BlockingQueue四组API

HeJin大约 3 分钟JavaJUC并发编程

方式	抛出异常	不会抛出异常，有返回值	阻塞一直等待	超时等待
添加	add(E e)	offer(E e)	put(E e)	offer(, ,)
移除	remove()	poll()	take()	pull(,)
检测队首元素	element	peek	-	-

1、抛出异常

add添加元素

/**
 * 抛出异常
 */
public static void test1(){
    // 队列的大小
    ArrayBlockingQueue blockingQueue = new ArrayBlockingQueue<>(3);

    System.out.println(blockingQueue.add("a"));
    System.out.println(blockingQueue.add("b"));
    System.out.println(blockingQueue.add("c"));
    // 队列已经满了： Queue full异常
    System.out.println(blockingQueue.add("d"));

}

结果：

true
true
true
Exception in thread "main" java.lang.IllegalStateException: Queue full
	at java.util.AbstractQueue.add(AbstractQueue.java:98)
	at java.util.concurrent.ArrayBlockingQueue.add(ArrayBlockingQueue.java:312)
	at com.hejin.bq.Test.test1(Test.java:27)
	at com.hejin.bq.Test.main(Test.java:13)

Process finished with exit code 1

remove弹出元素

public static void test1(){
    // 队列的大小
    ArrayBlockingQueue blockingQueue = new ArrayBlockingQueue<>(3);

    System.out.println(blockingQueue.add("a"));
    System.out.println(blockingQueue.add("b"));
    System.out.println(blockingQueue.add("c"));

    System.out.println(blockingQueue.remove());
    System.out.println(blockingQueue.remove());
    System.out.println(blockingQueue.remove());
}

结果：

true
true
true
a
b
c

Process finished with exit code 0

队列为空

public static void test1(){
    // 队列的大小
    ArrayBlockingQueue blockingQueue = new ArrayBlockingQueue<>(3);

    System.out.println(blockingQueue.add("a"));
    System.out.println(blockingQueue.add("b"));
    System.out.println(blockingQueue.add("c"));

    System.out.println(blockingQueue.remove());
    System.out.println(blockingQueue.remove());
    System.out.println(blockingQueue.remove());

    // 队列已空：java.util.NoSuchElementException
    System.out.println(blockingQueue.remove());
}

结果：

true
true
true
a
b
c
Exception in thread "main" java.util.NoSuchElementException
	at java.util.AbstractQueue.remove(AbstractQueue.java:117)
	at com.hejin.bq.Test.test1(Test.java:32)
	at com.hejin.bq.Test.main(Test.java:13)

Process finished with exit code 1

element队首元素

public static void test1(){
    // 队列的大小
    ArrayBlockingQueue blockingQueue = new ArrayBlockingQueue<>(3);

    System.out.println(blockingQueue.add("a"));
    System.out.println(blockingQueue.add("b"));
    System.out.println(blockingQueue.add("c"));

    System.out.println("队首："+blockingQueue.element());

    System.out.println(blockingQueue.remove());
    System.out.println("队首："+blockingQueue.element());
    System.out.println(blockingQueue.remove());
    System.out.println(blockingQueue.remove());

    // 队列已空
    System.out.println("队首："+blockingQueue.element());
}

结果：

true
true
true
队首：a
a
队首：b
b
c
Exception in thread "main" java.util.NoSuchElementException
	at java.util.AbstractQueue.element(AbstractQueue.java:136)
	at com.hejin.bq.Test.test1(Test.java:35)
	at com.hejin.bq.Test.main(Test.java:13)

Process finished with exit code 1

2、有返回值，不抛出异常

offer添加

/**
 * 有返回值，不抛出异常
 */
public static void test2(){
    ArrayBlockingQueue blockingQueue = new ArrayBlockingQueue<>(3);

    System.out.println(blockingQueue.offer("a"));
    System.out.println(blockingQueue.offer("b"));
    System.out.println(blockingQueue.offer("c"));
    // 不抛出异常，返回false
    System.out.println(blockingQueue.offer("d"));
}

结果：

true
true
true
false

Process finished with exit code 0

poll弹出

public static void test2(){
    ArrayBlockingQueue blockingQueue = new ArrayBlockingQueue<>(3);

    System.out.println(blockingQueue.offer("a"));
    System.out.println(blockingQueue.offer("b"));
    System.out.println(blockingQueue.offer("c"));

    System.out.println(blockingQueue.poll());
    System.out.println(blockingQueue.poll());
    System.out.println(blockingQueue.poll());
    // 队列已空。返回null
    System.out.println(blockingQueue.poll());
}

结果：

true
true
true
a
b
c
null

Process finished with exit code 0

peek队首元素

public static void test2(){
    ArrayBlockingQueue blockingQueue = new ArrayBlockingQueue<>(3);

    System.out.println(blockingQueue.offer("a"));
    System.out.println(blockingQueue.offer("b"));
    System.out.println(blockingQueue.offer("c"));

    // 查看队首元素
    System.out.println("队首："+blockingQueue.peek());

    System.out.println(blockingQueue.poll());
    System.out.println("队首："+blockingQueue.peek());
    System.out.println(blockingQueue.poll());
    System.out.println(blockingQueue.poll());
    // 队列已空。返回null
    System.out.println("队首："+blockingQueue.peek());
}

结果：

true
true
true
队首：a
a
队首：b
b
c
队首：null

Process finished with exit code 0

3、等待，一直阻塞

put添加元素

public class Test {
    public static void main(String[] args) throws InterruptedException {
        test3();
    }

    /**
     * 等待,阻塞（一直阻塞）
     */
    public static void test3() throws InterruptedException {
        ArrayBlockingQueue blockingQueue = new ArrayBlockingQueue<>(3);

        blockingQueue.put("a");
        blockingQueue.put("b");
        blockingQueue.put("c");
        // 队列已满。一直等待
        blockingQueue.put("d");
    }
}

结果：程序一直等待。

take取出元素

public static void test3() throws InterruptedException {
    ArrayBlockingQueue blockingQueue = new ArrayBlockingQueue<>(3);

    blockingQueue.put("a");
    blockingQueue.put("b");
    blockingQueue.put("c");

    System.out.println(blockingQueue.take());
    System.out.println(blockingQueue.take());
    System.out.println(blockingQueue.take());
    // 队列已空：一直等待
    System.out.println(blockingQueue.take());
}

队列中的元素取完之后，一直等待。

4、等待，超时退出

offer 超时等待添加元素

/**
 * 等待,阻塞（等待超时）
 */
public static void test4() throws InterruptedException {
    ArrayBlockingQueue blockingQueue = new ArrayBlockingQueue<>(3);

    blockingQueue.offer("a");
    blockingQueue.offer("b");
    blockingQueue.offer("c");
    // 队列已满。等待2秒，之后超时退出
    blockingQueue.offer("d",2, TimeUnit.SECONDS);
}

等了2秒之后，程序结束。

Process finished with exit code 0

pull 超时等待弹出元素

public static void test4() throws InterruptedException {
    ArrayBlockingQueue blockingQueue = new ArrayBlockingQueue<>(3);

    blockingQueue.offer("a");
    blockingQueue.offer("b");
    blockingQueue.offer("c");
    // 队列已满。等待2秒，之后超时退出
    blockingQueue.offer("d",2, TimeUnit.SECONDS);
    System.out.println("====================");
    System.out.println(blockingQueue.poll());
    System.out.println(blockingQueue.poll());
    System.out.println(blockingQueue.poll());
    // 队列已空：等待2秒，超时退出
    System.out.println(blockingQueue.poll(2,TimeUnit.SECONDS));
}

结果：

====================
a
b
c
null

Process finished with exit code 0

BlockingQueue四组API

#

# 1、抛出异常

# 2、有返回值，不抛出异常

# 3、等待，一直阻塞

# 4、等待 ，超时退出

1、抛出异常

2、有返回值，不抛出异常

3、等待，一直阻塞

4、等待，超时退出