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利用btrace在線監控java程序狀態 ?

btrace介紹

????? 下載地址： https://kenai.com/projects/btrace/downloads/directory/releases/

????? 選擇版本進行下載，這里下載的是 release-1.2.4 / btrace-bin.zip

????? 這兩天在調試程序時，發現一個比較好用的工具-btrace，能夠線上監控程序狀態，獲取運行時數據信息，如方法返回值，參數，調用次數，全局變量，調用堆棧等。

btrace命令行使用

????? 位于bin目錄下面主要有6個腳本，3個windows的，另外3個是linux的，分別是btrace、btracec、btracer。具體功能如下：

????? 1、btrace

功能: 用于運行BTrace跟蹤程序。
命令格式:
???????? btrace [-I <include-path>] [-p <port>] [-cp <classpath>] <pid> <btrace-script> [<args>]
示例:
????????? btrace -cp build/? 1200 AllCalls1.java
參數含義:
??????? include-path指定頭文件的路徑，用于腳本預處理功能，可選；
??????? port指定BTrace agent的服務端監聽端口號，用來監聽clients，默認為2020，可選；
??????? classpath用來指定類加載路徑，默認為當前路徑，可選；?
????????pid表示進程號，可通過jps命令獲取；
??????? btrace-script即為BTrace腳本；btrace腳本如果以.java結尾，會先編譯再提交執行。可使用btracec命令對腳本進行預編譯。
?????? args是BTrace腳本可選參數，在腳本中可通過"$"和"$length"獲取參數信息。

???? 2. btracec

功能: 用于預編譯BTrace腳本，用于在編譯時期驗證腳本正確性。
??????? btracec [-I <include-path>] [-cp <classpath>] [-d <directory>] <one-or-more-BTrace-.java-files>
參數意義同btrace命令一致，directory表示編譯結果輸出目錄。

3. btracer?

功能: btracer命令同時啟動應用程序和BTrace腳本，即在應用程序啟動過程中使用BTrace腳本。而btrace命令針對已運行程序執行BTrace腳本。
命令格式:
?????? btracer <pre-compiled-btrace.class> <application-main-class> <application-args>
參數說明:
?????? pre-compiled-btrace.class表示經過btracec編譯后的BTrace腳本。
?????? application-main-class表示應用程序代碼；?
?????? application-args表示應用程序參數。?
?????? 該命令的等價寫法為:?
????????????? java -javaagent:btrace-agent.jar=script=<pre-compiled-btrace-script1>[,<pre-compiled-btrace-script1>]*??????? <MainClass> <AppArguments>

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btrace腳本限制

In particular, a BTrace class

• can not create new objects.
• can not create new arrays.
• can not throw exceptions.
• can not catch exceptions.
• can not make arbitrary instance or static method calls - only the public static methods of com.sun.btrace.BTraceUtils class may be called from a BTrace program.
• can not assign to static or instance fields of target program's classes and objects. But, BTrace class can assign to it's own static fields ("trace state" can be mutated).
• can not have instance fields and methods. Only static public void returning methods are allowed for a BTrace class. And all fields have to be static.
• can not have outer, inner, nested or local classes.
• can not have synchronized blocks or synchronized methods.
• can not have loops ( for, while, do..while)
• can not extend arbitrary class (super class has to be java.lang.Object)
• can not implement interfaces.
• can not contains assert statements.
• can not use class literals.

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jvisualvm 插件

BTrace提供了jvisualvm插件，強烈推薦在jvisualvm中編寫和測試BTrace腳本，啟動、關閉、發送事件、增加classpath都非常方便。

btrace實例

package baby.btrace;public class CaseObject{private static int sleepTotalTime=0; private int sleepTotalTime2=0; public boolean execute(int sleepTime) throws Exception{System.out.println("sleep: "+sleepTime);sleepTotalTime+=sleepTime;sleepTotalTime2=sleepTotalTime+1;sleep(sleepTime);if(sleepTime%2==0)return true;else return false;}public void sleep(int sleepTime) throws Exception { Thread.sleep(sleepTime); }}

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package baby.btrace;import java.util.Random;public class CaseObjectMain {int times = 10;public static void main(String[] args) {CaseObjectMain main= new CaseObjectMain();try {main.begin();} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}}public void begin() throws Exception{CaseObject object=new CaseObject();while(true){times++;boolean result=doWork(object);Thread.sleep(1000);}}public boolean doWork(CaseObject object) throws Exception{Random random=new Random();boolean temp= object.execute(random.nextInt(1000));return temp;}}

1、獲取返回值，參數等信息

/* BTrace Script Template */ import com.sun.btrace.annotations.*; import static com.sun.btrace.BTraceUtils.*;@BTrace public class TracingScript {/* put your code here */ /*指明要查看的方法，類*/@OnMethod(clazz="baby.btrace.CaseObject",method="execute",location=@Location(Kind.RETURN)) /*主要兩個參數是對象自己的引用 和 返回值，其它參數都是方法調用時傳入的參數*/public static void traceExecute(@Self baby.btrace.CaseObject object,int sleepTime, @Return boolean result){println("調用堆棧！！");println(strcat("返回結果是：",str(result)));jstack();println(strcat("時間是：",str(sleepTime)));}}

2、獲取對象屬性值

/* BTrace Script Template */ import com.sun.btrace.annotations.*; import static com.sun.btrace.BTraceUtils.*;@BTrace public class TracingScript {/* put your code here */ /*指明要查看的方法，類*/@OnMethod(clazz="baby.btrace.CaseObject",method="execute",location=@Location(Kind.RETURN)) /*主要兩個參數是對象自己的引用 和 返回值，其它參數都是方法調用時傳入的參數*/public static void traceExecute(@Self baby.btrace.CaseObject object,int sleepTime, @Return boolean result){println("調用堆棧！！");println(strcat("返回結果是：",str(result)));jstack();println(strcat("時間是：",str(sleepTime)));}}

3、獲取方法執行時長

import com.sun.btrace.annotations.*; import static com.sun.btrace.BTraceUtils.*;@BTrace public class TracingScript3 {@TLS private static long startTime = 0;@OnMethod(clazz="baby.btrace.CaseObject",method="execute") public static void startExecute(){startTime = timeNanos();} @OnMethod(clazz="baby.btrace.CaseObject",method="execute",location=@Location(Kind.RETURN)) public static void endExecute(@Duration long duration){long time = timeNanos() - startTime;println(strcat("execute time(nanos): ", str(time)));println(strcat("duration(nanos): ", str(duration)));} }

4、正則匹配和獲取方法執行次數

import com.sun.btrace.annotations.*; import static com.sun.btrace.BTraceUtils.*;@BTrace public class TracingScript4 {private static long count; @OnMethod(clazz="/.*/",method="execute",location=@Location(value=Kind.CALL, clazz="/.*/", method="sleep"))public static void traceExecute(@ProbeClassName String pcm, @ProbeMethodName String pmn,@TargetInstance Object instance, @TargetMethodOrField String method){println("====== ");println(strcat("ProbeClassName: ",pcm));println(strcat("ProbeMethodName: ",pmn));println(strcat("TargetInstance: ",str(classOf(instance))));println(strcat("TargetMethodOrField : ",str(method)));count++;}@OnEventpublic static void getCount(){println(strcat("count: ", str(count)));} }

5、正則和事件交互

import com.sun.btrace.annotations.*; import static com.sun.btrace.BTraceUtils.*;@BTrace public class TracingScript5 {private static long count; @OnMethod(clazz="/.*/",method="execute",location=@Location(value=Kind.CALL, clazz="/.*/", method="sleep"))public static void traceExecute(@ProbeClassName String pcm, @ProbeMethodName String pmn,@TargetInstance Object instance, @TargetMethodOrField String method){println("====== ");println(strcat("ProbeClassName: ",pcm));println(strcat("ProbeMethodName: ",pmn));println(strcat("TargetInstance: ",str(classOf(instance))));println(strcat("TargetMethodOrField : ",str(method)));count++;}@OnEventpublic static void getCount(){println(strcat("count: ", str(count)));}@OnEvent("A")public static void getCountA(){println("==AAAA==== ");println(strcat("count: ", str(count)));}@OnEvent("B")public static void getCountB(){println("==BBB==== ");println(strcat("count: ", str(count)));} }

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鏈接：

http://agapple.iteye.com/blog/1005918

http://agapple.iteye.com/blog/962119

轉載于:https://my.oschina.net/xiaominmin/blog/1599642

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