Question

rs.next()=false怎么回事？我用的是 SQL Server 2005 SQL语句在数据库里可以查询出来

public Teacher selectTeaByTId(String TId) {
Teacher teacher=null;
conn=getConn();
sql="select TName,TPassWord,TZC from teachers where TId='"+TId+"'";
try {
pstmt=conn.prepareStatement(sql);
rs=pstmt.executeQuery();
if(rs.next())
{
System.out.println("jinru");
teacher=new Teacher();
teacher.setTname(rs.getString("TName"));
teacher.setTpassWord(rs.getString("TPassWord"));
teacher.setTzc(rs.getString("TZC"));
}
} catch (Exception e) {
e.printStackTrace();
}
finally{
this.closeAll();
}
return teacher;
}

Answer 1

sql="select TName,TPassWord,TZC from teachers where TId='"+TId+"'";
这个地方貌似有问题，你在这里设置一个断点，等执行到这里的时候，截取下sql语句，看还能不能在sql里面运行。

Answer 2

没查到数据
===============================
public Teacher selectTeaByTId(String TId) {
Teacher teacher=null;
conn=getConn();
------------------------------------
在这中间,把你传过来的id打印一下System.out.println(TId);
看看传过来的id是什么值!
-------------------------------------
sql="select TName,TPassWord,TZC from teachers where TId='"+TId+"'";
-----------------------------------
SQL语句可以修改成这样看看!
sql="select TName,TPassWord,TZC from teachers where TId LIKE'"+TId+"'";

Answer 3

注意大小写