• 我为选项创建了一个字符串数组 * 是的。使用这个数组。假设它被称为possibleChoices，它可能看起来像

private static String[] possibleChoices = {
        "Dollars to Pesos",
        "Pesos to Dollars",
        "Dollars to GB Pounds",
        "GB Pounds to Dollars",
        "Dollars to Yen",
        "Yen to Dollars"
};

@Override
public void actionPerformed(ActionEvent e) {
    String text = textField.getText();
    double c = Double.parseDouble(text);
    if (e.getSource() == comboBox) {
        String choice = comboBox.getSelectedItem().toString();
        if (Arrays.stream(possibleChoices).anyMatch(choice::equalsIgnoreCase)) {
            System.out.println(choice);
        }
    }
}

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Java 8或更高版本可以使用函数接口的Map来创建更灵活的解决方案，如下所示，

Map<String, Runnable> map = new HashMap<>();
map.put("dollars to pesos", () -> System.out.println("Dollars to Pesos"));
map.put("pesos to dollars", () -> System.out.println("Pesos to Dollars"));
map.put("dollars to gb pounds", () -> System.out.println("Dollars to GB Pounds"));
map.put("gb pounds to dollars", () -> System.out.println("GB Pounds to Dollars"));
map.put("dollars to yen", () -> System.out.println("Dollars to Yen"));
map.put("yen to dollars", () -> System.out.println("Yen to Dollars"));

@Override
public void actionPerformed(ActionEvent e) {
    if(e.getSource()==comboBox) {
        String choice = comboBox.getSelectedItem().toString().toLowerCase();
        Runnable runnable = map.get(choice);
        if (runnable != null) {
            runnable.run();
        }
    }
}

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这种方法的另一个好处是，只需在Map中添加或删除条目，就可以轻松地添加或删除货币转换，而不必触及actionPerformed方法中的逻辑。如果您预计转换列表在未来会增长，则它更具可扩展性。