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