BTrace

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package com.test;

public class OrderProcessor {
    public void processOrder(int quantity, double unitPrice) {
        double discount = 0.1;
        double totalPrice = (quantity * unitPrice) - (quantity * unitPrice * discount);
        System.out.println("Total price after discount: " + totalPrice);
    }

    public static void main(String[] args) throws InterruptedException {
        OrderProcessor processor = new OrderProcessor();
        while (true) {
            processor.processOrder(5, 20.0);  // Simulate order processing
            Thread.sleep(5000); // Simulate delay between processing
        }
    }
}

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import org.openjdk.btrace.core.annotations.*;
import static org.openjdk.btrace.core.BTraceUtils.*;

@BTrace
public class TraceLocalVariables {

	@OnMethod(
		clazz = "com.test.OrderProcessor",
		method = "processOrder"
	)
	public static void traceVariables(int quantity, double unitPrice) {
		println("Method processOrder is called with parameters:");
		println("quantity: " + quantity);
		println("unitPrice: " + unitPrice);
		jstack();
	}
}

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btrace.bat 92712 .\TraceLocalVariables.java

[main] INFO org.openjdk.btrace.client.Main - Attaching BTrace to PID: 92712
[main] INFO org.openjdk.btrace.client.Client - Successfully started BTrace probe: .\TraceLocalVariables.java
Method processOrder is called with parameters:

quantity: 5

unitPrice: 20.0

com.test.OrderProcessor.processOrder(OrderProcessor.java)
com.test.OrderProcessor.main(OrderProcessor.java:13)

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    public void processOrder(int quantity, double unitPrice) {
        double discount = 0.1;
        double totalPrice = (quantity * unitPrice) - (quantity * unitPrice * discount);
        //System.out.println("Total price after discount: " + totalPrice);
		System.out.println("haha -> " + discount + "," + totalPrice);
    }

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retransform /data/test/OrderProcessor.class

retransform -l
Id              ClassName       TransformCount  LoaderHash      LoaderClassName
3               com.test.OrderP 1               null            null
                rocessor

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Total price after discount: 90.0
Total price after discount: 90.0
haha -> 0.1,90.0
haha -> 0.1,90.0

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javac -d . -g .\OrderProcessor.java

java -agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=5005 -cp . com.test.OrderProcessor

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jdb -connect com.sun.jdi.SocketAttach:hostname=[your ip],port=5005
设置未捕获的java.lang.Throwable
设置延迟的未捕获的java.lang.Throwable
正在初始化jdb...
> threads
组system:
  (java.lang.ref.Reference$ReferenceHandler)0x1b5 Reference Handler正在执行条件等待
  (java.lang.ref.Finalizer$FinalizerThread)0x1b6  Finalizer        正在执行条件等待
  (java.lang.Thread)0x1b7                         Signal Dispatcher正在运行
  (java.lang.Thread)0x1b8                         Attach Listener  正在运行
组main:
  (java.lang.Thread)0x1                           main             正在休眠

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> stop at com.test.OrderProcessor:8
设置断点com.test.OrderProcessor:8
>
断点命中: "线程=main", com.test.OrderProcessor.processOrder(), 行=8 bci=19

main[1] locals
方法参数:
quantity = 5
unitPrice = 20.0
本地变量:
discount = 0.1
totalPrice = 90.0
main[1]