Java 检查变量是否为 AG。如果没有，显示错误信息并再次询问

我正在尝试编写一个程序来计算音阶。不幸的是，我遇到了一个问题。我需要一种方法来检查输入值是否是音阶上的音符之一。如果是，请将其转换为数字以供以后计算。如果没有，则显示错误并再次询问。我尝试这样做，即使我给出了有效的注释，它也会使我陷入无限循环。有什么帮助吗？我的代码：

    package music;

import java.util.Scanner;

import javax.swing.JOptionPane;

public class musicc {
    public static void main(String[] args) throws Exception {
        int noteid;
        noteid = musicc.getNoteId();
    }

    public static int getNoteId() {
        String note = "0";
        int returnValue = 0;
        note = (String)JOptionPane.showInputDialog(null,"What note do you want to start on?",JOptionPane.PLAIN_MESSAGE);

        while (note != "A" && note != "B" && note != "C" && note != "D" && note != "E" && note != "F" && note != "G") {
            JOptionPane.showMessageDialog(null, note + " is not a valid note! Try again.", "Invalid note!", JOptionPane.ERROR_MESSAGE);
            note = (String)JOptionPane.showInputDialog(null,"What note do you want to start on?",JOptionPane.PLAIN_MESSAGE);
        }
        switch(note) {
        case "A":return 1; 
        case "B":return 2;
        case "C":return 3; 
        case "D":return 4; 
        case "E":return 5; 
        case "F":return 6; 
        case "G":return 7; 
        }
        return 0;       
    }
}