//部门与员工的doubleselect
  public Map<Department, List<User>> getDepUser() {
      db=DBConnectionManager.getInstance();
      con=db.getConnection("idb");
      sql="select departmentcode,departmentname from tb_department order by departmentcode";
      //ArrayList listDepUser=new ArrayList();
      Map<Department,List<User>> mapDepUser=new HashMap<Department,List<User>>();
      try {
          ps=con.prepareStatement(sql);
          rs=ps.executeQuery();
          while(rs.next()){
              Department department=new Department();
              department.setDepartmentcode(rs.getString("departmentcode"));
              department.setDepartmentname(rs.getString("departmentname"));
              sql2="select userid,username from tb_user where departmentcode='"+rs.getString("departmentcode")+"'";
              ps=con.prepareStatement(sql2);
              rs1=ps.executeQuery();
              List<User> uList=new ArrayList<User>();
              while(rs1.next()) {
                  //List<User> uList=new ArrayList<User>();
                  User user=new User();
                  user.setUserid(rs1.getString("userid"));
                  user.setUsername(rs1.getString("username"));
                  uList.add(user);
                  //mapDepUser.put(department, uList);
              }
              mapDepUser.put(department, uList);
          }
      }catch(SQLException ex) {
          ex.printStackTrace();
      }finally {
          freeCon();
      }
      //listDepUser.addAll(mapDepUser.values());
      return mapDepUser;
  }

private Map<Department, List<User>> coldepuser;
public void setColdepuser(Map<Department, List<User>> coldepuser) {
        this.coldepuser=coldepuser;
    }
public Map<Department, List<User>> getColdepuser() {
        return coldepuser;
    }
//跳转到部门添加页面
public String add() throws Exception {
        //HttpServletRequest request=ServletActionContext.getRequest();
        UserDao userdao=new UserDao();
        //Map<Department,List<User>> mapDepUser=new HashMap<Department,List<User>>();
        DepartmentDao departmentdao=new DepartmentDao();
        Map<Department, List<User>> colDepUser=userdao.getDepUser();
        Collection departmentcodeCol=departmentdao.getDepartmentCode();
        setDepartmentcode(departmentcodeCol);
        setColdepuser(colDepUser);
        //request.setAttribute("mapDepUser", mapDepUser);
        return "add";
    }

<p> <label>上级主管:</label>
            <s:doubleselect name="department.higherhead" list="coldepuser"
               listKey="departmentcode" listValue="departmentname" doubleList="coldepuser[top]"
               doubleName="userid" doubleListKey="userid" doubleListValue="username" theme="simple"
             />
</p>