Btrace 拦截时机

2023-08-10 10:11:04

Kind.ENTRY 入口，默认值

Kind.RETURN: 返回

Kind.THROW: 异常

Kind.Line: 行

一、返回时拦截

package com.example.monitor_tuning.chapter4;

import com.sun.btrace.AnyType;

import com.sun.btrace.BTraceUtils;

import com.sun.btrace.annotations.*;

@BTrace

public class PrintReturn {

    @OnMethod(

            clazz = "com.example.monitor_tuning.chapter4.Ch4Controller",

            method="arg1",

            location = @Location(Kind.RETURN)

    )

    public static  void anyRead(@ProbeClassName String pcn, @ProbeMethodName String  pmn, @Return AnyType result)

    {

        BTraceUtils.println(pcn + "," + pmn + "," + result);

        BTraceUtils.println();

    }

}

2、运行和返回结果

1）、运行

2）、调用接口：

http://127.0.0.1:8080/monitor_tuning/ch4/arg1?name=nick

3）返回结果见上图

二、异常时拦截

1、创建异常代码

2、创建异常脚本

package com.example.monitor_tuning.chapter4;

import com.sun.btrace.BTraceUtils;

import com.sun.btrace.annotations.*;

/**

 * 拦截异常

 */

@BTrace

public class PrintOnThrow {

    @TLS

    static Throwable currentException;

    @OnMethod(

            clazz = "java.lang.Throwable",

            method="<init>"

    )

    //拦截 new Throwable

    public static  void onthrow(@Self Throwable self)

    {

       currentException = self;

    }

    @OnMethod(

            clazz = "java.lang.Throwable",

            method="<init>"

    )

    //拦截 new Throwable(String msg)

    public static  void onthrow1(@Self Throwable self, String s)

    {

        currentException = self;

    }

    @OnMethod(

            clazz = "java.lang.Throwable",

            method="<init>"

    )

    //拦截 new Throwable(Throwable self, String s, Throwable cause)

    public static  void onthrow1(@Self Throwable self, String s, Throwable cause)

    {

        currentException = self;

    }

    @OnMethod(

            clazz = "java.lang.Throwable",

            method="<init>"

    )

    //拦截 new Throwable( Throwable self,  Throwable cause)

    public static  void onthrow2(@Self Throwable self,  Throwable cause)

    {

        currentException = self;

    }

    @OnMethod(

            clazz = "java.lang.Throwable",

            method="<init>",

            location = @Location(Kind.RETURN)

    )

    public static  void onthrowreturn()

    {

        if(currentException != null){

            BTraceUtils.Threads.jstack(currentException); //打印异常堆栈

            BTraceUtils.println("==============");

            currentException = null;

        }

    }

}

3、运行btrace脚本

调用接口

http://127.0.0.1:8080/monitor_tuning/ch4/exception

显示结果

三、打印行号

1、打印36行是否执行

2、创建btrace脚本

package com.example.monitor_tuning.chapter4;

import com.sun.btrace.BTraceUtils;

import com.sun.btrace.annotations.*;

/**

 * 打印行号，查看指定行号是否执行到

 */

@BTrace

public class PrintLine {

    @OnMethod(

            clazz = "com.example.monitor_tuning.chapter4.Ch4Controller",

            location = @Location(value = Kind.LINE, line = 36)

    )

    public static  void anyRead(@ProbeClassName String pcn, @ProbeMethodName String  pmn, int line)

    {

        BTraceUtils.println(pcn + "," + pmn + ", " + line);

        BTraceUtils.println();

    }

}