Java 8 で導入された Base64 エンコーディング／デコーディングの機能と Commons Codec のそれとの性能比較をするプログラム。

Base64Performance.java

import org.apache.commons.math3.stat.descriptive.DescriptiveStatistics;

import java.util.Base64;
import java.util.function.Function;

/**
 * Java 8 と Commons Codec の Base64 エンコーディング・デコーディング性能を比較します。
 *
 * 比較対象の Commons Codec と、パフォーマンス測定結果の統計処理のために Commons Math3 が必要になります。
 */
public class Base64Performance {
    public static void main(String[] args) {
        measureAndShowPerformance(300000, 40, 20);
        measureAndShowPerformance(2000, 40, 20000);
    }

    static void measureAndShowPerformance(int loopTimes, int samplingTimes, int textLength) {
        double[] encodingPerformanceByJava8 =
                measureEncodingPerformance(
                        samplingTimes,
                        textLength,
                        data -> doEncodeByJava8(data, loopTimes));
        double[] encodingPerformanceByCommonsCodec =
                measureEncodingPerformance(
                        samplingTimes,
                        textLength,
                        data -> doEncodeByCommonsCodec(data, loopTimes));

        double[] decodingPerformanceByJava8 =
                measureDecodingPerformance(
                        samplingTimes,
                        textLength,
                        data -> doDecodeByJava8(data, loopTimes));
        double[] decodingPerformanceByCommonsCodec =
                measureDecodingPerformance(
                        samplingTimes,
                        textLength,
                        data -> doDecodeByCommonsCodec(data, loopTimes));

        System.out.printf("# loop:%d, sampling:%d, text length:%d", loopTimes, samplingTimes, textLength);
        System.out.println();

        showPerformance("Java8 Encoding", encodingPerformanceByJava8);
        showPerformance("Commons Codec Encoding", encodingPerformanceByCommonsCodec);

        showPerformance("Java8 Decoding", decodingPerformanceByJava8);
        showPerformance("Commons Codec Decoding", decodingPerformanceByCommonsCodec);
    }

    static void showPerformance(String label, double[] result) {
        DescriptiveStatistics stats = new DescriptiveStatistics(result);

        System.out.println("## " + label);
        System.out.println("* 1st quantile [ms] : " + stats.getPercentile(25));
        System.out.println("* median       [ms] : " + stats.getPercentile(50));
        System.out.println("* 3rd quantile [ms] : " + stats.getPercentile(75));
        System.out.println();
    }

    static double[] measureEncodingPerformance(int samplingTimes, int textLength, Function<byte[], Long> f) {
        double[] result = new double[samplingTimes];
        byte[] data = generateText(textLength).getBytes();

        for (int i = 0; i < samplingTimes; i++) {
            result[i] = f.apply(data);
        }

        return result;
    }

    static double[] measureDecodingPerformance(int samplingTimes, int textLength, Function<byte[], Long> f) {
        double[] result = new double[samplingTimes];
        byte[] data = Base64.getEncoder().encode(generateText(textLength).getBytes());

        for (int i = 0; i < samplingTimes; i++) {
            result[i] = f.apply(data);
        }

        return result;
    }

    static String generateText(int textLength) {

        String seed = "012ABCabcz";
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < (textLength + seed.length() - 1) / seed.length(); i++) {
            sb.append(seed);
        }

        return sb.toString()
                .substring(0, textLength);
    }

    // ----- Java 8 Standard Class Library

    static long doEncodeByJava8(byte[] data, int times) {
        Base64.Encoder encoder = Base64.getEncoder();
        long begin = System.currentTimeMillis();
        for (int i = 0; i < times; i++) {
            byte[] result = encoder.encode(data);
        }

        long end = System.currentTimeMillis();

        return end - begin;
    }

    static long doDecodeByJava8(byte[] data, int times) {
        Base64.Decoder decoder = Base64.getDecoder();
        long begin = System.currentTimeMillis();
        for (int i = 0; i < times; i++) {
            byte[] result = decoder.decode(data);
        }

        long end = System.currentTimeMillis();

        return end - begin;
    }

    // ----- Commons Codec

    static long doEncodeByCommonsCodec(byte[] data, int times) {
        long begin = System.currentTimeMillis();
        for (int i = 0; i < times; i++) {
            byte[] result = org.apache.commons.codec.binary.Base64.encodeBase64(data);
        }

        long end = System.currentTimeMillis();

        return end - begin;
    }

    static long doDecodeByCommonsCodec(byte[] data, int times) {
        long begin = System.currentTimeMillis();
        for (int i = 0; i < times; i++) {
            byte[] result = org.apache.commons.codec.binary.Base64.decodeBase64(data);
        }

        long end = System.currentTimeMillis();

        return end - begin;
    }
}