1. 使用pinyin4j

1.1 引入相关maven依赖

        <dependency>
            <groupId>com.belerweb</groupId>
            <artifactId>pinyin4j</artifactId>
            <version>2.5.0</version>
        </dependency>

1.2 汉字转换拼音工具类相关代码

import net.sourceforge.pinyin4j.PinyinHelper;
import net.sourceforge.pinyin4j.format.HanyuPinyinCaseType;
import net.sourceforge.pinyin4j.format.HanyuPinyinOutputFormat;
import net.sourceforge.pinyin4j.format.HanyuPinyinToneType;
import net.sourceforge.pinyin4j.format.HanyuPinyinVCharType;
import net.sourceforge.pinyin4j.format.exception.BadHanyuPinyinOutputFormatCombination;

/**
 * @description: 汉字拼音转换
 * @author: zyb
 * @date: 2020/01/13 15:40
 */
public class PinyinUtils {

    /**
     * 获得汉字拼音首字母
     * @param chines 中文
     * @return 汉字拼音首字母
     */
    public static String getAlpha(String chines) {
        String pinyinName = "";
        char[] nameChar = chines.toCharArray();
        HanyuPinyinOutputFormat defaultFormat = new HanyuPinyinOutputFormat();
        defaultFormat.setCaseType(HanyuPinyinCaseType.UPPERCASE);
        defaultFormat.setToneType(HanyuPinyinToneType.WITHOUT_TONE);
        for (int i = 0; i < nameChar.length; i++) {
            if (nameChar[i] > 128) {
                try {
                    pinyinName += PinyinHelper.toHanyuPinyinStringArray(
                            nameChar[i], defaultFormat)[0].charAt(0);
                } catch (BadHanyuPinyinOutputFormatCombination e) {
                    e.printStackTrace();
                }
            } else {
                pinyinName += nameChar[i];
            }
        }
        return pinyinName;
    }

    /**
     * 将字符串中的中文转化为拼音,英文字符不变
     * @param inputString 字符串
     * @return 全英文字符串
     */
    public static String getPingYin(String inputString) {
        HanyuPinyinOutputFormat format = new HanyuPinyinOutputFormat();
        format.setCaseType(HanyuPinyinCaseType.LOWERCASE);
        format.setToneType(HanyuPinyinToneType.WITHOUT_TONE);
        format.setVCharType(HanyuPinyinVCharType.WITH_V);
        String output = "";
        if (inputString != null && inputString.length() > 0
                && !"null".equals(inputString)) {
            char[] input = inputString.trim().toCharArray();
            try {
                for (int i = 0; i < input.length; i++) {
                    if (Character.toString(input[i]).matches(
                            "[\\u4E00-\\u9FA5]+")) {
                        String[] temp = PinyinHelper.toHanyuPinyinStringArray(
                                input[i], format);
                        output += temp[0];
                    } else
                        output += Character.toString(input[i]);
                }
            } catch (BadHanyuPinyinOutputFormatCombination e) {
                e.printStackTrace();
            }
        } else {
            return "*";
        }
        return output;
    }

    
    public static void main(String[] args) {
        String englishStr = PinyinUtils.getPingYin("测试123ceshi");
        String s = PinyinUtils.getAlpha("测试123ceshi");
        System.out.println(englishStr);
        System.out.println(s);
    }
}