!457 HashMap应指定初始长度，增加CompletableFuture相关封装

Merge pull request !457 from 阿超/v5-dev

hutool-core/src/test/java/cn/hutool/core/thread/SyncUtilTest.java

@@ -0,0 +1,36 @@
+package cn.hutool.core.thread;
+
+import cn.hutool.core.lang.Assert;
+import org.junit.Test;
+
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * CompletableFuture工具类测试
+ *
+ * @author <achao1441470436@gmail.com>
+ * @since 2021/11/10 0010 21:15
+ */
+public class SyncUtilTest {
+
+	@Test
+	public void waitAndGetTest() {
+		CompletableFuture<String> hutool = CompletableFuture.supplyAsync(() -> {
+			ThreadUtil.sleep(3, TimeUnit.SECONDS);
+			return "hutool";
+		});
+		CompletableFuture<String> sweater = CompletableFuture.supplyAsync(() -> {
+			ThreadUtil.sleep(4, TimeUnit.SECONDS);
+			return "卫衣";
+		});
+		CompletableFuture<String> warm = CompletableFuture.supplyAsync(() -> {
+			ThreadUtil.sleep(5, TimeUnit.SECONDS);
+			return "真暖和";
+		});
+		// 等待完成
+		SyncUtil.wait(hutool, sweater, warm);
+		// 获取结果
+		Assert.isTrue("hutool卫衣真暖和".equals(SyncUtil.get(hutool) + SyncUtil.get(sweater) + SyncUtil.get(warm)));
+	}
+}