使用byte-buddy的java级别的工具

Question

我有一个Thread Pool示例代码如下

public class RunThreads{
static final int MAX_TASK = 3;

public static void main(String[] args)
{
    Runnable r1 = new Task("task 1");
    Runnable r2 = new Task("task 2");
    Runnable r3 = new Task("task 3");
    Runnable r4 = new Task("task 4");
    Runnable r5 = new Task("task 5");

    ExecutorService pool = Executors.newFixedThreadPool(MAX_TASK);

    pool.execute(r1);
    pool.execute(r2);
    pool.execute(r3);
    pool.execute(r4);
    pool.execute(r5);
    pool.shutdown();
}}

和

class Task implements Runnable{
private String name;

public Task(String s)
{
    name = s;
}
public void run()
{
    try
    {
        for (int i = 0; i<=5; i++)
        {
            if (i==0)
            {
                Date d = new Date();
                SimpleDateFormat ft = new SimpleDateFormat("hh:mm:ss");
                System.out.println("Initialization Time for"
                        + " task name - "+ name +" = " +ft.format(d));
                //prints the initialization time for every task
            }
            else
            {
                Date d = new Date();
                SimpleDateFormat ft = new SimpleDateFormat("hh:mm:ss");
                System.out.println("Executing Time for task name - "+
                        name +" = " +ft.format(d));
                // prints the execution time for every task
            }
            Thread.sleep(1000);
        }
        System.out.println(name+" complete");
    }

    catch(InterruptedException e)
    {
        e.printStackTrace();
    }
}}

我为仪器java ThreadPoolExecutor创建了一个小代理，如下所示

public class Agent {

public static void premain(String arguments, Instrumentation instrumentation) {

    new AgentBuilder.Default()
            .with(new AgentBuilder.InitializationStrategy.SelfInjection.Eager())
            .type((ElementMatchers.nameContains("ThreadPoolExecutor")))
            .transform(
                    new AgentBuilder.Transformer.ForAdvice()
                            .include(MonitorInterceptor.class.getClassLoader())
                            .advice(ElementMatchers.any(), MonitorInterceptor.class.getName())
            ).installOn(instrumentation);
}}

我们可以使用Byte Buddy来设置类似ThreadPoolExecutor的java类。当我调试ThreadPoolExecutor类工作。但当我尝试使用代理ThreadPoolExecutor类永远不会工作。

编辑这是我的MonitorInterceptor

public class MonitorInterceptor {


@Advice.OnMethodEnter
static void enter(@Advice.Origin String method) throws Exception {

    System.out.println(method);

}

编辑

new AgentBuilder.Default()
            .with(new AgentBuilder.InitializationStrategy.SelfInjection.Eager())
            .with(AgentBuilder.Listener.StreamWriting.toSystemError())
            .ignore(none())
            .type((ElementMatchers.nameContains("ThreadPoolExecutor")))
            .transform((builder, typeDescription, classLoader, module) -> builder
                    .constructor(ElementMatchers.any())
                    .intercept(Advice.to(MyAdvice.class))
                    .method(ElementMatchers.any())
                    .intercept(Advice.to(MonitorInterceptor.class))
            ).installOn(instrumentation);

Answer 1

除非您明确配置它，否则Byte Buddy不会使用核心Java类。您可以通过显式设置不排除此类的忽略匹配器来更改它。

在此上下文中，使用Advice时不必配置初始化策略。

您可能还想限制建议的范围，现在您可以拦截任何方法或构造函数。

要找出问题所在，您还可以定义AgentBuilder.Listener以通知错误。

Answer 2

使用Rafael Winterhalter回答我解决了这个问题。我按如下方式创建代理，

new AgentBuilder.Default()
                .ignore(ElementMatchers.none())
                .type(ElementMatchers.nameContains("ThreadPoolExecutor"))
                .transform((builder, type, classLoader, module) -> builder
                        .visit(Advice.to(ThreadPoolExecutorAdvice.class).on(ElementMatchers.any()))
                ).installOn(instrumentation); 

使用这个，我们可以使用Java class.Form这个构造函数给出这样的

java.util.concurrent.ThreadPoolExecutor$Worker(java.util.concurrent.ThreadPoolExecutor,java.lang.Runnable)

但是在代码构造函数中，不是那样的，它是

public ThreadPoolExecutor(int corePoolSize,
                              int maximumPoolSize,
                              long keepAliveTime,
                              TimeUnit unit,
                              BlockingQueue<Runnable> workQueue) {
        this(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue,
             Executors.defaultThreadFactory(), defaultHandler);
    }

所以我期待类似的东西

java.util.concurrent.ThreadPoolExecutor(int,int,long,java.util.concurrent.TimeUnit,java.util.concurrent.BlockingQueue)

我使用javassist来获取构造函数，并将其作为byte-buddy给出的内容。因此，使用.ignore(ElementMatchers.none())和visit(Advice.to(ThreadPoolExecutorAdvice.class).on(ElementMatchers.any()))we可以获得Java级别的所有构造函数和方法