JMH工具进行基准测试简单使用

参考资料：
http://www.importnew.com/12548.html
http://blog.csdn.net/hfmbook/article/details/70209150
依赖库:

<dependency>
            <groupId>org.openjdk.jmhgroupId>
            <artifactId>jmh-coreartifactId>
            <version>1.9.3version>
        dependency>
        <dependency>
            <groupId>org.openjdk.jmhgroupId>
            <artifactId>jmh-generator-annprocessartifactId>
            <version>1.9.3version>
            <scope>providedscope>
        dependency>

Main方法:

import com.nxg.JmhDemo;
import org.openjdk.jmh.runner.Runner;
import org.openjdk.jmh.runner.options.Options;
import org.openjdk.jmh.runner.options.OptionsBuilder;



public class MyPro {

    public static void main(String [] args) throws Exception{
        Options opt = new OptionsBuilder()
                .include(JmhDemo.class.getSimpleName())
                .forks(1)
                .warmupIterations(5) //预热次数
                .measurementIterations(5) //真正执行次数
                .build();

        new Runner(opt).run();
    }

}

测试类:

package com.nxg;

import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.BenchmarkMode;
import org.openjdk.jmh.annotations.Mode;
import org.openjdk.jmh.annotations.OutputTimeUnit;

import java.util.concurrent.TimeUnit;

public class JmhDemo {

    @Benchmark
    @BenchmarkMode(Mode.Throughput)
    @OutputTimeUnit(TimeUnit.SECONDS)
    public void stringLoop(){
        String str = new String();
        for(int i = 0; i<100; i++){
            str += "str\t";
            str += "str\t";
            str += "str\t";
            str += "str\t";
            str += "str\t";
        }


    }

    @Benchmark
    @BenchmarkMode(Mode.Throughput)
    @OutputTimeUnit(TimeUnit.SECONDS)
    public void builderLoop(){
        StringBuilder builder = new StringBuilder();
        for(int i = 0; i<100; i++){
            builder.append("str\t");
            builder.append("str\t");
            builder.append("str\t");
            builder.append("str\t");
            builder.append("str\t");
        }


    }

    @Benchmark
    @BenchmarkMode(Mode.Throughput)
    @OutputTimeUnit(TimeUnit.SECONDS)
    public void bufferLoop(){
        StringBuffer buffer = new StringBuffer();
        for(int i = 0; i < 100; i++){
            buffer.append("str\t");
            buffer.append("str\t");
            buffer.append("str\t");
            buffer.append("str\t");
            buffer.append("str\t");
        }
    }
}

总结:基本上我们的代码都可以这么测试一下，尤其是需要对一些库进行选择的时候，非常好用。