Java JDBC First() 在 ResultSet 中不起作用？

我想将光标的位置更改为第一行，但我不知道为什么我的代码不起作用。当我添加时rs2.first():

我还收到此错误：

仅应在可滚动的 ResultSet 对象（类型 TYPE_SCROLL_INSENSITIVE）上调用此方法。

        try{                    
      String driver = "org.apache.derby.jdbc.ClientDriver";
      Class.forName(driver).newInstance();
      String url = "jdbc:derby://localhost:1527/test";
      Connection conn = DriverManager.getConnection(url);
      String query = "select * from APP.RANKING";
      Statement stmt = conn.createStatement();
      Statement stmt2 = conn.createStatement();
      ResultSet rs = stmt.executeQuery(query);
      ResultSet rs2 = stmt2.executeQuery(query);
      while (rs.next()){             
          String BID = rs.getString("BALLOT_ID");
          String CN = rs.getString("CANDIDATE_NAME");
          String ROID = rs.getString("USER_ID");
          Ro1_ID = ROID;
          String RA = rs.getString("RANK");
          int rowNum = rs.getRow();
          int rowNum2;
          boolean In_check = false;
          while(rs2.next()){               
                  In_ballot.addElement(BID);  
                  
                }

          rs2.First();
          In_ballot.addElement(BID);  
              }
         
         }
    catch(Throwable e) {
                System.err.println(e.getMessage());        
                }
    this.InB_list.setModel(In_ballot);

默认情况下，调用createStament() http://docs.oracle.com/javase/6/docs/api/java/sql/Connection.html#createStatement%28%29在每个连接结果中ResultSet具有类型“TYPE_FORWARD_ONLY” - 这会导致您使用时看到的异常first() http://docs.oracle.com/javase/6/docs/api/java/sql/ResultSet.html#first%28%29.

相反，使用其他版本createStatement, like this one http://docs.oracle.com/javase/6/docs/api/java/sql/Connection.html#createStatement%28int,%20int%29.

这个样本 http://docs.oracle.com/javadb/10.4.2.1/devguide/cdevconcepts22641.html创建可滚动的ResultSet德比的比赛可能会有所帮助。