JMH工具进行基准测试简单使用

来源：互联网发布：pcb电路板软件编辑：程序博客网时间：2024/05/29 17:02

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.jmh</groupId>            <artifactId>jmh-core</artifactId>            <version>1.9.3</version>        </dependency>        <dependency>            <groupId>org.openjdk.jmh</groupId>            <artifactId>jmh-generator-annprocess</artifactId>            <version>1.9.3</version>            <scope>provided</scope>        </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。

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