第三方開源庫：漢語拼音

public class PinYinUtil {

    public static String toPinYin(String text) {
        HanyuPinyinOutputFormat format = new HanyuPinyinOutputFormat();
        format.setToneType(HanyuPinyinToneType.WITHOUT_TONE);
        format.setCaseType(HanyuPinyinCaseType.UPPERCASE);//
        format.setVCharType(HanyuPinyinVCharType.WITH_V);

        StringBuilder sb = new StringBuilder();
        char[] chars = text.toCharArray();
        for (char aChar : chars) {

            if (Character.isWhitespace(aChar)) {
                continue;
            }
            if (aChar >= -128 && aChar <= 127) {
                sb.append(aChar);
            } else {
                String s = null;
                try {
                    s = PinyinHelper.toHanyuPinyinStringArray(aChar, format)[0];
                    sb.append(s);
                } catch (BadHanyuPinyinOutputFormatCombination badHanyuPinyinOutputFormatCombination) {
                    badHanyuPinyinOutputFormatCombination.printStackTrace();
                }
            }
        }
        return sb.toString();
    }

}

String text = "特朗普";
String s = PinYinUtil.toPinYin(text);

demo： https://gitee.com/libraryDemo/PinYinDemo.git