[java: Cleaner]-一文述之

Cleaner

Cleaner 是 Java 9 引入的资源清理机制，用于在对象被垃圾回收后自动或手动执行清理操作，替代 finalize()，安全、异步且高效。

public final class Cleaner {final CleanerImpl impl;static {CleanerImpl.setCleanerImplAccess(new Function<Cleaner, CleanerImpl>() {@Overridepublic CleanerImpl apply(Cleaner cleaner) {return cleaner.impl;}});}private Cleaner() {impl = new CleanerImpl();}// 创建一个新的 Cleaner，使用默认后台守护线程处理清理任务。public static Cleaner create() {Cleaner cleaner = new Cleaner();cleaner.impl.start(cleaner, null);return cleaner;}// 使用指定线程工厂创建 Cleaner，适合自定义线程配置（如优先级、命名）。public static Cleaner create(ThreadFactory threadFactory) {Objects.requireNonNull(threadFactory, "threadFactory");Cleaner cleaner = new Cleaner();cleaner.impl.start(cleaner, threadFactory);return cleaner;}// 注册一个对象与清理任务，当对象被 GC 回收后，后台线程执行 action。返回 Cleanable 可用于提前清理。public Cleanable register(Object obj, Runnable action) {Objects.requireNonNull(obj, "obj");Objects.requireNonNull(action, "action");return new CleanerImpl.PhantomCleanableRef(obj, this, action);}// 表示一次清理任务，调用 clean() 方法可以手动执行清理逻辑，只会执行一次。public interface Cleanable {void clean();}}