commit ComletableFuture example

Fadezed · Fadezed · commit 23baad724ec9 · 2019-07-03T14:35:37.000+08:00
diff --git a/src/main/java/com/example/concurrency/features/completablefuture/CompletableFutureExample.java b/src/main/java/com/example/concurrency/features/completablefuture/CompletableFutureExample.java
@@ -0,0 +1,116 @@
+package com.example.concurrency.features.completablefuture;
+
+import com.example.concurrency.util.ThreadUtil;
+
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * 描述:
+ * CompletableFutureExample  Java 8 异步编程可描述串行关系、AND汇聚关系和OR汇聚关系以及异常处理
+ *
+ * @author zed
+ * @since 2019-07-03 1:57 PM
+ */
+public class CompletableFutureExample {
+    /**
+     * 任务 1：洗水壶 -> 烧开水
+     */
+    private CompletableFuture<Void> f1 = CompletableFuture.runAsync(()->{
+                System.out.println("T1: 洗水壶...");
+                ThreadUtil.sleep(1, TimeUnit.SECONDS);
+                System.out.println("T1: 烧开水...");
+                ThreadUtil.sleep(15, TimeUnit.SECONDS);
+    });
+    /**
+     * 任务 2：洗茶壶 -> 洗茶杯 -> 拿茶叶
+     */
+    private CompletableFuture<String> f2 = CompletableFuture.supplyAsync(()->{
+                System.out.println("T2: 洗茶壶...");
+                ThreadUtil.sleep(1, TimeUnit.SECONDS);
+
+                System.out.println("T2: 洗茶杯...");
+                ThreadUtil.sleep(2, TimeUnit.SECONDS);
+
+                System.out.println("T2: 拿茶叶...");
+                ThreadUtil.sleep(1, TimeUnit.SECONDS);
+                return " 龙井 ";
+    });
+    /**
+     * 任务 3：任务 1 和任务 2 完成后执行：泡茶
+     */
+    private CompletableFuture<String> f3 = f1.thenCombine(f2, (e, tf)->{
+                System.out.println("T1: 拿到茶叶:" + tf);
+                System.out.println("T1: 泡茶...");
+                return " 上茶:" + tf;
+    });
+
+
+    public static void main(String[] args) {
+        CompletableFutureExample example = new CompletableFutureExample();
+        System.out.println(example.f3.join());
+    }
+
+    /**
+     * 描述串行关系 thenApply
+     */
+    static class SerialRelation{
+        private static CompletableFuture<String> f0 =
+                CompletableFuture.supplyAsync(
+                        () -> "Hello World")      //①
+                        .thenApply(s -> s + " QQ")  //②
+                        .thenApply(String::toUpperCase);//③
+
+        public static void main(String[] args) {
+            System.out.println(SerialRelation.f0.join());
+        }
+    }
+    /**
+     * 描述汇聚Or关系 thenApply
+     */
+    static class ConvergeRelation{
+        static CompletableFuture<String> f1 =
+                CompletableFuture.supplyAsync(()->{
+                    int t = getRandom(5, 10);
+                    ThreadUtil.sleep(t, TimeUnit.SECONDS);
+                    return String.valueOf(t);
+                });
+
+        static CompletableFuture<String> f2 =
+                CompletableFuture.supplyAsync(()->{
+                    int t = getRandom(5, 10);
+                    ThreadUtil.sleep(t, TimeUnit.SECONDS);
+                    return String.valueOf(t);
+                });
+
+        static CompletableFuture<String> f3 =
+                f1.applyToEither(f2,s -> s);
+
+
+        private static int getRandom(int i,int j){
+            return (int) (Math.random() * (j - i)) +i;
+        }
+        public static void main(String[] args) {
+
+            System.out.println(ConvergeRelation.f3.join());
+        }
+    }
+
+    /**
+     * 处理异常 此例为发生异常默认为0
+     */
+    static class ExceptionHandler{
+        private static CompletableFuture<Integer>
+                f0 = CompletableFuture
+                .supplyAsync(()->7/0)
+                .thenApply(r->r*10)
+                .exceptionally(e->0);
+
+        public static void main(String[] args) {
+            System.out.println(ExceptionHandler.f0.join());
+        }
+
+    }
+
+}
+
