public class JDBCtest02 {
public static void main(String[] args) {
Connection conn=null;
PreparedStatement ps=null;
ResultSet rs=null;
try {
Class.forName("com.mysql.cj.jdbc.Driver");
conn= DriverManager.getConnection("jdbc:mysql://localhost:3306/class","root","123456");//这是一个工具方法
String sql="select ? from class"; //DQL语句
ps=conn.prepareStatement(sql); //编译
ps.setString(1,"name"); //输入占位符
rs=ps.executeQuery(); //执行
while (rs.next()){ //遍历
String aname=rs.getString(1);
System.out.println(aname);
}
} catch (Exception e) {
e.printStackTrace();
}finally {
JDBCUtil.close(conn,ps,rs);//释放方法
}
}
}