Java運行時間測量：JETM

 

戈思漢 高波

 

Java運行時間測量：JETM

JETM是一個Java程序執行時間測量工具。幫助開發人員定位Java程序中的性能問題。

http://jetm.void.fm/

該jetm是一個免費的jar包，能夠放入其餘項目中調用api來使用

一般咱們本身調試經過System.currentTimeMillis()打出程序段執行的時間，而如今

直接借用jetm就能像log4j 那樣隨意設置程序段執行時間。

 

簡單地嵌入代碼中：

public class BusinessService {

private static final EtmMonitor

etmMonitor = EtmManager.getEtmMonitor();

public void someMethod() {

           EtmPoint point = etmMonitor.createPoint("BusinessService:someMethod");

           try {

             //

             // some business code

             //

             nestedMethod();

           } finally {

             point.collect();

           }

        }

  public void nestedMethod() {

  EtmPoint point = etmMonitor.createPoint("BusinessService:nestedMethod");

           try {

             // some business code

           } finally {

             point.collect();

           }

        }

    }

 

上面的簡單模式是要直接嵌入到目的代碼中，若是引用AOP的思路，就只要經過配置實現嵌入動做。

好比，和spring集成，自己spring就是依據AOP思路開發的框架。

下面以spring 2.x爲例，須要在spring的配置文件中添加jetm namespace和 jetm:runtime tag

下面爲整個spring的配置文。

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"

       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

       xmlns:jetm="http://jetm.void.fm/schema/jetm_spring_config_1_2"

       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd

                           http://jetm.void.fm/schema/jetm_spring_config_1_2 http://jetm.void.fm/schema/jetm_spring_config_1_2.xsd ">

 

 <bean id="orderClient"

        class="etm.tutorial.fiveminute.client.OrderClient"

        autowire="constructor"/>

 

 <bean id="groceryStore"

        class="etm.tutorial.fiveminute.store.GroceryStoreImpl"

        autowire="constructor"/>

 

 <bean id="stockDao" class="etm.tutorial.fiveminute.store.dao.StockDaoImpl"

        autowire="constructor"/>

 

 <!-- Step 4: Add performance monitoring -->

 <!--

    <jetm:monitoring>

      <jetm:bean-pattern>*Dao</jetm:bean-pattern>

      <jetm:bean-pattern>groceryStore</jetm:bean-pattern>

    </jetm:monitoring>

 -->

 

 <!-- Step 5: Enable HTTP console -->

 <!--

    <jetm:console expanded="true"/>

 -->

 

 <jetm:runtime>

    <jetm:features>

 

      <!-- Step 6: Alter aggregation chain -->

      <!--

        <jetm:interval-buffer interval="1000"/>

      -->

 

      <!-- Step 7: Log raw performance results -->

      <!--

        <jetm:raw-data-log type="commons"/>

      -->

 

    </jetm:features>

 </jetm:runtime>

 

</beans>

 

另外集成aop框架AspectWerkz

Aop.xml爲

<!DOCTYPE aspectwerkz PUBLIC "-//AspectWerkz//DTD 2.0//EN"

  "http://aspectwerkz.codehaus.org/dtd/aspectwerkz2.dtd">

 

<aspectwerkz>

 <system id="weaving-example">

 

    <aspect class="etm.contrib.aop.aspectwerkz.EtmAspectWerkzAspect"

            deployment-model="perJVM">

 

      <pointcut name="etmExample" expression="

          execution(public * etm.samples.aop.aspectwerkz.*Service.*(..))

          OR

          execution(public * etm.samples.aop.aspectwerkz.Dao+.*(..))

      "/>

 

      <advice name="monitor" type="around" bind-to="etmExample"/>

 

    </aspect>

 

 </system>

</aspectwerkz>