废话不多说直接上源码
依赖jar包:

        <dependency>
            <groupId>com.github.obiteaaron</groupId>
            <artifactId>pinyin4j-multi</artifactId>
            <version>1.0.0</version>
        </dependency>
package com.jctl.cloud.utils;
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;
/** * Created by gent on 2017/3/31. */
public class ChineseToPinyin {
    // 将汉字转换为全拼
    public static String getPingYin(String src) {

        char[] t1 = null;
        t1 = src.toCharArray();
        String[] t2 = new String[t1.length];
        HanyuPinyinOutputFormat t3 = new HanyuPinyinOutputFormat();

        t3.setCaseType(HanyuPinyinCaseType.LOWERCASE);
        t3.setToneType(HanyuPinyinToneType.WITHOUT_TONE);
        t3.setVCharType(HanyuPinyinVCharType.WITH_V);
        String t4 = "";
        int t0 = t1.length;
        try {
            for (int i = 0; i < t0; i++) {
                // 判断是否为汉字字符
                if (Character.toString(t1[i]).matches(
                        "[\\u4E00-\\u9FA5]+")) {
                    t2 = PinyinHelper.toHanyuPinyinStringArray(t1[i], t3);
                    t4 += t2[0];
                } else
                    t4 += Character.toString(t1[i]);
            }
            // System.out.println(t4);
            return t4;
        } catch (BadHanyuPinyinOutputFormatCombination e1) {
            e1.printStackTrace();
        }
        return t4;
    }

    // 返回中文的首字母
    public static String getPinYinHeadChar(String str) {

        String convert = "";
        for (int j = 0; j < str.length(); j++) {
            char word = str.charAt(j);
            String[] pinyinArray = PinyinHelper.toHanyuPinyinStringArray(word);
            if (pinyinArray != null) {
                convert += pinyinArray[0].charAt(0);
            } else {
                convert += word;
            }
        }
        return convert;
    }

    // 将字符串转移为ASCII码
    public static String getCnASCII(String cnStr) {
        StringBuffer strBuf = new StringBuffer();
        byte[] bGBK = cnStr.getBytes();
        for (int i = 0; i < bGBK.length; i++) {
            strBuf.append(Integer.toHexString(bGBK[i] & 0xff));
        }
        return strBuf.toString();
    }

    public static void main(String[] args) {
        System.out.println(getPingYin("北京"));

    }
}
04-19 18:42