一种使用字节码增强技术检测线程阻塞的实现方式

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ScheduledThreadPoolExecutor;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;

public class BlockedThreadChecker {
    protected final static Log logger = LogFactory.getLog(BlockedThreadChecker.class);
    private static volatile BlockedThreadChecker instance;
    private final static int DELAY = 10;
    private final static int PERIOD = 1000;
    private ScheduledThreadPoolExecutor executor;
    private final Map<Thread, Task> threads = new ConcurrentHashMap<>();
    private BlockedThreadChecker(){
        logger.info("init BlockedThreadChecker... ...classloader:" + this.getClass().getClassLoader() + ",parent classloader:" + this.getClass().getClassLoader().getParent());
        int coreSize = Runtime.getRuntime().availableProcessors();
        ThreadFactory threadFactory = new ThreadFactory() {
            final AtomicInteger counter = new AtomicInteger();
            @Override
            public Thread newThread(Runnable r){
                Thread thread = new Thread(r, "BlockThreadCheckerTimer-" + counter.incrementAndGet());
                thread.setDaemon(true);
                return thread;
            }
        };

        executor = new ScheduledThreadPoolExecutor(coreSize, threadFactory);
        executor.scheduleAtFixedRate(new Runnable() {
            @Override
            public void run(){
                long now = System.currentTimeMillis();
                for(Map.Entry<Thread,Task> entry : threads.entrySet()){
                    long execStart = entry.getValue().startTime;
                    long dur = now - execStart;
                    if(dur >= entry.getValue().maxExecTime){
                        BlockedThreadException e = new BlockedThreadException(entry.getKey().getName() + " has been blocked " + dur + " ms");
                        e.setStackTrace(entry.getKey().getStackTrace());
                        logger.error(e.getMessage(),e);
                    }
                }
            }
        },DELAY,PERIOD, TimeUnit.MILLISECONDS);
    }
    public static BlockedThreadChecker getInstance(){
        if(instance != null){
            return instance;
        }

        synchronized (BlockedThreadChecker.class){
            if(instance != null){
                return instance;
            }
            instance = new BlockedThreadChecker();
        }
        return instance;
    }
    public void registerThread(Thread thread){
        registerThread(thread, new Task());
    }
    public void registerThread(Thread thread,Task task){
        threads.put(thread, task);
        logger.info("registerThread " + thread.getName());
    }
    public void unregisterThread(Thread thread){
        threads.remove(thread);
        logger.info("unregisterThread " + thread.getName());
    }
    class Task {
        long startTime = System.currentTimeMillis();
        long maxExecTime = 10000L;
    }
}

import com.alibaba.jvm.sandbox.api.Information;
import com.alibaba.jvm.sandbox.api.LoadCompleted;
import com.alibaba.jvm.sandbox.api.Module;
import com.alibaba.jvm.sandbox.api.listener.ext.Advice;
import com.alibaba.jvm.sandbox.api.listener.ext.AdviceListener;
import com.alibaba.jvm.sandbox.api.listener.ext.EventWatchBuilder;
import com.alibaba.jvm.sandbox.api.resource.ModuleEventWatcher;
import org.kohsuke.MetaInfServices;
import sun.misc.Unsafe;

import javax.annotation.Resource;
import java.lang.reflect.Field;
import java.util.Properties;

@MetaInfServices(Module.class)
@Information(id = "blocked-thread-module", version = "0.0.1", author = "yuji")
public class BlockedThreadModule implements Module, LoadCompleted {
    @Resource
    private ModuleEventWatcher moduleEventWatcher;
    private AdviceListener adviceListener = new AdviceListener() {
        @Override
        protected void before(Advice advice) throws Throwable {
            if (!advice.isProcessTop()) {
                return;
            }
            BlockedThreadChecker.getInstance().registerThread(Thread.currentThread());
        }
        @Override
        protected void afterReturning(Advice advice){
            if (!advice.isProcessTop()) {
                return;
            }
            BlockedThreadChecker.getInstance().unregisterThread(Thread.currentThread());
        }
        @Override
        protected void afterThrowing(Advice advice){
            if (!advice.isProcessTop()) {
                return;
            }
            BlockedThreadChecker.getInstance().unregisterThread(Thread.currentThread());
        }
    };
    @Override
    public void loadCompleted(){
        new EventWatchBuilder(moduleEventWatcher)
                .onClass("javax.servlet.http.HttpServlet")
                .onBehavior("service")
                .onWatch(adviceListener);

        new EventWatchBuilder(moduleEventWatcher)
                .onClass("com.alibaba.rocketmq.client.consumer.listener.MessageListenerConcurrently")
                .includeSubClasses()
                .onBehavior("consumeMessage")
                .onWatch(adviceListener);

        new EventWatchBuilder(moduleEventWatcher)
                .onClass("com.alibaba.rocketmq.client.consumer.listener.MessageListenerOrderly")
                .includeSubClasses()
                .onBehavior("consumeMessage")
                .onWatch(adviceListener);

        new EventWatchBuilder(moduleEventWatcher)
                .onClass("com.taobao.hsf.remoting.provider.ReflectInvocationHandler")
                .includeSubClasses()
                .onBehavior("invoke")
                .onWatch(adviceListener);
    }
}

//通过ByteBuddyAgent获取Instrumentation
Instrumentation inst = ByteBuddyAgent.install();

//将相应版本的sandbox-spy.jar添加到BootstrapClassLoader搜索路径中
//这一步的操作是由于sandbox-spy中包名是以java开头的，所以只能通过BootstrapClassLoader进行加载
JarFile spyJarFile = new JarFile("/目录/sandbox-spy-version.jar");
inst.appendToBootstrapClassLoaderSearch(spyJarFile);
//构造jvm-sandbox CoreFeatureString
String sandboxCoreFeatureString = String.format(";system_module=%s;mode=%s;sandbox_home=%s;provider=%s;namespace=%s;unsafe.enable=true;",systemModule, "agent", sandboxHome, provider, NAMESPACE );
CoreConfigure coreConfigure = CoreConfigure.toConfigure(sandboxCoreFeatureString,null);
CoreLoadedClassDataSource classDataSource = new DefaultCoreLoadedClassDataSource(inst,true);
ProviderManager providerManager = new DefaultProviderManager(coreConfigure);
//核心类，用户自定义的module是在这个类中完成加载和初始化的
CoreModuleManager coreModuleManager = new DefaultCoreModuleManager(coreConfigure,inst,classDataSource,providerManager);
//初始化命名空间与SpyHandler对于关系
SpyUtils.init(NAMESPACE);
//加载各种module
coreModuleManager.reset();