汉字转换为拼音

public static String chineseToPinyin(String str){
        HanyuPinyinOutputFormat format = new HanyuPinyinOutputFormat();
        format.setVCharType(HanyuPinyinVCharType.WITH_V);
        format.setToneType(HanyuPinyinToneType.WITHOUT_TONE);
        format.setCaseType(HanyuPinyinCaseType.LOWERCASE);
        
        StringBuilder result = new StringBuilder();
        for (int i = 0; i < str.length(); i++) {
            char ch = str.charAt(i);
            String[] pinyins;
            try {
                pinyins = PinyinHelper.toHanyuPinyinStringArray(ch,format);
                if (pinyins != null){
                    result.append(pinyins[0]);
                } else {
                    result.append(ch);
                }
            } catch (BadHanyuPinyinOutputFormatCombination e) {
                e.printStackTrace();
            }
        }
        return result.toString();
    }