Question

为什么模报的时候总是查询结果为空

Answer 1

Connection con = null ;
数据库连接语句自己写！！

String sql = "select * from tbl_user" ;
try{
PreparedStatement ps = con.PrepareStatement(sql);
ResultSet rs = ps.executeQuery();

if(rs.next()){
System.out.println("不为null");
}else{
System.out.println("null");
}
ps.close();
}catch(Exception err){}
finally{
try{
con.close();
}catch(Exception e){}
}