如果你希望用 JUnit 來測試一些性能問題，那么 JUnitBenchmark 可以幫到你，主要特性：
- 記錄執(zhí)行時間
- 監(jiān)控垃圾收集
- 測試熱身
package com.paul;
import com.carrotsearch.junitbenchmarks.AbstractBenchmark;
import com.carrotsearch.junitbenchmarks.BenchmarkOptions;
import javolution.text.TextBuilder;
import org.junit.Test;
/**
* Benchmark for String concatenation. Compares StringBUilder (JDK) and
* TextBuilder (Javolution).
*/
public class StringConcatenationBenchmark extends AbstractBenchmark {
public static final long LOOPS_COUNT = 10000000;
@Test
@BenchmarkOptions(benchmarkRounds = 3, warmupRounds = 1)
public void stringBuilderBenchmark() {
StringBuilder builder = new StringBuilder();
for (long i = 0; i < LOOPS_COUNT; i++) {
builder.append('i').append(i);
}
System.out.println(builder.toString().length());
}
@Test
@BenchmarkOptions(benchmarkRounds = 3, warmupRounds = 1)
public void textBuilderBenchmark() {
TextBuilder builder = new TextBuilder();
for (long i = 0; i < LOOPS_COUNT; i++) {
builder.append('i').append(i);
}
System.out.println(builder.toString().length());
}
}
Maven依賴：
<dependency>
<groupId>javolution</groupId>
<artifactId>javolution</artifactId>
<version>5.4.5</version>
</dependency>
結(jié)果顯示：
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StringConcatenationBenchmark.stringBuilderBenchmark: [measured 3 out of 4 rounds, threads: 1 (sequential)]
round: 0.57 [+- 0.01], round.gc: 0.00 [+- 0.00], GC.calls: 33, GC.time: 0.02, time.total: 2.60, time.warmup: 0.90, time.bench: 1.70
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StringConcatenationBenchmark.textBuilderBenchmark: [measured 3 out of 4 rounds, threads: 1 (sequential)]
round: 0.46 [+- 0.03], round.gc: 0.00 [+- 0.00], GC.calls: 14, GC.time: 0.14, time.total: 1.92, time.warmup: 0.55, time.bench: 1.38