Question

这是我的程序..当我单击确定按钮时，代码显示...

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at Masters.DesignationMaster.actionPerformed(DesignationMaster.java:423)
    at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2018)
    at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2341)
    at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
    at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
    at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
    at java.awt.Component.processMouseEvent(Component.java:6505)
    at javax.swing.JComponent.processMouseEvent(JComponent.java:3321)
    at java.awt.Component.processEvent(Component.java:6270)
    at java.awt.Container.processEvent(Container.java:2229)
    at java.awt.Component.dispatchEventImpl(Component.java:4861)
    at java.awt.Container.dispatchEventImpl(Container.java:2287)
    at java.awt.Component.dispatchEvent(Component.java:4687)
    at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4832)
    at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4492)
    at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4422)
    at java.awt.Container.dispatchEventImpl(Container.java:2273)
    at java.awt.Window.dispatchEventImpl(Window.java:2719)
    at java.awt.Component.dispatchEvent(Component.java:4687)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:729)
    at java.awt.EventQueue.access$200(EventQueue.java:103)
    at java.awt.EventQueue$3.run(EventQueue.java:688)
    at java.awt.EventQueue$3.run(EventQueue.java:686)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87)
    at java.awt.EventQueue$4.run(EventQueue.java:702)
    at java.awt.EventQueue$4.run(EventQueue.java:700)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:699)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:242)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:161)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:150)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:138)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:91)

//我的程序

DELIMITER $$
CREATE DEFINER=`root`@`localhost` PROCEDURE `desig_procedure`(

    IN designation_id       int(10), 

    IN designation_name     varchar(20)

)
BEGIN
    insert into designation_master
(
    designation_id,
    designation_name
)
VALUES
(
    designation_id,
    designation_name
);

END

// Java代码

if(!"".equals(editDesignationIDTextField.getText()) && !"".equals(editDesignationNameTextField.getText()))
        {
            con= new InitializeDatabase();
            //con.getConnection();
                try
                {
                    CallableStatement stmt=(CallableStatement) con.connection.prepareCall("{call desig_procedure(?,?)}");
                    stmt.setString("" + editDesignationIDTextField.getText(),"" + editDesignationNameTextField.getText());
                    stmt.execute();

                }
                catch (SQLException ex)
                {
                    ex.printStackTrace();
                }
                finally
                {
                    try {
                        if(con.connection != null && !con.connection.isClosed())
                        {
                            con.connection.close();
                        }
                    } catch (SQLException ex) 
                    {
                        ex.printStackTrace();
                    }
                }
            }
      }

问题在哪里我得到了这个错误..我有连接...并且工作正常因此从文件InitialiseDatabse.java ...请帮助..

Answer 1

问题在于：

stmt.setString("" + editDesignationIDTextField.getText(),
    "" + editDesignationNameTextField.getText());

您没有以正确的方式设置参数：

stmt.setString(1, "" + editDesignationIDTextField.getText());
stmt.setString(2, "" + editDesignationNameTextField.getText());

注意，您的String转换有效但不是最佳方式。由于getText方法已经返回String，因此您不需要"" +部分：

stmt.setString(1, editDesignationIDTextField.getText());
stmt.setString(2, editDesignationNameTextField.getText());

插入存储过程

1 个答案: