功能介绍
课室查询功能，是用于查询某一时间、某一栋教学楼空闲的教室，查询到的教室有教室编号和教室大小，教室位置等信息，通过这些信息可以选择是否借用教室。
功能实现原理
通过选择多个信息进行数据库的数据匹配，然后筛选出所需要的数据，例如教室是否有课，有人借用，若有，则是不能显示在表格中的，显示在表格中的教室都是可借用教室。
课室查询功能
/*
* 查询指定教学楼、指定人数、指定星期节次没课时的数据
*/
public List<ClassData> queryClass(String lou,String scale,int week,String day,String node){
String sql = "select CRno,CRscale,CRlocation from RoomData where CRno NOT in (SELECT ClassData.CRno FROM RoomData,ClassData where RoomData.CRno=ClassData.CRno and CRlocation like '"+lou+"%' and CRscale = "+scale+" and CweekF<="+week+" and CweekL>="+week+" and Cday like '__"+day+"' and Cnode like '"+node+"') and CRscale = "+scale+" and CRlocation like '"+lou+"%' and CRno not in (select classNo from BCRegister where classNo in (SELECT classNo from RoomData,BCRegister where RoomData.CRno=BCRegister.classNo and CRlocation like '"+lou+"%' and CRscale = "+scale+" and BCweek="+week+" and BCday like '"+day+"' and BCnode like '"+node+"') and BCweek = "+week+" and BCday like '"+day+"' and BCnode like '"+node+"')";
List<ClassData> list = new ArrayList<ClassData>();
Connection con = null;
PreparedStatement pst = null;
ResultSet rs = null;
ClassData user=null;
try {
//通过帮助类获取数据库链接对象
con=DBUtils.getConnection();
pst =con.prepareStatement(sql);
rs =pst.executeQuery();
//遍历结果集
while(rs.next()){
user =new ClassData();
user.setCRno(rs.getString(1));
user.setCRscale(rs.getInt(2));
user.setCRlocation(rs.getString(3));
/*user.setCweek(rs.getString(4));
user.setCday(rs.getString(5));
user.setCnode(rs.getString(6));
*/
list.add(user);
}
} catch (SQLException e) {
e.printStackTrace();
}
return list;
}
查询功能界面：
通过教学楼，人数，时间来确定能借用的教室
总结
在该部分功能的实现时，遇到的问题有两个。
第一：字符串后面有空格，导致无法匹配成功，在登陆注册功能时也会有这样的情况，解 决办法是要去掉后面的空格，方法如下：
/*
* 去掉字符串末尾的空格方法
*/
public static String rtrim(String value){
if(value==null)
return null;
return value.replaceAll("\\s+$","");
}
第二：筛选逻辑有问题，我们需要是某时间，某容量的教室没有课的教室，所以匹配到某时间，某容量有课的教室都是不能显示的，在这个问题上逻辑要理顺，要层层递进。
"select CRno,CRscale,CRlocation from RoomData
where CRno NOT in (SELECT ClassData.CRno FROM RoomData,ClassData
where RoomData.CRno=ClassData.CRno and CRlocation like '"+lou+"%' and CRscale = "+scale+" and CweekF<="+week+" and CweekL>="+week+" and Cday like '__"+day+"' and Cnode like '"+node+"')
and CRscale = "+scale+" and CRlocation like '"+lou+"%'
and CRno not in (select classNo from BCRegister
where classNo in (SELECT classNo from RoomData,BCRegister
where RoomData.CRno=BCRegister.classNo and CRlocation like '"+lou+"%' and CRscale = "+scale+" and BCweek="+week+" and BCday like '"+day+"' and BCnode like '"+node+"') and BCweek = "+week+" and BCday like '"+day+"' and BCnode like '"+node+"')"
需要程序源码请查看本人资源
