引入依赖

        <dependency>
            <groupId>com.belerweb</groupId>
            <artifactId>pinyin4j</artifactId>
            <version>2.5.1</version>
        </dependency>

工具类

import cn.hutool.extra.pinyin.PinyinUtil;

/**
 * 中文拼音转换工具
 * 
 * @author Lan Zhan
 */
public class PinYinUtil {

    public static String getFullPinyin(String text, boolean ignoreIfNotChinese) {
        String pinyin = PinyinUtil.getPinyin(text).toUpperCase();
        if (ignoreIfNotChinese) {
            return pinyin.replaceAll("[^A-Z]", "");
        } else {
            return pinyin;
        }
    }

    public static String getSimplePinyin(String text, boolean ignoreIfNotChinese) {
        String pinyin = PinyinUtil.getFirstLetter(text, "").toUpperCase();
        if (ignoreIfNotChinese) {
            return pinyin.replaceAll("[^A-Z]", "");
        } else {
            return pinyin;
        }
    }

}

示例

public static void main(String[] arg0) throws Exception {
        String pinyin = PinYinUtil.getFullPinyin("如果不出意外的话就没有意外出现");
        String fullPinyin= PinYinUtil.getFullPinyin("如果不出意外的话就没有意外出现");

        // 输出 ru guo bu chu yi wai de hua jiu mei you yi wai chu xian
        System.out.println(pinyin);

        // 输出 R G B C Y W D H J M Y Y W C X
        System.out.println(fullPinyin);
}