1

谁能看到我错过了这个 ResultSet 吗？我收到以下错误customerID = rs.getInt(1)：

public boolean addCustomer(Customer customer) {
    String customerSQL = "INSERT INTO Customer (first_name, last_name)"
            + "VALUES (?, ?)";
    String emailSQL = "INSERT INTO Email (customer_ID, email_address, primary_email)"
            + "VALUES (?,?,?)";
    int customerID = 0;

    try (Connection connection = getConnection();
            PreparedStatement customerPs = connection.prepareStatement(
                    customerSQL, new String[] {"CUSTOMER_ID"});
            //PreparedStatement idPs = connection.prepareStatement(idSQL);
            //PreparedStatement emailPs = connection.prepareStatement(emailSQL)
            )  {

        customerPs.setString(1, customer.getFirstName());
        customerPs.setString(2, customer.getLastName());
        customerPs.executeUpdate();
        ResultSet rs = customerPs.getGeneratedKeys();

        System.out.println("Result Set: " + rs.toString());
        customerID = rs.getInt(1);
        System.out.print("Customer ID: " + customerID);



    }
    catch(SQLException e)
    {
        System.err.println("Error: " + e);
        e.printStackTrace(System.out);
        return false;
    }

    return false;
}

输出

run:
Bill Joel
this@that.com
those@these.com
wank@that.com

Result Set: org.apache.derby.impl.jdbc.EmbedResultSet40@61c70928
Error: java.sql.SQLException: Invalid cursor state - no current row.
java.sql.SQLException: Invalid cursor state - no current row.
        at org.apache.derby.impl.jdbc.SQLExceptionFactory40.getSQLException(Unknown Source)
        at org.apache.derby.impl.jdbc.Util.newEmbedSQLException(Unknown Source)
        at org.apache.derby.impl.jdbc.Util.newEmbedSQLException(Unknown Source)
        at org.apache.derby.impl.jdbc.Util.generateCsSQLException(Unknown Source)
        at org.apache.derby.impl.jdbc.EmbedConnection.newSQLException(Unknown Source)
        at org.apache.derby.impl.jdbc.ConnectionChild.newSQLException(Unknown Source)
        at org.apache.derby.impl.jdbc.EmbedResultSet.checkOnRow(Unknown Source)
        at org.apache.derby.impl.jdbc.EmbedResultSet.getColumn(Unknown Source)
        at org.apache.derby.impl.jdbc.EmbedResultSet.getInt(Unknown Source)
        at customeremailmanager.CustomerDB.addCustomer(CustomerDB.java:78)
        at customeremailmanager.CustomerEmailManager.main(CustomerEmailManager.java:24)
Caused by: java.sql.SQLException: Invalid cursor state - no current row.
        at org.apache.derby.impl.jdbc.SQLExceptionFactory.getSQLException(Unknown Source)
        at org.apache.derby.impl.jdbc.SQLExceptionFactory40.wrapArgsForTransportAcrossDRDA(Unknown Source)
        ... 11 more
BUILD SUCCESSFUL (total time: 1 second)
4

2 回答 2

5

在从 ResultSet 对象中检索行之前，您必须调用ResultSet.next() ：

ResultSet rs = customerPs.getGeneratedKeys();
           while(rs.next()){
            System.out.println("Result Set: " + rs.toString());
            customerID = rs.getInt(1);
}
于 2012-12-02T22:54:02.080 回答
0

您需要首先确保行可用。请参阅本教程，了解如何使用 ResultsSet 检索数据。

根据文档：

您可以通过游标访问 ResultSet 对象中的数据。请注意，此游标不是数据库游标。此游标是指向 ResultSet 中的一行数据的指针。最初，光标位于第一行之前。ResultSet.next 方法将光标移动到下一行。如果光标位于最后一行之后，则此方法返回 false。该方法通过while循环重复调用ResultSet.next方法来遍历ResultSet中的所有数据

例子：

while (rs.next()) {
       customerID = rs.getInt(1);
     }
于 2012-12-02T22:54:58.263 回答