出错，求助。为什么每次运行总是出错？

[yangjia1571525937]

public void actionPerformed(ActionEvent e){
if(e.getSource()==b3){
String a;
a=c3.getText();
String b;
b=c4.getText();
// System.out.print("xingming:"+a+" ");
// System.out.print("sex:"+b+" ");
if(a.equals("")&&b.equals("")){
JOptionPane.showMessageDialog(this, "请输入用户名和密码");
}
else{
int res=0;
try {
res=stmt.executeUpdate("insert into xue(use,password) values (a,b)");
} catch (SQLException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
JOptionPane.showMessageDialog(this, "注册成功");
}
}
if(e.getSource()==b4) {
this.dispose();
}
}



为什么执行这一段总是出现这个错误
java.sql.SQLSyntaxErrorException: ORA-00984: 列在此处不允许

at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:439)
at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:395)
at oracle.jdbc.driver.T4C8Oall.processError(T4C8Oall.java:802)
at oracle.jdbc.driver.T4CTTIfun.receive(T4CTTIfun.java:436)
at oracle.jdbc.driver.T4CTTIfun.doRPC(T4CTTIfun.java:186)
at oracle.jdbc.driver.T4C8Oall.doOALL(T4C8Oall.java:521)
at oracle.jdbc.driver.T4CStatement.doOall8(T4CStatement.java:194)
at oracle.jdbc.driver.T4CStatement.executeForRows(T4CStatement.java:1000)
at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:1307)
at oracle.jdbc.driver.OracleStatement.executeUpdateInternal(OracleStatement.java:1814)
at oracle.jdbc.driver.OracleStatement.executeUpdate(OracleStatement.java:1779)
at oracle.jdbc.driver.OracleStatementWrapper.executeUpdate(OracleStatementWrapper.java:277)
at ouyan.zhuce1.actionPerformed(zhuce1.java:98)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$400(Unknown Source)
at java.awt.EventQueue$2.run(Unknown Source)
at java.awt.EventQueue$2.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown Source)
at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)

[zbdzjx]

res=stmt.executeUpdate("insert into xue(use,password) values (’“+a+”‘,’“+b+”‘)");

[yangjia1571525937]

为什么要这样写啊？

[卖水果的net]

values(a，b) a，b是什么？显然什么也不是，因为你要写你指定的值。