分转元并去掉小数点后面无用值
public static String convertFen2Yuan(String fen) {
    BigDecimal fenAmt = new BigDecimal(fen);
    BigDecimal yuanAmt = fenAmt.divide(new BigDecimal(100)).setScale(2, RoundingMode.DOWN).stripTrailingZeros();
    return yuanAmt.toString();
}

测试：

如果不论小数点后面数字为多少，都保留两位的话则吧.stripTrailingZeros()方法去掉

public static String convertFen2Yuan(String fen) {
    BigDecimal fenAmt = new BigDecimal(fen);
    BigDecimal yuanAmt = fenAmt.divide(new BigDecimal(100)).setScale(2, RoundingMode.DOWN);
    return yuanAmt.toString();
}

测试：

如果转字符串的话，加.toPlainString()就行，比如 

new BigDecimal("95.000").stripTrailingZeros().toPlainString()