JDBC查看Preparedstatement执行的sql语句

通过JDBC4查看

String sql = "select * from user where uname = ?";
//执行sql语句
ps=conn.prepareStatement(sql);
ps.setString(1, uname);
res = ps.executeQuery();
String rsq = ((JDBC4PreparedStatement)ps).asSql();
System.out.println(rsq);