Question

我正在尝试通过ucanaccess jdbc在MS Access表中插入以下代码。它给出了以下例外。我被困在我做错的地方。例外是：

>net.ucanaccess.jdbc.UcanaccessSQLException: UCAExc:::3.0.3 java.lang.NullPointerException java.lang.NullPointerException
    at net.ucanaccess.jdbc.UcanaccessStatement.executeQuery(UcanaccessStatement.java:211)   at net.ucanaccess.jdbc.UcanaccessStatement.executeQuery(UcanaccessStatement.java:211)
    at insertdata.jButton1ActionPerformed(insertdata.java:197)
    at insertdata.access$200(insertdata.java:15)
    at insertdata$3.actionPerformed(insertdata.java:64)
    at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
    at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2346)
    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.AWTEventMulticaster.mouseReleased(AWTEventMulticaster.java:289)
    at java.awt.Component.processMouseEvent(Component.java:6525)
    at javax.swing.JComponent.processMouseEvent(JComponent.java:3321)
    at java.awt.Component.processEvent(Component.java:6290)
    at java.awt.Container.processEvent(Container.java:2234)
    at java.awt.Component.dispatchEventImpl(Component.java:4881)
    at java.awt.Container.dispatchEventImpl(Container.java:2292)
    at java.awt.Component.dispatchEvent(Component.java:4703)
    at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4898)
    at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4533)
    at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4462)
    at java.awt.Container.dispatchEventImpl(Container.java:2278)
    at java.awt.Window.dispatchEventImpl(Window.java:2739)
    at java.awt.Component.dispatchEvent(Component.java:4703)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:746)
    at java.awt.EventQueue.access$400(EventQueue.java:97)
    at java.awt.EventQueue$3.run(EventQueue.java:697)
    at java.awt.EventQueue$3.run(EventQueue.java:691)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:86)
    at java.awt.EventQueue$4.run(EventQueue.java:719)
    at java.awt.EventQueue$4.run(EventQueue.java:717)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:716)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)
Caused by: java.sql.SQLException: java.lang.NullPointerException java.lang.NullPointerException
    at org.hsqldb.jdbc.JDBCUtil.sqlException(Unknown Source)
    at org.hsqldb.jdbc.JDBCUtil.sqlException(Unknown Source)
    at org.hsqldb.jdbc.JDBCStatement.fetchResult(Unknown Source)
    at org.hsqldb.jdbc.JDBCStatement.executeQuery(Unknown Source)
    at net.ucanaccess.jdbc.UcanaccessStatement.executeQuery(UcanaccessStatement.java:208)
    ... 40 more
Caused by: org.hsqldb.HsqlException: java.lang.NullPointerException
    at org.hsqldb.error.Error.error(Unknown Source)
    at org.hsqldb.result.Result.newErrorResult(Unknown Source)
    at org.hsqldb.StatementDMQL.execute(Unknown Source)
    at org.hsqldb.Session.executeCompiledStatement(Unknown Source)
    at org.hsqldb.Session.executeDirectStatement(Unknown Source)
    at org.hsqldb.Session.execute(Unknown Source)
    ... 43 more
Caused by: java.lang.NullPointerException
    at net.ucanaccess.jdbc.UcanaccessConnection.getCtxConnection(UcanaccessConnection.java:81)
    at net.ucanaccess.triggers.TriggerAutoNumber.fire(TriggerAutoNumber.java:39)
    at org.hsqldb.TriggerDef.pushPair(Unknown Source)
    at org.hsqldb.Table.fireTriggers(Unknown Source)
    at org.hsqldb.StatementDML.insertSingleRow(Unknown Source)
    at org.hsqldb.StatementInsert.getResult(Unknown Source)
    ... 47 more

任何建议如何解决这个问题。我的查询是否会产生问题？

代码

 private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         

        try{
            conn=DriverManager.getConnection("jdbc:ucanaccess://E:/cars.accdb");
            st=conn.createStatement();
             String name=tname.getText();
             String email=temail.getText();
             int phone=Integer.parseInt( tphone.getText());

             String sql="insert into customers ([name],[email],[phone]) values('name','email',phone)";
            rs= st.executeQuery(sql);
             if(rs.next())
             {
                System.out.println("updated!!");
             }
              st.close();
              conn.close();
        }
         catch(Exception e){

        System.out.println(e);

    }
    }

Answer 1

您的错误是您使用executeQuery执行SQL INSERT。

使用

st.executeUpdate(sql);

代替。

不幸的是，JDBC驱动程序没有给你一个正确的错误信息，但显然在其内部深处失败。

插入Ms访问表时出现空指针异常

1 个答案: