说到我为什么要用动态线程池，有两点原因。一是踩坑了，有次进行了服务优化后低估了线上的流量，导致上了第一台机器后开始报接口超时的错误，发现是设置的线程池核心数量太小，以及队列长度过大，导致过多请求阻塞在任务队列里，没办法，只能修改参数再重新上一次。二是因为想将服务器资源利用率提升到最大化。其实动态线程池在美团已经用上了，只是他们的框架没有开源，没办法，只能自己实现一下。
具体为什么能实现可以参考下美团的这篇文章，说的很详细。https://tech.meituan.com/2020/04/02/java-pooling-pratice-in-meituan.html
如果你公司已经有分布式配置中心中间件的话，就可以直接用我这个代码，如果没有这个中间件的话，可以去Gitee或者Github参考开源框架Cubic或者Hippo，看哪个更适合你，话不多说，下面看代码。
1、自定义动态线程池
/**
* @Description 线程池
* @Date 2021/12/4 4:26 下午
* @Author chenzhibin
*/
public class DynamicThreadPoolExecutor extends ThreadPoolExecutor {
/**
* 线程池名称
*/
private String threadPoolName;
/**
* 任务名称
*/
private String defaultTaskName = "defaultTask";
/**
* 拒绝策略：默认直接抛出RejectedExecutionException异常
*/
private static final RejectedExecutionHandler defaultHandler = new AbortPolicy();
private Map runnableNameMap = new ConcurrentHashMap<>();
public DynamicThreadPoolExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, BlockingQueue workQueue) {
super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue);
}
public DynamicThreadPoolExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit,
BlockingQueue workQueue, ThreadFactory threadFactory) {
super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue, threadFactory, defaultHandler);
}
public DynamicThreadPoolExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit,
BlockingQueue workQueue, ThreadFactory threadFactory, RejectedExecutionHandler handler, String threadPoolName) {
super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue, threadFactory, handler);
this.threadPoolName = threadPoolName;
}
@Override
public void execute(Runnable command) {
runnableNameMap.putIfAbsent(command.getClass().getSimpleName(), defaultTaskName);
super.execute(command);
}
public void execute(Runnable command, String taskName) {
runnableNameMap.putIfAbsent(command.getClass().getSimpleName(), taskName);
super.execute(command);
}
public Future submit(Runnable task, String taskName) {
runnableNameMap.putIfAbsent(task.getClass().getSimpleName(), taskName);
return super.submit(task);
}
public Future submit(Callable task, String taskName) {
runnableNameMap.putIfAbsent(task.getClass().getSimpleName(), taskName);
return super.submit(task);
}
public Future submit(Runnable task, T result, String taskName) {
runnableNameMap.putIfAbsent(task.getClass().getSimpleName(), taskName);
return super.submit(task, result);
}
@Override
public Future submit(Runnable task) {
runnableNameMap.putIfAbsent(task.getClass().getSimpleName(), defaultTaskName);
return super.submit(task);
}
@Override
public Future submit(Callable task) {
runnableNameMap.putIfAbsent(task.getClass().getSimpleName(), defaultTaskName);
return super.submit(task);
}
@Override
public Future submit(Runnable task, T result) {
runnableNameMap.putIfAbsent(task.getClass().getSimpleName(), defaultTaskName);
return super.submit(task, result);
}
public String getThreadPoolName() {
return threadPoolName;
}
public void setThreadPoolName(String threadPoolName) {
this.threadPoolName = threadPoolName;
}
}
2、实现可重新设置大小的任务队列,其实就是让阻塞队列的capacity不被final修饰
/**
* @Description 可以重新设置队列大小的ResizableCapacityResizableCapacityLinkedBlockIngQueue
* @Date 2021/12/4 4:32 下午
* @Author chenzhibin
*/
public class ResizableCapacityLinkedBlockIngQueue extends AbstractQueue
implements BlockingQueue, java.io.Serializable {
private static final long serialVersionUID = -6903933977591709194L;
/*
* A variant of the "two lock queue" algorithm. The putLock gates
* entry to put (and offer), and has an associated condition for
* waiting puts. Similarly for the takeLock. The "count" field
* that they both rely on is maintained as an atomic to avoid
* needing to get both locks in most cases. Also, to minimize need
* for puts to get takeLock and vice-versa, cascading notifies are
* used. When a put notices that it has enabled at least one take,
* it signals taker. That taker in turn signals others if more
* items have been entered since the signal. And symmetrically for
* takes signalling puts. Operations such as remove(Object) and
* iterators acquire both locks.
*
* Visibility between writers and readers is provided as follows:
*
* Whenever an element is enqueued, the putLock is acquired and
* count updated. A subsequent reader guarantees visibility to the
* enqueued Node by either acquiring the putLock (via fullyLock)
* or by acquiring the takeLock, and then reading n = count.get();
* this gives visibility to the first n items.
*
* To implement weakly consistent iterators, it appears we need to
* keep all Nodes GC-reachable from a predecessor dequeued Node.
* That would cause two problems:
* - allow a rogue Iterator to cause unbounded memory retention
* - cause cross-generational linking of old Nodes to new Nodes if
* a Node was tenured while live, which generational GCs have a
* hard time dealing with, causing repeated major collections.
* However, only non-deleted Nodes need to be reachable from
* dequeued Nodes, and reachability does not necessarily have to
* be of the kind understood by the GC. We use the trick of
* linking a Node that has just been dequeued to itself. Such a
* self-link implicitly means to advance to head.next.
*/
/**
* Linked list node class
*/
static class Node {
E item;
/**
* One of:
* - the real successor Node
* - this Node, meaning the successor is head.next
* - null, meaning there is no successor (this is the last node)
*/
ResizableCapacityLinkedBlockIngQueue.Node next;
Node(E x) {
item = x;
}
}
/**
* The capacity bound, or Integer.MAX_VALUE if none
*/
private int capacity;
/**
* Current number of elements
*/
private final AtomicInteger count = new AtomicInteger();
/**
* Head of linked list.
* Invariant: head.item == null
*/
transient ResizableCapacityLinkedBlockIngQueue.Node head;
/**
* Tail of linked list.
* Invariant: last.next == null
*/
private transient ResizableCapacityLinkedBlockIngQueue.Node last;
/**
* Lock held by take, poll, etc
*/
private final ReentrantLock takeLock = new ReentrantLock();
/**
* Wait queue for waiting takes
*/
private final Condition notEmpty = takeLock.newCondition();
/**
* Lock held by put, offer, etc
*/
private final ReentrantLock putLock = new ReentrantLock();
/**
* Wait queue for waiting puts
*/
private final Condition notFull = putLock.newCondition();
/**
* Signals a waiting take. Called only from put/offer (which do not
* otherwise ordinarily lock takeLock.)
*/
private void signalNotEmpty() {
final ReentrantLock takeLock = this.takeLock;
takeLock.lock();
try {
notEmpty.signal();
} finally {
takeLock.unlock();
}
}
/**
* Signals a waiting put. Called only from take/poll.
*/
private void signalNotFull() {
final ReentrantLock putLock = this.putLock;
putLock.lock();
try {
notFull.signal();
} finally {
putLock.unlock();
}
}
/**
* Links node at end of queue.
*
* @param node the node
*/
private void enqueue(ResizableCapacityLinkedBlockIngQueue.Node node) {
// assert putLock.isHeldByCurrentThread();
// assert last.next == null;
last = last.next = node;
}
/**
* Removes a node from head of queue.
*
* @return the node
*/
private E dequeue() {
// assert takeLock.isHeldByCurrentThread();
// assert head.item == null;
ResizableCapacityLinkedBlockIngQueue.Node h = head;
ResizableCapacityLinkedBlockIngQueue.Node first = h.next;
h.next = h; // help GC
head = first;
E x = first.item;
first.item = null;
return x;
}
/**
* Locks to prevent both puts and takes.
*/
void fullyLock() {
putLock.lock();
takeLock.lock();
}
/**
* Unlocks to allow both puts and takes.
*/
void fullyUnlock() {
takeLock.unlock();
putLock.unlock();
}
// /**
// * Tells whether both locks are held by current thread.
// */
// boolean isFullyLocked() {
// return (putLock.isHeldByCurrentThread() &&
// takeLock.isHeldByCurrentThread());
// }
/**
* Creates a {@code ResizableCapacityLinkedBlockIngQueue} with a capacity of
* {@link Integer#MAX_VALUE}.
*/
public ResizableCapacityLinkedBlockIngQueue() {
this(Integer.MAX_VALUE);
}
/**
* Creates a {@code ResizableCapacityLinkedBlockIngQueue} with the given (fixed) capacity.
*
* @param capacity the capacity of this queue
* @throws IllegalArgumentException if {@code capacity} is not greater
* than zero
*/
public ResizableCapacityLinkedBlockIngQueue(int capacity) {
if (capacity <= 0) {
throw new IllegalArgumentException();
}
this.capacity = capacity;
last = head = new ResizableCapacityLinkedBlockIngQueue.Node(null);
}
/**
* Creates a {@code ResizableCapacityLinkedBlockIngQueue} with a capacity of
* {@link Integer#MAX_VALUE}, initially containing the elements of the
* given collection,
* added in traversal order of the collection's iterator.
*
* @param c the collection of elements to initially contain
* @throws NullPointerException if the specified collection or any
* of its elements are null
*/
public ResizableCapacityLinkedBlockIngQueue(Collection c) {
this(Integer.MAX_VALUE);
final ReentrantLock putLock = this.putLock;
putLock.lock(); // Never contended, but necessary for visibility
try {
int n = 0;
for (E e : c) {
if (e == null) {
throw new NullPointerException();
}
if (n == capacity) {
throw new IllegalStateException("Queue full");
}
enqueue(new ResizableCapacityLinkedBlockIngQueue.Node(e));
++n;
}
count.set(n);
} finally {
putLock.unlock();
}
}
// this doc comment is overridden to remove the reference to collections
// greater in size than Integer.MAX_VALUE
/**
* Returns the number of elements in this queue.
*
* @return the number of elements in this queue
*/
@Override
public int size() {
return count.get();
}
// this doc comment is a modified copy of the inherited doc comment,
// without the reference to unlimited queues.
/**
* Returns the number of additional elements that this queue can ideally
* (in the absence of memory or resource constraints) accept without
* blocking. This is always equal to the initial capacity of this queue
* less the current {@code size} of this queue.
*
* Note that you cannot always tell if an attempt to insert
* an element will succeed by inspecting {@code remainingCapacity}
* because it may be the case that another thread is about to
* insert or remove an element.
*/
@Override
public int remainingCapacity() {
return capacity - count.get();
}
/**
* Inserts the specified element at the tail of this queue, waiting if
* necessary for space to become available.
*
* @throws InterruptedException {@inheritDoc}
* @throws NullPointerException {@inheritDoc}
*/
@Override
public void put(E e) throws InterruptedException {
if (e == null) {
throw new NullPointerException();
}
// Note: convention in all put/take/etc is to preset local var
// holding count negative to indicate failure unless set.
int c = -1;
ResizableCapacityLinkedBlockIngQueue.Node node = new ResizableCapacityLinkedBlockIngQueue.Node(e);
final ReentrantLock putLock = this.putLock;
final AtomicInteger count = this.count;
putLock.lockInterruptibly();
try {
/*
* Note that count is used in wait guard even though it is
* not protected by lock. This works because count can
* only decrease at this point (all other puts are shut
* out by lock), and we (or some other waiting put) are
* signalled if it ever changes from capacity. Similarly
* for all other uses of count in other wait guards.
*/
while (count.get() == capacity) {
notFull.await();
}
enqueue(node);
c = count.getAndIncrement();
if (c + 1 < capacity) {
notFull.signal();
}
} finally {
putLock.unlock();
}
if (c == 0) {
signalNotEmpty();
}
}
/**
* Inserts the specified element at the tail of this queue, waiting if
* necessary up to the specified wait time for space to become available.
*
* @return {@code true} if successful, or {@code false} if
* the specified waiting time elapses before space is available
* @throws InterruptedException {@inheritDoc}
* @throws NullPointerException {@inheritDoc}
*/
@Override
public boolean offer(E e, long timeout, TimeUnit unit)
throws InterruptedException {
if (e == null) {
throw new NullPointerException();
}
long nanos = unit.toNanos(timeout);
int c = -1;
final ReentrantLock putLock = this.putLock;
final AtomicInteger count = this.count;
putLock.lockInterruptibly();
try {
while (count.get() == capacity) {
if (nanos <= 0) {
return false;
}
nanos = notFull.awaitNanos(nanos);
}
enqueue(new ResizableCapacityLinkedBlockIngQueue.Node(e));
c = count.getAndIncrement();
if (c + 1 < capacity) {
notFull.signal();
}
} finally {
putLock.unlock();
}
if (c == 0) {
signalNotEmpty();
}
return true;
}
/**
* Inserts the specified element at the tail of this queue if it is
* possible to do so immediately without exceeding the queue's capacity,
* returning {@code true} upon success and {@code false} if this queue
* is full.
* When using a capacity-restricted queue, this method is generally
* preferable to method {@link BlockingQueue#add add}, which can fail to
* insert an element only by throwing an exception.
*
* @throws NullPointerException if the specified element is null
*/
@Override
public boolean offer(E e) {
if (e == null) {
throw new NullPointerException();
}
final AtomicInteger count = this.count;
if (count.get() == capacity) {
return false;
}
int c = -1;
ResizableCapacityLinkedBlockIngQueue.Node node = new ResizableCapacityLinkedBlockIngQueue.Node(e);
final ReentrantLock putLock = this.putLock;
putLock.lock();
try {
if (count.get() < capacity) {
enqueue(node);
c = count.getAndIncrement();
if (c + 1 < capacity) {
notFull.signal();
}
}
} finally {
putLock.unlock();
}
if (c == 0) {
signalNotEmpty();
}
return c >= 0;
}
@Override
public E take() throws InterruptedException {
E x;
int c = -1;
final AtomicInteger count = this.count;
final ReentrantLock takeLock = this.takeLock;
takeLock.lockInterruptibly();
try {
while (count.get() == 0) {
notEmpty.await();
}
x = dequeue();
c = count.getAndDecrement();
if (c > 1) {
notEmpty.signal();
}
} finally {
takeLock.unlock();
}
if (c == capacity) {
signalNotFull();
}
return x;
}
@Override
public E poll(long timeout, TimeUnit unit) throws InterruptedException {
E x = null;
int c = -1;
long nanos = unit.toNanos(timeout);
final AtomicInteger count = this.count;
final ReentrantLock takeLock = this.takeLock;
takeLock.lockInterruptibly();
try {
while (count.get() == 0) {
if (nanos <= 0) {
return null;
}
nanos = notEmpty.awaitNanos(nanos);
}
x = dequeue();
c = count.getAndDecrement();
if (c > 1) {
notEmpty.signal();
}
} finally {
takeLock.unlock();
}
if (c == capacity) {
signalNotFull();
}
return x;
}
@Override
public E poll() {
final AtomicInteger count = this.count;
if (count.get() == 0) {
return null;
}
E x = null;
int c = -1;
final ReentrantLock takeLock = this.takeLock;
takeLock.lock();
try {
if (count.get() > 0) {
x = dequeue();
c = count.getAndDecrement();
if (c > 1) {
notEmpty.signal();
}
}
} finally {
takeLock.unlock();
}
if (c == capacity) {
signalNotFull();
}
return x;
}
@Override
public E peek() {
if (count.get() == 0) {
return null;
}
final ReentrantLock takeLock = this.takeLock;
takeLock.lock();
try {
ResizableCapacityLinkedBlockIngQueue.Node first = head.next;
if (first == null) {
return null;
} else {
return first.item;
}
} finally {
takeLock.unlock();
}
}
/**
* Unlinks interior Node p with predecessor trail.
*/
void unlink(ResizableCapacityLinkedBlockIngQueue.Node p, ResizableCapacityLinkedBlockIngQueue.Node trail) {
// assert isFullyLocked();
// p.next is not changed, to allow iterators that are
// traversing p to maintain their weak-consistency guarantee.
p.item = null;
trail.next = p.next;
if (last == p) {
last = trail;
}
if (count.getAndDecrement() == capacity) {
notFull.signal();
}
}
/**
* Removes a single instance of the specified element from this queue,
* if it is present. More formally, removes an element {@code e} such
* that {@code o.equals(e)}, if this queue contains one or more such
* elements.
* Returns {@code true} if this queue contained the specified element
* (or equivalently, if this queue changed as a result of the call).
*
* @param o element to be removed from this queue, if present
* @return {@code true} if this queue changed as a result of the call
*/
@Override
public boolean remove(Object o) {
if (o == null) {
return false;
}
fullyLock();
try {
for (ResizableCapacityLinkedBlockIngQueue.Node trail = head, p = trail.next;
p != null;
trail = p, p = p.next) {
if (o.equals(p.item)) {
unlink(p, trail);
return true;
}
}
return false;
} finally {
fullyUnlock();
}
}
/**
* Returns {@code true} if this queue contains the specified element.
* More formally, returns {@code true} if and only if this queue contains
* at least one element {@code e} such that {@code o.equals(e)}.
*
* @param o object to be checked for containment in this queue
* @return {@code true} if this queue contains the specified element
*/
@Override
public boolean contains(Object o) {
if (o == null) {
return false;
}
fullyLock();
try {
for (ResizableCapacityLinkedBlockIngQueue.Node p = head.next; p != null; p = p.next) {
if (o.equals(p.item)) {
return true;
}
}
return false;
} finally {
fullyUnlock();
}
}
/**
* Returns an array containing all of the elements in this queue, in
* proper sequence.
*
* The returned array will be "safe" in that no references to it are
* maintained by this queue. (In other words, this method must allocate
* a new array). The caller is thus free to modify the returned array.
*
*
This method acts as bridge between array-based and collection-based
* APIs.
*
* @return an array containing all of the elements in this queue
*/
@Override
public Object[] toArray() {
fullyLock();
try {
int size = count.get();
Object[] a = new Object[size];
int k = 0;
for (ResizableCapacityLinkedBlockIngQueue.Node p = head.next; p != null; p = p.next) {
a[k++] = p.item;
}
return a;
} finally {
fullyUnlock();
}
}
/**
* Returns an array containing all of the elements in this queue, in
* proper sequence; the runtime type of the returned array is that of
* the specified array. If the queue fits in the specified array, it
* is returned therein. Otherwise, a new array is allocated with the
* runtime type of the specified array and the size of this queue.
*
* If this queue fits in the specified array with room to spare
* (i.e., the array has more elements than this queue), the element in
* the array immediately following the end of the queue is set to
* {@code null}.
*
*
Like the {@link #toArray()} method, this method acts as bridge between
* array-based and collection-based APIs. Further, this method allows
* precise control over the runtime type of the output array, and may,
* under certain circumstances, be used to save allocation costs.
*
*
Suppose {@code x} is a queue known to contain only strings.
* The following code can be used to dump the queue into a newly
* allocated array of {@code String}:
*
*
{@code String[] y = x.toArray(new String[0]);}
*
* Note that {@code toArray(new Object[0])} is identical in function to
* {@code toArray()}.
*
* @param a the array into which the elements of the queue are to
* be stored, if it is big enough; otherwise, a new array of the
* same runtime type is allocated for this purpose
* @return an array containing all of the elements in this queue
* @throws ArrayStoreException if the runtime type of the specified array
* is not a supertype of the runtime type of every element in
* this queue
* @throws NullPointerException if the specified array is null
*/
@Override
@SuppressWarnings("unchecked")
public T[] toArray(T[] a) {
fullyLock();
try {
int size = count.get();
if (a.length < size) {
a = (T[]) java.lang.reflect.Array.newInstance
(a.getClass().getComponentType(), size);
}
int k = 0;
for (ResizableCapacityLinkedBlockIngQueue.Node p = head.next; p != null; p = p.next) {
a[k++] = (T) p.item;
}
if (a.length > k) {
a[k] = null;
}
return a;
} finally {
fullyUnlock();
}
}
@Override
public String toString() {
fullyLock();
try {
ResizableCapacityLinkedBlockIngQueue.Node p = head.next;
if (p == null) {
return "[]";
}
StringBuilder sb = new StringBuilder();
sb.append('[');
for (; ; ) {
E e = p.item;
sb.append(e == this ? "(this Collection)" : e);
p = p.next;
if (p == null) {
return sb.append(']').toString();
}
sb.append(',').append(' ');
}
} finally {
fullyUnlock();
}
}
/**
* Atomically removes all of the elements from this queue.
* The queue will be empty after this call returns.
*/
@Override
public void clear() {
fullyLock();
try {
for (ResizableCapacityLinkedBlockIngQueue.Node p, h = head; (p = h.next) != null; h = p) {
h.next = h;
p.item = null;
}
head = last;
// assert head.item == null && head.next == null;
if (count.getAndSet(0) == capacity) {
notFull.signal();
}
} finally {
fullyUnlock();
}
}
/**
* @throws UnsupportedOperationException {@inheritDoc}
* @throws ClassCastException {@inheritDoc}
* @throws NullPointerException {@inheritDoc}
* @throws IllegalArgumentException {@inheritDoc}
*/
@Override
public int drainTo(Collection c) {
return drainTo(c, Integer.MAX_VALUE);
}
/**
* @throws UnsupportedOperationException {@inheritDoc}
* @throws ClassCastException {@inheritDoc}
* @throws NullPointerException {@inheritDoc}
* @throws IllegalArgumentException {@inheritDoc}
*/
@Override
public int drainTo(Collection c, int maxElements) {
if (c == null) {
throw new NullPointerException();
}
if (c == this) {
throw new IllegalArgumentException();
}
if (maxElements <= 0) {
return 0;
}
boolean signalNotFull = false;
final ReentrantLock takeLock = this.takeLock;
takeLock.lock();
try {
int n = Math.min(maxElements, count.get());
// count.get provides visibility to first n Nodes
ResizableCapacityLinkedBlockIngQueue.Node h = head;
int i = 0;
try {
while (i < n) {
ResizableCapacityLinkedBlockIngQueue.Node p = h.next;
c.add(p.item);
p.item = null;
h.next = h;
h = p;
++i;
}
return n;
} finally {
// Restore invariants even if c.add() threw
if (i > 0) {
// assert h.item == null;
head = h;
signalNotFull = (count.getAndAdd(-i) == capacity);
}
}
} finally {
takeLock.unlock();
if (signalNotFull) {
signalNotFull();
}
}
}
/**
* Returns an iterator over the elements in this queue in proper sequence.
* The elements will be returned in order from first (head) to last (tail).
*
* The returned iterator is
* weakly consistent.
*
* @return an iterator over the elements in this queue in proper sequence
*/
@Override
public Iterator iterator() {
return new ResizableCapacityLinkedBlockIngQueue.Itr();
}
private class Itr implements Iterator {
/*
* Basic weakly-consistent iterator. At all times hold the next
* item to hand out so that if hasNext() reports true, we will
* still have it to return even if lost race with a take etc.
*/
private ResizableCapacityLinkedBlockIngQueue.Node current;
private ResizableCapacityLinkedBlockIngQueue.Node lastRet;
private E currentElement;
Itr() {
fullyLock();
try {
current = head.next;
if (current != null) {
currentElement = current.item;
}
} finally {
fullyUnlock();
}
}
@Override
public boolean hasNext() {
return current != null;
}
/**
* Returns the next live successor of p, or null if no such.
*
* Unlike other traversal methods, iterators need to handle both:
* - dequeued nodes (p.next == p)
* - (possibly multiple) interior removed nodes (p.item == null)
*/
private ResizableCapacityLinkedBlockIngQueue.Node nextNode(ResizableCapacityLinkedBlockIngQueue.Node p) {
for (; ; ) {
ResizableCapacityLinkedBlockIngQueue.Node s = p.next;
if (s == p) {
return head.next;
}
if (s == null || s.item != null) {
return s;
}
p = s;
}
}
@Override
public E next() {
fullyLock();
try {
if (current == null) {
throw new NoSuchElementException();
}
E x = currentElement;
lastRet = current;
current = nextNode(current);
currentElement = (current == null) ? null : current.item;
return x;
} finally {
fullyUnlock();
}
}
@Override
public void remove() {
if (lastRet == null) {
throw new IllegalStateException();
}
fullyLock();
try {
ResizableCapacityLinkedBlockIngQueue.Node node = lastRet;
lastRet = null;
for (ResizableCapacityLinkedBlockIngQueue.Node trail = head, p = trail.next;
p != null;
trail = p, p = p.next) {
if (p == node) {
unlink(p, trail);
break;
}
}
} finally {
fullyUnlock();
}
}
}
/**
* A customized variant of Spliterators.IteratorSpliterator
*/
static final class LBQSpliterator implements Spliterator {
static final int MAX_BATCH = 1 << 25; // max batch array size;
final ResizableCapacityLinkedBlockIngQueue queue;
ResizableCapacityLinkedBlockIngQueue.Node current; // current node; null until initialized
int batch; // batch size for splits
boolean exhausted; // true when no more nodes
long est; // size estimate
LBQSpliterator(ResizableCapacityLinkedBlockIngQueue queue) {
this.queue = queue;
this.est = queue.size();
}
@Override
public long estimateSize() {
return est;
}
@Override
public Spliterator trySplit() {
ResizableCapacityLinkedBlockIngQueue.Node h;
final ResizableCapacityLinkedBlockIngQueue q = this.queue;
int b = batch;
int n = (b <= 0) ? 1 : (b >= MAX_BATCH) ? MAX_BATCH : b + 1;
if (!exhausted &&
((h = current) != null || (h = q.head.next) != null) &&
h.next != null) {
Object[] a = new Object[n];
int i = 0;
ResizableCapacityLinkedBlockIngQueue.Node p = current;
q.fullyLock();
try {
if (p != null || (p = q.head.next) != null) {
do {
if ((a[i] = p.item) != null) {
++i;
}
} while ((p = p.next) != null && i < n);
}
} finally {
q.fullyUnlock();
}
if ((current = p) == null) {
est = 0L;
exhausted = true;
} else if ((est -= i) < 0L) {
est = 0L;
}
if (i > 0) {
batch = i;
return Spliterators.spliterator
(a, 0, i, Spliterator.ORDERED | Spliterator.NONNULL |
Spliterator.CONCURRENT);
}
}
return null;
}
@Override
public void forEachRemaining(Consumer action) {
if (action == null) {
throw new NullPointerException();
}
final ResizableCapacityLinkedBlockIngQueue q = this.queue;
if (!exhausted) {
exhausted = true;
ResizableCapacityLinkedBlockIngQueue.Node p = current;
do {
E e = null;
q.fullyLock();
try {
if (p == null) {
p = q.head.next;
}
while (p != null) {
e = p.item;
p = p.next;
if (e != null) {
break;
}
}
} finally {
q.fullyUnlock();
}
if (e != null) {
action.accept(e);
}
} while (p != null);
}
}
@Override
public boolean tryAdvance(Consumer action) {
if (action == null) {
throw new NullPointerException();
}
final ResizableCapacityLinkedBlockIngQueue q = this.queue;
if (!exhausted) {
E e = null;
q.fullyLock();
try {
if (current == null) {
current = q.head.next;
}
while (current != null) {
e = current.item;
current = current.next;
if (e != null) {
break;
}
}
} finally {
q.fullyUnlock();
}
if (current == null) {
exhausted = true;
}
if (e != null) {
action.accept(e);
return true;
}
}
return false;
}
@Override
public int characteristics() {
return Spliterator.ORDERED | Spliterator.NONNULL |
Spliterator.CONCURRENT;
}
}
/**
* Returns a {@link Spliterator} over the elements in this queue.
*
* The returned spliterator is
* weakly consistent.
*
*
The {@code Spliterator} reports {@link Spliterator#CONCURRENT},
* {@link Spliterator#ORDERED}, and {@link Spliterator#NONNULL}.
*
* @return a {@code Spliterator} over the elements in this queue
* @implNote The {@code Spliterator} implements {@code trySplit} to permit limited
* parallelism.
* @since 1.8
*/
@Override
public Spliterator spliterator() {
return new ResizableCapacityLinkedBlockIngQueue.LBQSpliterator(this);
}
/**
* Saves this queue to a stream (that is, serializes it).
*
* @param s the stream
* @throws java.io.IOException if an I/O error occurs
* @serialData The capacity is emitted (int), followed by all of
* its elements (each an {@code Object}) in the proper order,
* followed by a null
*/
private void writeObject(java.io.ObjectOutputStream s)
throws java.io.IOException {
fullyLock();
try {
// Write out any hidden stuff, plus capacity
s.defaultWriteObject();
// Write out all elements in the proper order.
for (ResizableCapacityLinkedBlockIngQueue.Node p = head.next; p != null; p = p.next) {
s.writeObject(p.item);
}
// Use trailing null as sentinel
s.writeObject(null);
} finally {
fullyUnlock();
}
}
/**
* Reconstitutes this queue from a stream (that is, deserializes it).
*
* @param s the stream
* @throws ClassNotFoundException if the class of a serialized object
* could not be found
* @throws java.io.IOException if an I/O error occurs
*/
private void readObject(java.io.ObjectInputStream s)
throws java.io.IOException, ClassNotFoundException {
// Read in capacity, and any hidden stuff
s.defaultReadObject();
count.set(0);
last = head = new ResizableCapacityLinkedBlockIngQueue.Node(null);
// Read in all elements and place in queue
for (; ; ) {
@SuppressWarnings("unchecked")
E item = (E) s.readObject();
if (item == null) {
break;
}
add(item);
}
}
public void setCapacity(int capacity) {
this.capacity = capacity;
}
}
3、动态线程池管理
/**
* @Description 动态线程池管理
* @Date 2021/12/4 4:20 下午
* @Author chenzhibin
*/
public class DynamicThreadPoolManager {
/**
* 存储线程池对象，Key:名称 Value:对象
*/
private Map threadPoolExecutorMap = new HashMap<>();
/**
* 存储线程池拒绝次数，Key:名称 Value:次数
*/
private static Map threadPoolExecutorRejectCountMap = new ConcurrentHashMap<>();
public void createThreadPool(ThreadPoolParam param) {
createThreadPoolExecutor(param);
}
/**
* 创建线程池
*
* @param threadPoolParam
*/
private void createThreadPoolExecutor(ThreadPoolParam threadPoolParam) {
if (!threadPoolExecutorMap.containsKey(threadPoolParam.getThreadPoolName())) {
DynamicThreadPoolExecutor threadPoolExecutor = new DynamicThreadPoolExecutor(
threadPoolParam.getCorePoolSize(),
threadPoolParam.getMaximumPoolSize(),
threadPoolParam.getKeepAliveTime(),
threadPoolParam.getUnit(),
getBlockingQueue(threadPoolParam.getQueueType(), threadPoolParam.getQueueCapacity(), threadPoolParam.isFair()),
new DefaultThreadFactory(threadPoolParam.getThreadPoolName()),
getRejectedExecutionHandler(threadPoolParam.getRejectedExecutionType(), threadPoolParam.getThreadPoolName()), threadPoolParam.getThreadPoolName());
threadPoolExecutorMap.put(threadPoolParam.getThreadPoolName(), threadPoolExecutor);
}
}
/**
* 根据线程池昵称获取线程池
*
* @param threadPoolName
* @return
*/
public DynamicThreadPoolExecutor getThreadPoolExecutor(String threadPoolName) {
DynamicThreadPoolExecutor threadPoolExecutor = threadPoolExecutorMap.get(threadPoolName);
if (threadPoolExecutor == null) {
return null;
}
return threadPoolExecutor;
}
/**
* 获取阻塞队列
*
* @param queueType
* @param queueCapacity
* @param fair
* @return
*/
private BlockingQueue getBlockingQueue(String queueType, int queueCapacity, boolean fair) {
if (!QueueTypeEnum.exists(queueType)) {
throw new RuntimeException("队列不存在 " + queueType);
}
if (QueueTypeEnum.ARRAY_BLOCKING_QUEUE.getType().equals(queueType)) {
return new ArrayBlockingQueue(queueCapacity);
}
if (QueueTypeEnum.SYNCHRONOUS_QUEUE.getType().equals(queueType)) {
return new SynchronousQueue(fair);
}
if (QueueTypeEnum.PRIORITY_BLOCKING_QUEUE.getType().equals(queueType)) {
return new PriorityBlockingQueue(queueCapacity);
}
if (QueueTypeEnum.DELAY_QUEUE.getType().equals(queueType)) {
return new DelayQueue();
}
if (QueueTypeEnum.LINKED_BLOCKING_DEQUE.getType().equals(queueType)) {
return new LinkedBlockingDeque(queueCapacity);
}
if (QueueTypeEnum.LINKED_TRANSFER_DEQUE.getType().equals(queueType)) {
return new LinkedTransferQueue();
}
return new ResizableCapacityLinkedBlockIngQueue(queueCapacity);
}
/**
* 获取拒绝策略
*
* @param rejectedExecutionType
* @param threadPoolName
* @return
*/
private RejectedExecutionHandler getRejectedExecutionHandler(String rejectedExecutionType, String threadPoolName) {
if (RejectedExecutionHandlerEnum.CALLER_RUNS_POLICY.getType().equals(rejectedExecutionType)) {
return new ThreadPoolExecutor.CallerRunsPolicy();
}
if (RejectedExecutionHandlerEnum.DISCARD_OLDEST_POLICY.getType().equals(rejectedExecutionType)) {
return new ThreadPoolExecutor.DiscardOldestPolicy();
}
if (RejectedExecutionHandlerEnum.DISCARD_POLICY.getType().equals(rejectedExecutionType)) {
return new ThreadPoolExecutor.DiscardPolicy();
}
ServiceLoader serviceLoader = ServiceLoader.load(RejectedExecutionHandler.class);
Iterator iterator = serviceLoader.iterator();
while (iterator.hasNext()) {
RejectedExecutionHandler rejectedExecutionHandler = iterator.next();
String rejectedExecutionHandlerName = rejectedExecutionHandler.getClass().getSimpleName();
if (rejectedExecutionType.equals(rejectedExecutionHandlerName)) {
return rejectedExecutionHandler;
}
}
return new DefaultAbortPolicy(threadPoolName);
}
static class DefaultThreadFactory implements ThreadFactory {
private static final AtomicInteger poolNumber = new AtomicInteger(1);
private final ThreadGroup group;
private final AtomicInteger threadNumber = new AtomicInteger(1);
private final String namePrefix;
DefaultThreadFactory(String threadPoolName) {
SecurityManager s = System.getSecurityManager();
group = (s != null) ? s.getThreadGroup() :
Thread.currentThread().getThreadGroup();
namePrefix = threadPoolName + "-" + poolNumber.getAndIncrement() + "-thread-";
}
@Override
public Thread newThread(Runnable r) {
Thread t = new Thread(group, r,
namePrefix + threadNumber.getAndIncrement(),
0);
if (t.isDaemon()) {
t.setDaemon(false);
}
if (t.getPriority() != Thread.NORM_PRIORITY) {
t.setPriority(Thread.NORM_PRIORITY);
}
return t;
}
}
static class DefaultAbortPolicy implements RejectedExecutionHandler {
private String threadPoolName;
/**
* Creates an {@code AbortPolicy}.
*/
public DefaultAbortPolicy() {
}
public DefaultAbortPolicy(String threadPoolName) {
this.threadPoolName = threadPoolName;
}
/**
* Always throws RejectedExecutionException.
*
* @param r the runnable task requested to be executed
* @param e the executor attempting to execute this task
* @throws RejectedExecutionException always
*/
@Override
public void rejectedExecution(Runnable r, ThreadPoolExecutor e) {
AtomicLong atomicLong = threadPoolExecutorRejectCountMap.putIfAbsent(threadPoolName, new AtomicLong(1));
if (atomicLong != null) {
atomicLong.incrementAndGet();
}
throw new RejectedExecutionException("Task " + r.toString() + " rejected from " + e.toString());
}
}
/**
* 刷新线程池
*/
public synchronized void refreshThreadPoolExecutor(List params) {
if (params != null && params.size() != 0) {
params.forEach(param -> {
if (threadPoolExecutorMap.containsKey(param.getThreadPoolName())) {
if (param.getCorePoolSize() <= 0) {
throw new IllegalArgumentException(param.getThreadPoolName() + " corePoolSize must be grater than zero");
}
if (param.getMaximumPoolSize() <= 0) {
throw new IllegalArgumentException(param.getThreadPoolName() + " getMaximumPoolSize must be grater than zero");
}
// 如果核心线程数大于最大线程数，不成立，抛出异常IllegalArgumentException
if (param.getCorePoolSize() > param.getMaximumPoolSize()) {
throw new IllegalArgumentException(param.getThreadPoolName() + " corePoolSize must not bigger than maxPoolSize");
}
if (param.getQueueCapacity() <= 0) {
throw new IllegalArgumentException("Dynamic Thread [" + param.getThreadPoolName() + "] update error, queueCapacity must be grater than zero.");
}
DynamicThreadPoolExecutor threadPoolExecutor = threadPoolExecutorMap.get(param.getThreadPoolName());
//判断值是否发送变化
if (checkUpdate(param, threadPoolExecutor)) {
// 为了防止修改时最大线程数小于原核心线程数导致更新失败，所以更新时需要按照值大小排序更新
setThreadSize(param, threadPoolExecutor);
threadPoolExecutor.setKeepAliveTime(param.getKeepAliveTime(), param.getUnit());
threadPoolExecutor.setRejectedExecutionHandler(getRejectedExecutionHandler(param.getRejectedExecutionType(), param.getThreadPoolName()));
}
BlockingQueue queue = threadPoolExecutor.getQueue();
if (queue != null && queue instanceof ResizableCapacityLinkedBlockIngQueue) {
((ResizableCapacityLinkedBlockIngQueue) queue).setCapacity(param.getQueueCapacity());
}
}
});
}
}
/**
* 正确更新核心线程数和最大线程数方式
*
* @param param
* @param threadPoolExecutor
*/
private void setThreadSize(ThreadPoolParam param, DynamicThreadPoolExecutor threadPoolExecutor) {
if (param.getCorePoolSize() <= threadPoolExecutor.getCorePoolSize()) {
threadPoolExecutor.setCorePoolSize(param.getCorePoolSize());
threadPoolExecutor.setMaximumPoolSize(param.getMaximumPoolSize());
} else {
threadPoolExecutor.setMaximumPoolSize(param.getMaximumPoolSize());
threadPoolExecutor.setCorePoolSize(param.getCorePoolSize());
}
}
/**
* 验证更新项是否发生变化
*
* @param param
* @param threadPoolExecutor
* @return
*/
private boolean checkUpdate(ThreadPoolParam param, DynamicThreadPoolExecutor threadPoolExecutor) {
if (param.getCorePoolSize() != threadPoolExecutor.getCorePoolSize()) {
return true;
}
if (param.getMaximumPoolSize() != threadPoolExecutor.getMaximumPoolSize()) {
return true;
}
if (param.getKeepAliveTime() != threadPoolExecutor.getKeepAliveTime(TimeUnit.SECONDS)) {
return true;
}
if (!param.getRejectedExecutionType().equalsIgnoreCase(threadPoolExecutor.getRejectedExecutionHandler().getClass().getSimpleName())) {
return true;
}
return false;
}
/**
* 获取当前服务所有的线程池
*
* @return
*/
public List getCurrentAppThreadPoolExecutors() {
List dynamicThreadPoolExecutors = new ArrayList<>();
if (threadPoolExecutorMap.size() != 0) {
Iterator> iterator = threadPoolExecutorMap.entrySet().iterator();
while (iterator.hasNext()) {
Map.Entry threadPoolExecutorEntry = iterator.next();
if (threadPoolExecutorEntry.getValue() != null) {
dynamicThreadPoolExecutors.add(threadPoolExecutorEntry.getValue());
}
}
}
return dynamicThreadPoolExecutors;
}
/**
* 获取拒绝数量
*
* @param threadPoolName
* @return
*/
public Long getRejectCount(String threadPoolName) {
if (StringUtils.isBlank(threadPoolName)) {
return 0L;
}
AtomicLong val = threadPoolExecutorRejectCountMap.get(threadPoolName);
if (val == null) {
return 0L;
}
return val.get();
}
}
4、定义一个默认的创建线程池的参数
/**
* @Description 线程池参数
* @Date 2021/12/4 5:06 下午
* @Author chenzhibin
*/
@Data
@AllArgsConstructor
@NoArgsConstructor
@Builder
public class ThreadPoolParam {
/**
* 线程池名称
*/
private String threadPoolName = "DefaultThreadPool";
/**
* 核心线程数
*/
private Integer corePoolSize = 1;
/**
* 最大线程数, 默认值为CPU核心数量
*/
private Integer maximumPoolSize = Runtime.getRuntime().availableProcessors();
/**
* 队列最大数量，默认1000，不用Integer.MAX_VALUE防止OOM
*/
private Integer queueCapacity = 1000;
/**
* 队列类型
*
* @see QueueTypeEnum
*/
private String queueType = QueueTypeEnum.LINKED_BLOCKING_QUEUE.getType();
/**
* SynchronousQueue 是否公平策略
*/
private boolean fair;
/**
* 拒绝策略
*
* @see RejectedExecutionHandlerEnum
*/
private String rejectedExecutionType = RejectedExecutionHandlerEnum.ABORT_POLICY.getType();
/**
* 空闲线程存活时间,默认15s
*/
private Long keepAliveTime = 15L;
/**
* 空闲线程存活时间单位，默认s
*/
private TimeUnit unit = TimeUnit.SECONDS;
/**
* 队列容量阀值
*/
private Integer queueCapacityThreshold = queueCapacity;
}
好了，这些代码弄好以后该怎么使用呢？
在SpringBoot中：
首先将动态线程池管理者交给Spring管理，并设置监听线程池的定时任务线程池大小，1就可以了
/**
* @Description 本服务设置
* @Date 2021/12/6 4:25 下午
* @Author chenzhibin
*/
@Configuration
public class AppConfig {
@Bean
public DynamicThreadPoolManager dynamicThreadPoolManager() {
return new DynamicThreadPoolManager();
}
/**
* 设置定时任务线程池大小
*
* @return
*/
@Bean
public TaskScheduler taskScheduler() {
ThreadPoolTaskScheduler taskScheduler = new ThreadPoolTaskScheduler();
//设置线程池大小
taskScheduler.setPoolSize(1);
return taskScheduler;
}
}
然后在项目初始化时监听分布式配置中心，并创建线程池，根据自己业务需要可以创建多个。
/**
* @Description 分布式配置中心
* @Date 2021/12/6 3:52 下午
* @Author chenzhibin
*/
@Component
@Slf4j
public class ConfigurationService implements InitializingBean {
public static class Key {
/**
* 动态线程池
*/
public static final String THREAD_POOL_KEY = "dynamicThreadPool";
}
private final Map proper = new ConcurrentHashMap<>();
private final String GROUP_ID = "xx";
private final String SERVICE_ID = "xxx";
@Resource
private DynamicThreadPoolManager dynamicThreadPoolManager;
@Override
public void afterPropertiesSet() throws Exception {
initVitamin();
initThreadPool();
}
private void initVitamin() {
log.info("before proper={}", JSON.toJSONString(proper));
// 加载分布式配置项至本地，并注册配置项变更的监听器
Map nodeMap =lookup(GROUP_ID, SERVICE_ID, nodes -> {
handlerNode(nodes);
});
if (MapUtils.isNotEmpty(nodeMap)) {
proper.putAll(nodeMap);
}
log.info("before after={}", JSON.toJSONString(proper));
}
/**
* 初始化线程池
*/
private void initThreadPool() {
List threadPoolParams = new ArrayList<>();
try {
threadPoolParams = jsonStrToList(Key.THREAD_POOL_KEY, ThreadPoolParam.class);
} catch (Exception e) {
log.error("threadPool param illegal e :{}", e);
}
ThreadPoolParam msgPoolParam = ExecutorUtils.getMsgPoolParam();
ThreadPoolParam dbPoolParam = ExecutorUtils.getDbPoolParam();
for (ThreadPoolParam param : threadPoolParams) {
if (param.getThreadPoolName().equals(msgPoolParam.getThreadPoolName())) {
dynamicThreadPoolManager.createThreadPool(param);
} else {
dynamicThreadPoolManager.createThreadPool(msgPoolParam);
}
if (param.getThreadPoolName().equals(dbPoolParam.getThreadPoolName())) {
dynamicThreadPoolManager.createThreadPool(param);
} else {
dynamicThreadPoolManager.createThreadPool(dbPoolParam);
}
}
}
private void handlerNode(List nodes) {
if (CollectionUtils.isEmpty(nodes)) {
return;
}
for (NodeDO nodeDO : nodes) {
if (nodeDO == null) {
continue;
}
if (nodeDO.getOperateType() == NodeDO.OperateType.DELETE) {
removeValue(nodeDO.getNodeKey());
}
putValue(nodeDO.getNodeKey(), nodeDO.getNodeValue());
try {
if (nodeDO.getNodeKey().equals(Key.THREAD_POOL_KEY)) {
List threadPoolParams = jsonStrToList(Key.THREAD_POOL_KEY, ThreadPoolParam.class);
dynamicThreadPoolManager.refreshThreadPoolExecutor(threadPoolParams);
log.info("refresh threadPool success!,new threadPoolParams={}", nodeDO.getNodeValue());
}
} catch (Exception e) {
log.error("refreshThreadPoolExecutor fail,param illegal");
}
}
}
private void removeValue(String nodeKey) {
proper.remove(nodeKey);
}
private void putValue(String key, String value) {
proper.put(key, value);
log.info("put key ={},value ={}", key, value);
}
public T getValue(String key, TypeReference type) {
T t = null;
String value = getValue(key);
t = JSON.parseObject(value, type);
log.info("get value key={},value={}", key, t);
return t;
}
private String getValue(String key) {
String v;
v = proper.get(key);
return v;
}
public List jsonStrToList(String key, Class clazz) {
String v;
v = proper.get(key);
List res = (List) JSONArray.parseArray(v, clazz);
return res;
}
}
分布式配置中心设置key,val
key ="dynamicThreadPoool"
val=
"[{"threadPoolName":"default","corePoolSize":1500,"maximumPoolSize":3000,"keepAliveTime":30,"queueType":"LinkedBlockingQueue","rejectedExecutionType":"AbortPolicy","queueCapacity":1000}]"
最后就是定时任务监听线程池状态：
/**
* @Description 定时任务
* 注意：添加其他任务时需要在AppConfig判断线程池数够不够使用，不够自己调整
* @Date 2021/12/28 5:35 下午
* @Author chenzhibin
*/
@Component
@Slf4j(topic = "monitorLogger")
public class TimeTask {
@Resource
private DynamicThreadPoolManager dynamicThreadPoolManager;
/**
* 监控线程池状态,每3秒打印一次
*/
@Scheduled(cron = "0/3 * * * * *")
public void monitorThreadPool() {
List executors = dynamicThreadPoolManager.getCurrentAppThreadPoolExecutors();
if (CollectionUtils.isNotEmpty(executors)) {
executors.forEach(dynamicThreadPoolExecutor -> {
String threadPoolName = dynamicThreadPoolExecutor.getThreadPoolName();
//当前线程数
int currentThreadSize = dynamicThreadPoolExecutor.getPoolSize();
//核心线程数
int corePoolSize = dynamicThreadPoolExecutor.getCorePoolSize();
//最大线程数
int maximumPoolSize = dynamicThreadPoolExecutor.getMaximumPoolSize();
//队列类型
String queueType = dynamicThreadPoolExecutor.getQueue().getClass().getSimpleName();
//队列初始容量
int queueCapacity = dynamicThreadPoolExecutor.getQueue().size() + dynamicThreadPoolExecutor.getQueue().remainingCapacity();
//队列剩余容量
int remainingCapacity = dynamicThreadPoolExecutor.getQueue().remainingCapacity();
//活跃线程数
int activeCount = dynamicThreadPoolExecutor.getActiveCount();
//存活时间
long keepAliveTime = dynamicThreadPoolExecutor.getKeepAliveTime(TimeUnit.MILLISECONDS);
//拒绝策略
String rejectType = dynamicThreadPoolExecutor.getRejectedExecutionHandler().getClass().getSimpleName();
//任务数
long taskCount = dynamicThreadPoolExecutor.getTaskCount();
//已完成任务数
long completeTaskCount = dynamicThreadPoolExecutor.getCompletedTaskCount();
//历史最大线程数
int largestPoolSize = dynamicThreadPoolExecutor.getLargestPoolSize();
//当前负载
String currentLoad = divide(activeCount, maximumPoolSize) + "%";
//峰值负载
String peakLoad = divide(largestPoolSize, maximumPoolSize) + "%";
//拒绝数量
long rejectCount = dynamicThreadPoolManager.getRejectCount(dynamicThreadPoolExecutor.getThreadPoolName());
log.info("线程池名称:{} " +
"当前线程数:{}, 核心线程数:{}, 最大线程数:{}, 队列类型:{}, 队列初始容量:{}, " +
"队列剩余容量:{},活跃线程数:{}, 空闲存活时间:{}ms, 拒绝策略:{}, 任务数:{}, 完成任务数:{}, " +
"历史最大线程数:{}, 当前负载:{}, 峰值负载:{}, 拒绝数量:{}",
threadPoolName, currentThreadSize, corePoolSize, maximumPoolSize, queueType, queueCapacity,
remainingCapacity, activeCount, keepAliveTime, rejectType, taskCount, completeTaskCount,
largestPoolSize, currentLoad, peakLoad, rejectCount);
});
}
}
public static int divide(int num1, int num2) {
return ((int) (Double.parseDouble(num1 + "") / Double.parseDouble(num2 + "") * 100));
}
}
到这就已经弄好动态线程池了，接下来看看有什么好处。
1、可以时刻观察业务中线程池负载情况，包括当前负载、最大负载、拒绝数量等等
2、当线上出现报警时
可以查看当前服务器负载情况，如果cpu使用率不高且load不高的话，适当调整线程池数量，最大化利用服务器资源。
如有疑问可联系：[email protected]