java - ActionListerner 中的 ClassNotFoundException

Question

我的按钮操作监听器中有以下错误未报告的异常 ClassNotFoundException ，我不确定如何解决它，我尝试添加 Throw ClassNotFoundException 但它仍然是尝试编译时出现错误，我将其添加到

public void actionPerformed(ActionEvent e) throw ClassNotFoundException {
//action listeners for Login in button and menu item
        submitButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                try {

                    DisplaySearch.Search(jtfImagename.getText(), jtfLocation.getText(), jtfTimestamp.getText());

                    String Iname = jtfImagename.getText();
                    String Loc = jtfLocation.getText();
                    String Time = jtfTimestamp.getText();
                    accountReportArea.setText("Search Criteria \n" + "Image name : " + Iname + "\nLocation : " + Loc + "\nTime Stamp : " + Time);                 
                } catch (SQLException ex) {
                    ex.printStackTrace();
                    //    JOptionPane.showMessageDialog(null,
                    //            "Sorry, couldn't check your credentials. Check the logs and report the problem to an administrator.");
                    return;
                }
            }
        });

DisplaySearch {
    // database URL                              

    static final String DATABASE_URL = "jdbc:mysql://localhost:3306/mysql";
    static final String USERNAME = "root";
    static final String PASSWORD = "root";

    // launch the application
    public static void Search(String imageName, String DateStamp, String imageTag) throws ClassNotFoundException, InstantiationException, IllegalAccessException {
        Connection connection = null; // manages connection
        Statement statement = null; // query statement
        ResultSet resultSet = null; // manages results

        // connect to database books and query database
        try {
            // establish connection to database
            Class.forName("com.mysql.jdbc.Driver").newInstance();
            connection = DriverManager.getConnection(DATABASE_URL, USERNAME, PASSWORD);

            // create Statement for querying database
            statement = connection.createStatement();

            // query database                                        
            resultSet = statement.executeQuery(
                    "SELECT imageName, DateStamp, imageTag FROM images");

            // process query results   
            System.out.println("Search Criteria");

            while (resultSet.next()) {
                String Tag = resultSet.getString(imageTag);
                String Date = resultSet.getString(DateStamp);
                String Name = resultSet.getString(imageName);
                System.out.print("Image Name: " + Name);
                System.out.print(", Date: " + Date);
                System.out.print(", Tag: " + Tag);
            } // end while
        } // end try
        catch (SQLException sqlException) {
            sqlException.printStackTrace();
        } // end catch                                                     
        finally // ensure resultSet, statement and connection are closed
        {
            try {
                resultSet.close();
                statement.close();
                connection.close();
            } // end try                                               
            catch (Exception exception) {
                exception.printStackTrace();
            } // end catch                                             
        } // end finally                                              
    } // end main
} // end class

Answer 1

通过添加抛出ClassNotFoundException，您不会解决任何问题。您只需向调用此函数的人表明，它可能抛出这样的异常。

由于您使用的是Class.forName()，因此您应该在运行时包含com.mysql.jdbc.Driver。也许您的类路径中缺少 JAR？