台州遭特斯拉撞擊交警 1 人犧牲，警方正依法依規進行調查、肇事車輛檢驗鑑定等
阿新 • • 發佈：2021-05-18
1.要求用執行緒順序列印A1B2C3....Z26
寫法1，使用LockSupport完成
public class T02_00_LockSupport { static Thread t1 = null, t2 = null; public static void main(String[] args) throws Exception { char[] aI = "1234567".toCharArray(); char[] aC = "ABCDEFG".toCharArray(); t1 = new Thread(() -> {for (char c : aI) { System.out.print(c); LockSupport.unpark(t2); //叫醒T2 LockSupport.park(); //T1阻塞 當前執行緒阻塞 } }, "t1"); t2 = new Thread(() -> { for (char c : aC) { LockSupport.park(); //t2掛起 System.out.print(c); LockSupport.unpark(t1); //叫醒t1 } }, "t2"); t1.start(); t2.start(); } }
寫法二：使用syschronized完成，其中countDownLatch和開頭定義的boolean變數是兩種讓那個執行緒先列印的方式
public class T07_00_sync_wait_notify { //private static volatile boolean t2Started = false; privatestatic CountDownLatch latch = new CountDownLatch(1); public static void main(String[] args) { final Object o = new Object(); char[] aI = "1234567".toCharArray(); char[] aC = "ABCDEFG".toCharArray(); new Thread(() -> { try { latch.await(); } catch (InterruptedException e) { e.printStackTrace(); } synchronized (o) { // while(!t2Started) { // try { // o.wait(); // } catch (InterruptedException e) { // e.printStackTrace(); // } // } for (char c : aI) { System.out.print(c); try { o.notify(); o.wait(); } catch (InterruptedException e) { e.printStackTrace(); } } o.notify(); } }, "t1").start(); new Thread(() -> { synchronized (o) { for (char c : aC) { System.out.print(c); latch.countDown(); //t2Started = true; try { o.notify(); o.wait(); } catch (InterruptedException e) { e.printStackTrace(); } } o.notify(); } }, "t2").start(); } }
寫法三：lock鎖實現方式
public class ThreadTask{ public static void main(String[] args) { char[] aI = "1234567".toCharArray(); char[] aC = "ABCDEFG".toCharArray(); Lock lock = new ReentrantLock(); Condition condition = lock.newCondition(); new Thread(() -> { try { lock.lock(); for (char c : aI) { System.out.print(c); condition.signal(); condition.await(); } condition.signal(); /**為了防止最後有執行緒被鎖住*/ } catch (Exception e) { e.printStackTrace(); } finally { lock.unlock(); } }, "t1").start(); new Thread(() -> { try { lock.lock(); //synchronized for (char c : aC) { System.out.print(c); condition.signal(); //o.notify condition.await(); //o.wait } condition.signal(); } catch (Exception e) { e.printStackTrace(); } finally { lock.unlock(); } }, "t2").start(); } }
lock鎖的兩個等待執行緒佇列實現：
public class T09_00_lock_condition { public static void main(String[] args) { char[] aI = "1234567".toCharArray(); char[] aC = "ABCDEFG".toCharArray(); Lock lock = new ReentrantLock(); Condition conditionT1 = lock.newCondition(); //佇列 Condition conditionT2 = lock.newCondition(); CountDownLatch latch = new CountDownLatch(1); new Thread(() -> { try { latch.await(); } catch (InterruptedException e) { e.printStackTrace(); } lock.lock(); try { for (char c : aI) { System.out.print(c); conditionT2.signal(); conditionT1.await(); } conditionT2.signal(); } catch (Exception e) { e.printStackTrace(); } finally { lock.unlock(); } }, "t1").start(); new Thread(() -> { lock.lock(); try { for (char c : aC) { System.out.print(c); latch.countDown(); conditionT1.signal(); conditionT2.await(); } conditionT1.signal(); } catch (Exception e) { e.printStackTrace(); } finally { lock.unlock(); } }, "t2").start(); } }
寫法四：TransferQuery實現
public class T13_TransferQueue { public static void main(String[] args) { char[] aI = "1234567".toCharArray(); char[] aC = "ABCDEFG".toCharArray(); TransferQueue<Character> queue = new LinkedTransferQueue<Character>(); new Thread(() -> { try { for (char c : aI) { System.out.print(queue.take());//如果佇列中沒有值，就會阻塞，等待佇列中有值之後才往下執行 queue.transfer(c);//向佇列中新增值 } } catch (InterruptedException e) { e.printStackTrace(); } }, "t1").start(); new Thread(() -> { try { for (char c : aC) { queue.transfer(c); System.out.print(queue.take()); } } catch (InterruptedException e) { e.printStackTrace(); } }, "t2").start(); } }
寫法五：使用阻塞佇列完成
public class T04_00_BlockingQueue { static BlockingQueue<String> q1 = new ArrayBlockingQueue(1); static BlockingQueue<String> q2 = new ArrayBlockingQueue(1); public static void main(String[] args) throws Exception { char[] aI = "1234567".toCharArray(); char[] aC = "ABCDEFG".toCharArray(); new Thread(() -> { for (char c : aI) { System.out.print(c); try { q1.put("ok"); q2.take(); } catch (InterruptedException e) { e.printStackTrace(); } } }, "t1").start(); new Thread(() -> { for (char c : aC) { try { q1.take(); } catch (InterruptedException e) { e.printStackTrace(); } System.out.print(c); try { q2.put("ok"); } catch (InterruptedException e) { e.printStackTrace(); } } }, "t2").start(); } }
寫法六：使用cas方式完成
public class T03_00_cas { enum ReadyToRun {T1, T2} static volatile ReadyToRun r = ReadyToRun.T1; //思考為什麼必須volatile public static void main(String[] args) { char[] aI = "1234567".toCharArray(); char[] aC = "ABCDEFG".toCharArray(); new Thread(() -> { for (char c : aI) { while (r != ReadyToRun.T1) { } System.out.print(c); r = ReadyToRun.T2; } }, "t1").start(); new Thread(() -> { for (char c : aC) { while (r != ReadyToRun.T2) { } System.out.print(c); r = ReadyToRun.T1; } }, "t2").start(); } }
寫法七，使用AtomicInteger完成，和自旋鎖相似
public class T05_00_AtomicInteger { static AtomicInteger threadNo = new AtomicInteger(1); public static void main(String[] args) { char[] aI = "1234567".toCharArray(); char[] aC = "ABCDEFG".toCharArray(); new Thread(() -> { for (char c : aI) { while (threadNo.get() != 1) { } System.out.print(c); threadNo.set(2); } }, "t1").start(); new Thread(() -> { for (char c : aC) { while (threadNo.get() != 2) { } System.out.print(c); threadNo.set(1); } }, "t2").start(); } }