    private HttpServletResponse _response;

 
    private LinkFactory _linkFactory;

    private String _servletPath;
   
   
    @SuppressWarnings("unchecked")
    public ILink getLink(boolean post, Object parameter)
    {
        //该服务允许带参数，所以屏蔽以下两句，若不允许带参数取消注释
        // if (parameter != null)
        // throw new IllegalArgumentException(EngineMessages.serviceNoParameter(this));

        Map parameters = new HashMap();
        //key必须为ServiceConstants所指定的key，否则会有异常
        parameters.put(ServiceConstants.SERVICE, getName());
        //其中parameter参数为，@ServiceLink组件的parameters
        parameters.put(ServiceConstants.PARAMETER,parameter);
        return _linkFactory.constructLink(this, post, parameters, true);
    }

   
    public void service(IRequestCycle cycle) throws IOException
    {
        String serviceName = cycle.getParameter(ServiceConstants.SERVICE);
        System.out.println(serviceName);
        HttpSession session = _request.getSession(false);
       
        //注销清除cookie
        CookieSource cookieSource=cycle.getInfrastructure().getCookieSource();
        //获得@ServiceLink组件的parameters
        Object[] obj=_linkFactory.extractListenerParameters(cycle);
        for (Object object : obj) {
            cookieSource.removeCookieValue((String)object);
        }
       
        if (session != null)
        {
            try
            {
                session.invalidate();
            }
            catch (IllegalStateException ex)
            {
                _log.warn("Exception thrown invalidating HttpSession.", ex);

                // Otherwise, ignore it.
            }
        }

        String url = cycle.getAbsoluteURL(_servletPath);

        _response.sendRedirect(url);
    }

    //指定该service的名字
    public String getName()
    {
        return "logout";
    }

    /** @since 4.0 */
    public void setLog(Log log)
    {
        _log = log;
    }

    /** @since 4.0 */
    public void setRequest(HttpServletRequest request)
    {
        _request = request;
    }

    /** @since 4.0 */
    public void setResponse(HttpServletResponse response)
    {
        _response = response;
    }

    /** @since 4.0 */
    public void setLinkFactory(LinkFactory linkFactory)
    {
        _linkFactory = linkFactory;
    }

    /** @since 4.0 */
    public void setServletPath(String servletPath)
    {
        _servletPath = servletPath;
    }
}

但是不是太理解

晕，没有必要这么复杂，以前说了很多次的转换URL的方法，用那些方法构造你需要跳转页面的URL，一般用pageLink的url，然后throw new RedirectException即可。