====MimeUtilityを利用====
[[Java]]{{category コード片}}
<<blockquote>>Java8から標準ライブラリに含まれた<</blockquote>>
*http://java.sun.com/j2ee/1.4/docs/api/javax/mail/internet/MimeUtility.html
StringBuilder sourceBuf = new StringBuilder(StringUtils.defaultString(source));
int fillCnt = (sourceBuf.toString().length() % 4);
for (int i = 0; i < < fillCnt; i++) {
sourceBuf.append(" ");
}