关于java.lang.NullPointerException的一个问题.
Connection conn = null;
PreparedStatement pstmt = null;
ResultSet rs = null;
String sql = "";
sql = "select pkid, title, father from dir_article where pkid='" +
father + "'";
pstmt = conn.prepareStatement(sql);
rs = pstmt.executeQuery();
while (rs.next())
{
System.out.println(rs.getString("title"));
}
这样子的一段JAVA语句,SQl是肯定可以查到一条记录的,可是在执行rs.next()时却老是出现:java.lang.NullPointerException
请问这是什么原因,有什么办法可以解决??
谢谢.