day13

shy-coder · shy-coder · commit 6d17a2483555 · 2020-11-01T22:27:53.000+08:00
diff --git a/src/main/java/com/shy/day13/TestCalendar.java b/src/main/java/com/shy/day13/TestCalendar.java
@@ -0,0 +1,36 @@
+package com.shy.day13;
+
+import java.util.Calendar;
+import java.util.Date;
+
+/**
+ * @ClassName TestCalendar
+ * @Author shy
+ * @Date 2020/11/1
+ **/
+public class TestCalendar {
+    public static void main(String[] args) {
+        //创建Calendar对象
+        Calendar cal = Calendar.getInstance();
+        int year = cal.get(Calendar.YEAR);
+        int month = cal.get(Calendar.MONTH) + 1;
+        int dayOfMonth = cal.get(Calendar.DAY_OF_MONTH);
+        System.out.println(year + "年" + month + "月" + dayOfMonth + "日");
+
+        Calendar cal1 = Calendar.getInstance();
+        cal1.set(Calendar.YEAR,2020);
+        System.out.println(year + "年" + month + "月" + dayOfMonth + "日");
+
+        Calendar cal2 = Calendar.getInstance();
+        System.out.println(year + "年" + month + "月" + dayOfMonth + "日");
+        //加2天
+        cal2.add(Calendar.DAY_OF_MONTH,2);
+        //减3年
+        cal2.add(Calendar.YEAR,-3);
+        System.out.println(year + "年" + month + "月" + dayOfMonth + "日");
+
+        Calendar cal3 = Calendar.getInstance();
+        Date date = cal3.getTime();
+        System.out.println(date);
+    }
+}
diff --git a/src/main/java/com/shy/day13/TestSystem.java b/src/main/java/com/shy/day13/TestSystem.java
@@ -0,0 +1,22 @@
+package com.shy.day13;
+
+/**
+ * @ClassName TestSystem
+ * @Author shy
+ * @Date 2020/11/1
+ **/
+public class TestSystem {
+    private static final int MAX = 1000;
+
+    public static void main(String[] args) {
+        //获取当前时间毫秒值
+        System.out.println(System.currentTimeMillis());
+        //验证for循环打印数字1-9999所需要使用的时间(毫秒)
+        long start = System.currentTimeMillis();
+        for (int i = 0; i < MAX; i++) {
+            System.out.println(i);
+        }
+        long end = System.currentTimeMillis();
+        System.out.println("共耗时毫秒:" + (end - start));
+    }
+}
