java中的线程几种状态

╰半橙微兮° 2022-10-11 01:18 192阅读 0赞

/**
 * A thread state. A thread can be in one of the following states:
 * <ul>
 * <li>{@link #NEW} 
 * A thread that has not yet started is in this state.
 * </li>
 * <li>{@link #RUNNABLE} 
 * A thread executing in the Java virtual machine is in this state.
 * </li>
 * <li>{@link #BLOCKED} 
 * A thread that is blocked waiting for a monitor lock
 * is in this state.
 * </li>
 * <li>{@link #WAITING} 
 * A thread that is waiting indefinitely for another thread to
 * perform a particular action is in this state.
 * </li>
 * <li>{@link #TIMED_WAITING} 
 * A thread that is waiting for another thread to perform an action
 * for up to a specified waiting time is in this state.
 * </li>
 * <li>{@link #TERMINATED} 
 * A thread that has exited is in this state.
 * </li>
 * </ul>
 *
 * 
 * A thread can be in only one state at a given point in time.
 * These states are virtual machine states which do not reflect
 * any operating system thread states.
 *
 * @since 1.5
 * @see #getState
 */
 public enum State {
 /**
 * Thread state for a thread which has not yet started.
 */
 NEW,
 
 /**
 * Thread state for a runnable thread. A thread in the runnable
 * state is executing in the Java virtual machine but it may
 * be waiting for other resources from the operating system
 * such as processor.
 */
 RUNNABLE,
 
 /**
 * Thread state for a thread blocked waiting for a monitor lock.
 * A thread in the blocked state is waiting for a monitor lock
 * to enter a synchronized block/method or
 * reenter a synchronized block/method after calling
 * {@link Object#wait() Object.wait}.
 */
 BLOCKED,
 
 /**
 * Thread state for a waiting thread.
 * A thread is in the waiting state due to calling one of the
 * following methods:
 * <ul>
 * <li>{@link Object#wait() Object.wait} with no timeout</li>
 * <li>{@link #join() Thread.join} with no timeout</li>
 * <li>{@link LockSupport#park() LockSupport.park}</li>
 * </ul>
 *
 * A thread in the waiting state is waiting for another thread to
 * perform a particular action.
 *
 * For example, a thread that has called <tt>Object.wait()</tt>
 * on an object is waiting for another thread to call
 * <tt>Object.notify()</tt> or <tt>Object.notifyAll()</tt> on
 * that object. A thread that has called <tt>Thread.join()</tt>
 * is waiting for a specified thread to terminate.
 */
 WAITING,
 
 /**
 * Thread state for a waiting thread with a specified waiting time.
 * A thread is in the timed waiting state due to calling one of
 * the following methods with a specified positive waiting time:
 * <ul>
 * <li>{@link #sleep Thread.sleep}</li>
 * <li>{@link Object#wait(long) Object.wait} with timeout</li>
 * <li>{@link #join(long) Thread.join} with timeout</li>
 * <li>{@link LockSupport#parkNanos LockSupport.parkNanos}</li>
 * <li>{@link LockSupport#parkUntil LockSupport.parkUntil}</li>
 * </ul>
 */
 TIMED_WAITING,
 
 /**
 * Thread state for a terminated thread.
 * The thread has completed execution.
 */
 TERMINATED;
 }

一共有六种

1.NEW

就是新建状态，此时还没有运行start方法

2.RUNNABLE

这个包含就绪和运行状态

3.BLOCKED

阻塞状态，就是在进入synchronized代码块时，等待Object monitor时会处于这个状态

4.WAITING

等待状态,例如wait,join,LockSupport.park会进入该状态，需要配套的notify/notifyAll/terminate,unPark才会出来

5.TIMED\_WAITING

超时等待. 例如sleep(),wait(),LockSupport.parkNanos()

6.TERMINATE