线程基础、原子类

src/main/java/xyz/xuminghai/atomic/AtomicIntegerArrayDemo.java

@@ -0,0 +1,79 @@
+package xyz.xuminghai.atomic;
+
+import java.util.concurrent.atomic.AtomicIntegerArray;
+
+/**
+ * 2023/3/13 17:30 星期一<br/>
+ *
+ * <h1>AtomicIntegerArray示例</h1>
+ * 可以看做是一组AtomicInteger
+ *
+ * @author xuMingHai
+ */
+public class AtomicIntegerArrayDemo {
+
+	private static final AtomicIntegerArray ATOMIC_INTEGER_ARRAY = new AtomicIntegerArray(3);
+
+	public static void main(String[] args) {
+		Thread t1 = new Thread(() -> {
+			for (int i = 0; i < 300; i++) {
+				if ((i % 2) == 0) {
+					ATOMIC_INTEGER_ARRAY.getAndIncrement(1);
+				}
+				else if ((i % 3) == 0) {
+					ATOMIC_INTEGER_ARRAY.getAndIncrement(2);
+				}
+				else {
+					ATOMIC_INTEGER_ARRAY.getAndIncrement(0);
+				}
+			}
+
+		}, "t1");
+
+		Thread t2 = new Thread(() -> {
+			for (int i = 0; i < 200; i++) {
+				if ((i % 2) == 0) {
+					ATOMIC_INTEGER_ARRAY.getAndDecrement(1);
+				}
+				else if ((i % 3) == 0) {
+					ATOMIC_INTEGER_ARRAY.getAndDecrement(2);
+				}
+				else {
+					ATOMIC_INTEGER_ARRAY.getAndDecrement(0);
+				}
+			}
+
+		}, "t2");
+
+		Thread t3 = new Thread(() -> {
+			for (int i = 0; i < 100; i++) {
+				if ((i % 2) == 0) {
+					ATOMIC_INTEGER_ARRAY.getAndDecrement(1);
+				}
+				else if ((i % 3) == 0) {
+					ATOMIC_INTEGER_ARRAY.getAndDecrement(2);
+				}
+				else {
+					ATOMIC_INTEGER_ARRAY.getAndDecrement(0);
+				}
+			}
+
+		}, "t3");
+
+		t1.start();
+		t2.start();
+		t3.start();
+
+		try {
+			t1.join();
+			t2.join();
+			t3.join();
+		}
+		catch (InterruptedException e) {
+			throw new RuntimeException(e);
+		}
+
+		System.out.println(ATOMIC_INTEGER_ARRAY);
+	}
+
+}

src/main/java/xyz/xuminghai/atomic/AtomicIntegerFieldUpdateDemo.java

@@ -0,0 +1,56 @@
+package xyz.xuminghai.atomic;
+
+import java.util.StringJoiner;
+import java.util.concurrent.atomic.AtomicIntegerFieldUpdater;
+
+/**
+ * 2023/3/14 14:07 星期二<br/>
+ *
+ * <h1>AtomicIntegerFieldUpdater示例</h1>
+ * 根据 Java 语言访问控制，调用者无法访问该字段，则出现基于反射的嵌套异常
+ *
+ * @author xuMingHai
+ */
+public class AtomicIntegerFieldUpdateDemo {
+
+	public static void main(String[] args) {
+
+		final AtomicIntegerFieldUpdater<VolatileInteger> fieldUpdater = AtomicIntegerFieldUpdater
+				.newUpdater(VolatileInteger.class, "i");
+		final VolatileInteger volatileInteger = new VolatileInteger();
+
+		Thread t1 = new Thread(() -> fieldUpdater.getAndIncrement(volatileInteger), "t1");
+
+		Thread t2 = new Thread(() -> fieldUpdater.getAndDecrement(volatileInteger), "t2");
+
+		Thread t3 = new Thread(() -> fieldUpdater.getAndIncrement(volatileInteger), "t3");
+
+		t1.start();
+		t2.start();
+		t3.start();
+
+		try {
+			t1.join();
+			t2.join();
+			t3.join();
+		}
+		catch (InterruptedException e) {
+			throw new RuntimeException(e);
+		}
+
+		System.out.println(volatileInteger);
+
+	}
+
+}
+
+class VolatileInteger {
+	volatile int i;
+
+	@Override
+	public String toString() {
+		return new StringJoiner(", ", VolatileInteger.class.getSimpleName() + "[", "]")
+				.add("i=" + i)
+				.toString();
+	}
+}

src/main/java/xyz/xuminghai/base/InheritableThreadLocalDemo.java

@@ -0,0 +1,36 @@
+package xyz.xuminghai.base;
+
+/**
+ * 2023/3/15 23:51 星期三<br/>
+ *
+ * <h1>可继承的本地变量</h1>
+ * 适用于父线程创建子线程（由父线程创建的线程）时传递线程局部变量
+ * <p color = "red">注意子线程只是创建时局部变量来自父线程，也是完全独立的副本，不会跟随父线程的局部变量变化而变化</p>
+ *
+ * @author xuMingHai
+ */
+public class InheritableThreadLocalDemo {
+
+	private static final ThreadLocal<String> THREAD_LOCAL = new InheritableThreadLocal<String>() {
+		@Override
+		protected String initialValue() {
+			return "张三";
+		}
+	};
+
+	public static void main(String[] args) throws InterruptedException {
+
+		Thread t1 = new Thread(() -> System.out.println(Thread.currentThread().getName() + "：THREAD_LOCAL = " + THREAD_LOCAL.get()), "t1");
+		t1.start();
+		t1.join();
+
+		System.out.println(Thread.currentThread().getName() + "：THREAD_LOCAL = " + THREAD_LOCAL.get());
+
+		THREAD_LOCAL.set("李四");
+		Thread t2 = new Thread(() -> System.out.println(Thread.currentThread().getName() + "：THREAD_LOCAL = " + THREAD_LOCAL.get()), "t2");
+		t2.start();
+		System.out.println(Thread.currentThread().getName() + "：THREAD_LOCAL = " + THREAD_LOCAL.get());
+
+	}
+
+}

src/main/java/xyz/xuminghai/base/ThreadLocalDemo.java

@@ -0,0 +1,41 @@
+package xyz.xuminghai.base;
+
+/**
+ * 2023/3/15 23:34 星期三<br/>
+ *
+ * <h1>线程局部变量示例</h1>
+ * 每个线程都存在这个变量的副本，每个线程都只使用自己的ThreadLocalMap维护变量，key为ThreadLocal，value为变量
+ *
+ * @author xuMingHai
+ */
+public class ThreadLocalDemo {
+
+	/**
+	 * 使用类变量，可以避免不必要的弱引用清除key
+	 */
+	private static final ThreadLocal<Integer> THREAD_LOCAL = ThreadLocal.withInitial(() -> 0);
+
+	public static void main(String[] args) {
+
+		new Thread(() -> {
+			System.out.println(Thread.currentThread().getName() + "：THREAD_LOCAL = " + THREAD_LOCAL.get());
+			THREAD_LOCAL.set(1);
+			System.out.println(Thread.currentThread().getName() + "：THREAD_LOCAL = " + THREAD_LOCAL.get());
+		}, "t1").start();
+
+		new Thread(() -> {
+			System.out.println(Thread.currentThread().getName() + "：THREAD_LOCAL = " + THREAD_LOCAL.get());
+			THREAD_LOCAL.set(2);
+			System.out.println(Thread.currentThread().getName() + "：THREAD_LOCAL = " + THREAD_LOCAL.get());
+		}, "t2").start();
+
+		new Thread(() -> {
+			System.out.println(Thread.currentThread().getName() + "：THREAD_LOCAL = " + THREAD_LOCAL.get());
+			THREAD_LOCAL.set(3);
+			System.out.println(Thread.currentThread().getName() + "：THREAD_LOCAL = " + THREAD_LOCAL.get());
+		}, "t3").start();
+
+		System.out.println(Thread.currentThread().getName() + "：THREAD_LOCAL = " + THREAD_LOCAL.get());
+	}
+
+}

src/main/java/xyz/xuminghai/base/ThreadStackDemo.java

@@ -0,0 +1,40 @@
+package xyz.xuminghai.base;
+
+import java.util.Arrays;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * 2023/3/15 21:19 星期三<br/>
+ *
+ * <h1>线程栈信息</h1>
+ *
+ * @author xuMingHai
+ */
+public class ThreadStackDemo {
+
+	public static void main(String[] args) {
+		Thread t1 = new Thread(() -> {
+			List<String> list = new LinkedList<>();
+			list.add("");
+			try {
+				TimeUnit.SECONDS.sleep(1);
+			}
+			catch (InterruptedException e) {
+				throw new RuntimeException(e);
+			}
+			list.add("1");
+			System.out.println("list = " + list);
+			list.clear();
+		}, "t1");
+
+		t1.start();
+
+		// 直到线程死亡停止循环
+		while (t1.isAlive()) {
+			System.out.println(Arrays.toString(t1.getStackTrace()));
+		}
+	}
+
+}

src/main/java/xyz/xuminghai/base/ThreadUncaughtExceptionDemo.java

@@ -0,0 +1,34 @@
+package xyz.xuminghai.base;
+
+import java.util.concurrent.TimeUnit;
+
+/**
+ * 2023/3/15 21:45 星期三<br/>
+ *
+ * <h1>线程未捕获异常示例</h1>
+ *
+ * @author xuMingHai
+ */
+public class ThreadUncaughtExceptionDemo {
+
+	public static void main(String[] args) {
+
+		Thread t1 = new Thread(() -> {
+			throw new IllegalStateException();
+		}, "t1");
+
+		// 设置线程因为未捕获的异常导致线程终止处理器
+		t1.setUncaughtExceptionHandler((t, e) -> System.out.println(t.getName() + "：出现异常了"));
+
+		t1.start();
+
+		try {
+			TimeUnit.SECONDS.sleep(3);
+		}
+		catch (InterruptedException e) {
+			throw new RuntimeException(e);
+		}
+
+	}
+
+}