第三方集成时通过.j登录后直接调整到x5首页，在登录前先判断用户是否已登录，如果登录过强制注销

import java.io.IOException;
import java.sql.Date;
import java.util.ArrayList;
 
import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.dom4j.Document;
 
import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;
import com.justep.biz.client.ActionEngine;
import com.justep.biz.client.ActionResult;
import com.justep.biz.client.ActionUtils;
import com.justep.ui.JustepConfig;
import com.justep.ui.util.NetUtils;
 
 
public class Login extends com.justep.ui.impl.JProcessorImpl  {
    public void execute(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {   
       
    	String username = request.getParameter("username");
    	
    	//判断用户是否登录，如果登录强制注销
		ActionResult onLineResult = ActionEngine.invokeActions(JustepConfig.getBusinessServer() + "/onlineUsers", null, null, null, "application/json", "application/json", null, null, "get", null);
		JSONObject onLineContent = (JSONObject) onLineResult.getContent();
		JSONObject data = (JSONObject) ((JSONObject)onLineContent.get("data")).get("value");
		JSONArray ar = (JSONArray) data.get("rows");
		for (int i = 0; i < ar.size(); i++) {//解析在线用户数据的JSONArray
			  JSONObject jsonObject = ar.getJSONObject(i);
			  String name = (String) ((JSONObject)jsonObject.get("name")).get("value");
			  String bsessionID = (String) ((JSONObject)jsonObject.get("sessionid")).get("value");
			  if(name.equals(username)){
				ActionEngine.logout(bsessionID, ActionUtils.JSON_CONTENT_TYPE);  	//注销已登录的当前用户			  
			}
			 
		}

		//用户登录
        JSONObject content = null;
        String bsessionid = "";
        //从cookie中获取已有的bsessionid
        Cookie[] cookies = request.getCookies();
        if (cookies != null){
            for (int i = 0; i < cookies.length; i++) {
              String name = cookies[i].getName();
              if(name.equals("bsessionid")){
                  bsessionid = cookies[i].getValue();
              }
            }
        }
        //判断bsessionid是否超时
        ActionResult checkResult = ActionEngine.checkSession(bsessionid, ActionUtils.JSON_CONTENT_TYPE);
        if (checkResult.isSessionTimeOut()) {
            String password = request.getParameter("password");                   
            String ip = request.getRemoteAddr();
            String language = "zh_CN";
            Date loginDate = new Date(System.currentTimeMillis());
            ActionResult actionResult = ActionEngine.login2(username, password, ip, language, loginDate, null, ActionUtils.JSON_CONTENT_TYPE, null);
            content = (JSONObject) actionResult.getContent();
            bsessionid = actionResult.getBSessionID();
            //把bsessionid放到Cookie中
            Cookie cookie = new Cookie("bsessionid",bsessionid);
            cookie.setMaxAge(-1);
            cookie.setPath("/");    
            response.addCookie(cookie);
        } else {
            content = (JSONObject) checkResult.getContent();
        }
        content.put("bsessionid", bsessionid);
        response.setCharacterEncoding("UTF-8");
        response.addHeader("Access-Control-Allow-Origin", "*");
        response.setContentType(ActionUtils.JSON_CONTENT_TYPE);
        response.sendRedirect("/x5/UI2/portal/pc3/index.w");  
        response.flushBuffer();
         
    }
}