我的java bean设计得对吗?
qabp 2004-05-03 01:06:42 简单例子,与问题无关的都已省略:
/**部门表:department **/
create table Department(
DepNo char(9), /**主键,部门代号**/
DepUpperNo char(9) /**上级部门代号,无上级部门时为空**/
);
/* entry bean */
class Department{
private String depno;
Department depupper; //若无上级部门,为空
//....
//setters and getters
}
/* bean to operate the database */
class DepartmentMap{
public DepartmentMap(){}
public Department load(String DepNo){
//...Connect the database and construct the string sql
ResultSet rs=db.executeQuery(sql);
Department dep,depupper;
dep.setDepNo(rs.getString("DepNo"));
if (rs.getString("DepUpper")!=null){
DeparmtentMap dm;
depupper=dm.load(rs.getDate("DepUpper"));
}
else depupper=null;
dep.setDepDepUpper(depupper);
return dep;
}
//other functions...
}
调用load函数时,会递归执行下去,把所有的上级部门都实例化了,好象没有这个必要,很耗时啊。我这样设计对不对呢?不对,又该怎么改?
顺便问一句,DepartmentMap是不是设计成abstract class好一点?