我正在尝试通过JFrame将数据插入MySQL

问题描述 投票:0回答:1

我一直在尝试使用MySQL数据库将数据插入到JFrame注册表中。但我得到的只是我不知道的错误。这是我的SQL代码和正在显示的错误。

有人可以帮我解决这个错误吗?

 JButton btnNewButton = new JButton("Sign Up");
    btnNewButton.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            String url = "jdbc:mysql://localhost:3306/login";
            String user ="root";
            String password ="toor";

            try {
                Class.forName("com.mysql.cj.jdbc.Driver");
                Connection conn = DriverManager.getConnection(url, user, password);
                Statement state = conn.createStatement();
                  String username = textField.getText();
                  String email=textField_1.getText();
                  String password1 = new String(passwordField.getPassword());
                  String password2 = new String(passwordField_1.getPassword());


                String insertTableSQL = "INSERT INTO signup"+"(username,email,password,confirm) VALUES"+"(?,?,?,?)";
                PreparedStatement create = conn.prepareStatement(insertTableSQL);

                create.setString(1, username);
                create.setString(2, email);
                create.setString(3, password);
                create.setString(4, password);
                create.executeUpdate(insertTableSQL);

                state.executeQuery(insertTableSQL);


            }catch(Exception arg0) {arg0.printStackTrace();
            System.out.println("Success");
        ;}
    }});

堆栈跟踪

 Success
java.sql.SQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '?,?,?,?)' at line 1
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:120)
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97)
    at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:122)
    at com.mysql.cj.jdbc.StatementImpl.executeUpdateInternal(StatementImpl.java:1355)
    at com.mysql.cj.jdbc.StatementImpl.executeLargeUpdate(StatementImpl.java:2128)
    at com.mysql.cj.jdbc.StatementImpl.executeUpdate(StatementImpl.java:1264)
    at SignUp$5.actionPerformed(SignUp.java:144)
    at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
    at javax.swing.AbstractButton$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$500(Unknown Source)
    at java.awt.EventQueue$3.run(Unknown Source)
    at java.awt.EventQueue$3.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
    at java.awt.EventQueue$4.run(Unknown Source)
    at java.awt.EventQueue$4.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.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)
java mysql sql swing jframe
1个回答
1
投票
insertTableSQL = "INSERT INTO signup"+"(username,email,password,confirm) VALUES"+"(?,?,?,?)";

使用PreparedStatement的关键是你可以只使用带有SQL的简单字符串,然后用实际参数替换标记。

在上面的SQL中,您使用的是字符串连接,这是不必要的。只需使用:

insertTableSQL = "INSERT INTO signup(username,email,password,confirm) VALUES(?,?,?,?)";

这使得它更容易阅读,并且在添加所有分隔符时不太可能使输入错误。

但是,我怀疑这是问题所在。

相反,我看到:

String password1 = new String(passwordField.getPassword());
String password2 = new String(passwordField_1.getPassword());

然而,您然后使用:

create.setString(3, password);
create.setString(4, password);

替换令牌。我猜“密码”是空的?

也许你应该使用“password1”和“password2”?

编辑:

你有几个问题。看看你的代码:

Statement state = conn.createStatement();
String insertTableSQL = "INSERT INTO signup(username,email,password,confirm) VALUES(?,?,?,?)";
PreparedStatement create = conn.prepareStatement(insertTableSQL);

...

create.executeUpdate(insertTableSQL);
state.executeQuery(insertTableSQL);
  1. 您创建两个语句
  2. 您尝试执行“插入”SQL命令作为查询。

解决方案是:

  1. 摆脱声明。
  2. 摆脱executeQuery。

如果要在插入后执行查询,则需要使用“Select”语句创建单独的SQL查询。

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