ScheduledExecutorService的使用及守护线程

水深无声 2024-03-31 17:59 47阅读 0赞

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只运行一次

![https://img-blog.csdnimg.cn/20201028113139387.png?x-oss-process=image/watermark,type\_ZmFuZ3poZW5naGVpdGk,shadow\_10,text\_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dhbmd4dWVsZWkwMzY=,size\_16,color\_FFFFFF,t\_70][https_img-blog.csdnimg.cn_20201028113139387.png_x-oss-process_image_watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dhbmd4dWVsZWkwMzY_size_16_color_FFFFFF_t_70]

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private static ScheduledExecutorService scheduler;

public static void main(String\[\] args) throws Exception \{

scheduler = Executors.newScheduledThreadPool(5);

// 循环任务，按照上一次任务的发起时间计算下一次任务的开始时间

scheduler.scheduleAtFixedRate(((

new Runnable() \{

@Override

public void run() \{

System.out.println(

" 开始 threadId = "

\+ Thread.currentThread().getId()

\+ ",,,threadName = " + Thread.currentThread().getName()

\+ ",,,时间" + formatDateToString(new Date())

);

try \{

Thread.sleep(3000);

System.out.println(

" 结束 threadId = "

\+ Thread.currentThread().getId()

\+ ",,,threadName = " + Thread.currentThread().getName()

\+ ",,,时间" + formatDateToString(new Date())

);

\} catch (InterruptedException e) \{

e.printStackTrace();

//模拟抛出异常

if (1 == 1) \{

throw new RuntimeException("异常");

\})),

0, 1,

TimeUnit.SECONDS);

Thread.sleep(20000);

System.out.println(

" 主线程 threadId = "

\+ Thread.currentThread().getId()

\+ ",,,threadName = " + Thread.currentThread().getName()

\+ ",,,时间" + formatDateToString(new Date())

);

public static String formatDateToString(Date time) \{

SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss");

return sdf.format(time);

![https://image.dandelioncloud.cn/pgy_files/images/2024/03/31/bdc974e4d61d45b899a068119c927fe7.png][https_img-blog.csdnimg.cn_20201028111403823.png]

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private static ScheduledExecutorService scheduler;

public static void main(String\[\] args) throws Exception \{

scheduler = Executors.newScheduledThreadPool(5);

// 循环任务，按照上一次任务的发起时间计算下一次任务的开始时间

scheduler.scheduleAtFixedRate(((

new Runnable() \{

@Override

public void run() \{

System.out.println(

" 开始 threadId = "

\+ Thread.currentThread().getId()

\+ ",,,threadName = " + Thread.currentThread().getName()

\+ ",,,时间" + formatDateToString(new Date())

);

try \{

Thread.sleep(3000);

System.out.println(

" 结束 threadId = "

\+ Thread.currentThread().getId()

\+ ",,,threadName = " + Thread.currentThread().getName()

\+ ",,,时间" + formatDateToString(new Date())

);

\} catch (InterruptedException e) \{

e.printStackTrace();

\})),

0, 1,

TimeUnit.SECONDS);

public static String formatDateToString(Date time) \{

SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss");

return sdf.format(time);

可以看到其实间隔时间已经变成了 任务执行时间来控制，但是一般来说，很少有任务执行时间超过间隔时间，但是这个知识点还是要知道。

![https://img-blog.csdnimg.cn/20201028111720513.png?x-oss-process=image/watermark,type\_ZmFuZ3poZW5naGVpdGk,shadow\_10,text\_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dhbmd4dWVsZWkwMzY=,size\_16,color\_FFFFFF,t\_70][https_img-blog.csdnimg.cn_20201028111720513.png_x-oss-process_image_watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dhbmd4dWVsZWkwMzY_size_16_color_FFFFFF_t_70]

scheduleAtFixedRate 正常使用 延迟时间1S，执行任务时间 1S，间隔时间3S

private static ScheduledExecutorService scheduler;

public static void main(String\[\] args) throws Exception \{

scheduler = Executors.newScheduledThreadPool(5);

// 循环任务，按照上一次任务的发起时间计算下一次任务的开始时间

scheduler.scheduleAtFixedRate(((

new Runnable() \{

@Override

public void run() \{

System.out.println(

" 开始 threadId = "

\+ Thread.currentThread().getId()

\+ ",,,threadName = " + Thread.currentThread().getName()

\+ ",,,时间" + formatDateToString(new Date())

);

try \{

Thread.sleep(1000);

System.out.println(

" 结束 threadId = "

\+ Thread.currentThread().getId()

\+ ",,,threadName = " + Thread.currentThread().getName()

\+ ",,,时间" + formatDateToString(new Date())

);

\} catch (InterruptedException e) \{

e.printStackTrace();

\})),

0, 3,

TimeUnit.SECONDS);

public static String formatDateToString(Date time) \{

SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss");

return sdf.format(time);

![97ce45d25ab04005911057c92e52c6a5.png][]

scheduleWithFixedDelay 正常使用

private static ScheduledExecutorService scheduler;

public static void main(String\[\] args) throws Exception \{

scheduler = Executors.newScheduledThreadPool(5);

// 循环任务，按照上一次任务的发起时间计算下一次任务的开始时间

scheduler.scheduleWithFixedDelay(((

new Runnable() \{

@Override

public void run() \{

System.out.println(

" 开始 threadId = "

\+ Thread.currentThread().getId()

\+ ",,,threadName = " + Thread.currentThread().getName()

\+ ",,,时间" + formatDateToString(new Date())

);

try \{

Thread.sleep(3000);

System.out.println(

" 结束 threadId = "

\+ Thread.currentThread().getId()

\+ ",,,threadName = " + Thread.currentThread().getName()

\+ ",,,时间" + formatDateToString(new Date())

);

\} catch (InterruptedException e) \{

e.printStackTrace();

\})),

0, 1,

TimeUnit.SECONDS);

public static String formatDateToString(Date time) \{

SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss");

return sdf.format(time);

**scheduleWithFixedDelay****以上一次任务的结束时间 + 延迟时间 = 下一次任务的开始时间。**

![https://img-blog.csdnimg.cn/20201028112216360.png?x-oss-process=image/watermark,type\_ZmFuZ3poZW5naGVpdGk,shadow\_10,text\_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dhbmd4dWVsZWkwMzY=,size\_16,color\_FFFFFF,t\_70][https_img-blog.csdnimg.cn_20201028112216360.png_x-oss-process_image_watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dhbmd4dWVsZWkwMzY_size_16_color_FFFFFF_t_70]

以上就是两个循环任务的使用

![4e2313308e3d464d9581f18f3c2094af.png][]

private static ScheduledExecutorService scheduler;

public static void main(String\[\] args) throws Exception \{

scheduler = Executors.newScheduledThreadPool(5, new ThreadFactory() \{

private AtomicInteger counter = new AtomicInteger(0);

//可以在这里对线程做一些操作

@Override

public Thread newThread(Runnable r) \{

int count = counter.incrementAndGet();

System.out.println("线程创建counter = " + count);

Thread thread = new Thread(r);

thread.setName("测试线程"+count);

return thread;

\});

System.out.println("main thread time : " + formatDateToString(new Date()));

// 循环任务，按照上一次任务的发起时间计算下一次任务的开始时间

scheduler.scheduleAtFixedRate(((

new Runnable() \{

@Override

public void run() \{

System.out.println(

" 开始 threadId = "

\+ Thread.currentThread().getId()

\+ ",,,threadName = " + Thread.currentThread().getName()

\+ ",,,时间" + formatDateToString(new Date())

);

\})),

1,5,

TimeUnit.SECONDS);

public static String formatDateToString(Date time) \{

SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss");

return sdf.format(time);

其实就是提供了一个扩展点，允许你在创建线程的时候，做一些管理或者说一些其他的操作

![https://img-blog.csdnimg.cn/20201028114539843.png?x-oss-process=image/watermark,type\_ZmFuZ3poZW5naGVpdGk,shadow\_10,text\_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dhbmd4dWVsZWkwMzY=,size\_16,color\_FFFFFF,t\_70][https_img-blog.csdnimg.cn_20201028114539843.png_x-oss-process_image_watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dhbmd4dWVsZWkwMzY_size_16_color_FFFFFF_t_70]

也可以使用 ThreadFactoryBuilder 构建类 来构建FactoryBuilder

scheduler = Executors.newScheduledThreadPool(5,new ThreadFactoryBuilder()

.setNameFormat("测试线程-%d")

// .setDaemon(true) //这个参数是设置为守护线程 也叫 服务线程

.build());

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[8093f71c1641416e96da528dcb87b89a.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/31/493dbd325ca34d0b87b8e3a71610abb2.png
[7a2bbabe629d4f0c98b5b88512a830d3.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/31/2e483bc92d8e40a69c1b7b93c6ff1bf1.png
[https_img-blog.csdnimg.cn_20201028113139387.png_x-oss-process_image_watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dhbmd4dWVsZWkwMzY_size_16_color_FFFFFF_t_70]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/31/5cd505ef864645bda567aec352c5a8bb.png
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[015f615d6bcf4c759b1a16386dfa959e.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/31/e791d0ec79ad47f78c2b145504d862f9.png
[https_img-blog.csdnimg.cn_20201028111403823.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/31/bdc974e4d61d45b899a068119c927fe7.png
[2b185d6ce018434380d220694239fceb.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/31/db59568c5c0246539f0831180f65e8a3.png
[https_img-blog.csdnimg.cn_20201028111720513.png_x-oss-process_image_watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dhbmd4dWVsZWkwMzY_size_16_color_FFFFFF_t_70]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/31/b5261af93a3c4611be89847ab0396a05.png
[97ce45d25ab04005911057c92e52c6a5.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/31/50f9d394c164438f9615d324cd909fa8.png
[https_img-blog.csdnimg.cn_20201028112216360.png_x-oss-process_image_watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dhbmd4dWVsZWkwMzY_size_16_color_FFFFFF_t_70]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/31/cdc5dbf8e1f74a75924a40ad5d631bde.png
[4e2313308e3d464d9581f18f3c2094af.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/31/740110156266497082fe0bda16015b5a.png
[https_img-blog.csdnimg.cn_20201028114539843.png_x-oss-process_image_watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dhbmd4dWVsZWkwMzY_size_16_color_FFFFFF_t_70]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/31/3ed39e6a04cc41cf8890e6b2389b598c.png
[a5fe64c4bef54054861b1d4e1f4e6dd9.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/31/62a5c38bf7744e55a740625cf8bad3ba.png