数据库中的故障和java中的数据库检查
我在检查ms access数据库中的用户名时遇到问题数据库中的故障和java中的数据库检查,java,ms-access,jdbc,jdbc-odbc,Java,Ms Access,Jdbc,Jdbc Odbc,我在检查ms access数据库中的用户名时遇到问题 java.sql.SQLException: No data found 这是数据库连接 public class dbAccess { Connection conn; ResultSet rs; Statement s; PreparedStatement ps; public void doConnect() { try {
java.sql.SQLException: No data found
这是数据库连接
public class dbAccess
{
Connection conn;
ResultSet rs;
Statement s;
PreparedStatement ps;
public void doConnect()
{
try
{
String driver = "sun.jdbc.odbc.JdbcOdbcDriver";
Class.forName(driver);
String login = "jdbc:odbc:Driver={Microsoft Access Driver (*.mdb, *.accdb)};DBQ=E:\\File Kuliah\\Semester 7\\AOOP\\JavaApplication1\\build\\classes\\Database1.accdb";
conn = DriverManager.getConnection(login);
System.out.println("Connected");
}
catch(Exception ex)
{
ex.printStackTrace();
}
}
}
下面是出现错误的代码
private void registerButtonActionPerformed(java.awt.event.ActionEvent evt) {
try
{
db.ps = db.conn.prepareStatement("SELECT * FROM DatabaseAOOP");
db.rs = db.ps.executeQuery();
System.out.print("1");
while(db.rs.next())
{
if(userRegis.getText().equals(db.rs.getString("username")))
{
System.out.print("3");
JOptionPane.showMessageDialog(this, "Username is already exists !");
userRegis.setText("");
passRegis.setText("");
//db.rs=null;
//db.ps=null;
break;
}
else if(userRegis.getText().isEmpty())
{
JOptionPane.showMessageDialog(this, "Please input the name");
}
else if(!userRegis.getText().equals(db.rs.getString("username")))
{
JOptionPane.showMessageDialog(this, "Searching ...");
}
else
{
System.out.print("2");
db.ps = db.conn.prepareStatement("INSERT INTO DatabaseAOOP(username,password) VALUES(?,?)");
db.s = db.conn.createStatement();
db.ps.setString(1, userRegis.getText());
db.ps.setString(2, passRegis.getText());
db.ps.executeUpdate();
JOptionPane.showMessageDialog(this, "Thank you for registering !");
userRegis.setText("");
passRegis.setText("");
break;
}
}
}
catch(Exception ex)
{
ex.printStackTrace();
System.out.println(ex);
}
}
这是printstacktrace
at sun.jdbc.odbc.JdbcOdbc.SQLGetDataString(JdbcOdbc.java:3914)
at sun.jdbc.odbc.JdbcOdbcResultSet.getDataString(JdbcOdbcResultSet.java:5697)
at sun.jdbc.odbc.JdbcOdbcResultSet.getString(JdbcOdbcResultSet.java:353)
at sun.jdbc.odbc.JdbcOdbcResultSet.getString(JdbcOdbcResultSet.java:410)
at Frame.registerButtonActionPerformed(Frame.java:277)
at Frame.access$600(Frame.java:4)
at Frame$7.actionPerformed(Frame.java:135)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2018)
at javax.swing.AbstractButton$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:6516)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3320)
at java.awt.Component.processEvent(Component.java:6281)
at java.awt.Container.processEvent(Container.java:2229)
at java.awt.Component.dispatchEventImpl(Component.java:4872)
at java.awt.Container.dispatchEventImpl(Container.java:2287)
at java.awt.Component.dispatchEvent(Component.java:4698)
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:4698)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:735)
at java.awt.EventQueue.access$200(EventQueue.java:103)
at java.awt.EventQueue$3.run(EventQueue.java:694)
at java.awt.EventQueue$3.run(EventQueue.java:692)
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:708)
at java.awt.EventQueue$4.run(EventQueue.java:706)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:705)
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)
实际上,我刚刚检查了连接的数据库,但是在进入
while(db.rs.next())
循环调用db.rs.getString(“用户名”)
后,没有立即找到数据,然后在循环中再次调用db.rs.getString(“用户名”)
。这是引发“未找到数据”异常的第二次调用
在许多情况下,JDBC只允许我们对ResultSet中给定(当前)行的每列调用一次get…
方法。您应该将该值保存为字符串
String theUserName=db.rs.getString(“用户名”);
然后使用字符串变量进行(多次)比较。输入
后立即调用db.rs.getString(“用户名”)
,然后在循环中再次调用db.rs.getString(“用户名”)
。这是引发“未找到数据”异常的第二次调用
在许多情况下,JDBC只允许我们对ResultSet中给定(当前)行的每列调用一次get…
方法。您应该将该值保存为字符串
String theUserName=db.rs.getString(“用户名”);
然后使用字符串变量进行(多次)比较。我刚刚将其更改为字符串theUserName,但现在出现以下错误:java.sql.SQLException:[Microsoft][ODBC Driver Manager]无效光标状态我刚刚将其更改为字符串theUserName,但现在出现以下错误:java.sql.SQLException:[Microsoft][ODBC Driver Manager]无效的游标状态