[高分求解]ORACLE JDBC联接 取不到表数据

        try {            Class.forName("oracle.jdbc.driver.OracleDriver");            String url = "jdbc:oracle:thin:@localhost:1521:orcl";            String user = "yongning";            String password = "yongning";            Connection conn = DriverManager.getConnection(url,user,password);            DatabaseMetaData dmd = conn.getMetaData();            System.out.println(dmd.getDatabaseMajorVersion());            System.out.println(dmd.getDatabaseProductName());            Statement stmt = conn.createStatement();            ResultSet rs = stmt.executeQuery("select * from test_book1");            ResultSetMetaData rsmd = rs.getMetaData();            int columnCount = rsmd.getColumnCount();            System.out.println(columnCount);//             for(int i = 1; i <= columnCount; i++){                    //把列名打印在一行,每个列名之间间隔一个制表位(\t)                    System.out.print(rsmd.getColumnName(i)+"\t");                  }                  System.out.println();                  System.out.println("-----------------------------");                  while(rs.next()){                    //数据表的一行                    System.out.println("奶奶的，就是不给我输出");                    for(int i = 1; i <= columnCount; i++){                      //一行中的每个列                      System.out.print(rs.getString(rsmd.getColumnName(i)) + "\t");                    }                    System.out.println();                  }                                }catch(Exception e){                  e.printStackTrace();                }    }

create table test_book1(id number,bookname varchar(64));insert into test_book1 values('1','我我我');select * from test_book1;   ID BOOKNAME----- -------------------------    1 我我我