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Colinasda · web-flow · commit 89af482d0df2 · 2021-03-06T00:14:33.000+08:00
diff --git a/JavaCode/Date/CalendarTest.java b/JavaCode/Date/CalendarTest.java
@@ -0,0 +1,42 @@
+package Date;
+
+import org.junit.Test;
+
+import java.util.Calendar;
+import java.util.Date;
+
+public class CalendarTest {
+    @Test
+    public void testCalendar(){
+        //实例化
+        Calendar calendar = Calendar.getInstance();
+        System.out.println(calendar.getClass());
+
+        //常用方法
+        //get()
+        int days = calendar.get(Calendar.DAY_OF_MONTH);
+        System.out.println(days);
+
+        //set()
+        calendar.set(Calendar.DAY_OF_MONTH,24);
+        days = calendar.get(Calendar.DAY_OF_MONTH);
+        System.out.println(days);
+
+        //add()
+        calendar.add(Calendar.DAY_OF_MONTH,-4);
+        days = calendar.get(Calendar.DAY_OF_MONTH);
+        System.out.println(days);
+
+        //getTime():日历类转换为Date
+        Date date = calendar.getTime();
+        System.out.println(date);
+
+        //setTime（）：Date转换为日历类
+        Date date1 = new Date();
+        calendar.setTime(date1);
+        days = calendar.get(Calendar.DAY_OF_MONTH);
+        System.out.println(days);
+
+    }
+
+}
diff --git a/JavaCode/Date/DateTimeTest.java b/JavaCode/Date/DateTimeTest.java
@@ -0,0 +1,29 @@
+package Date;
+
+import org.junit.Test;
+
+import java.util.Date;
+
+public class DateTimeTest {
+    @Test
+    public void test2(){
+        //构造器一：创建当前时间的Date对象
+        Date date1 = new Date();
+        System.out.println(date1.toString());//Tue Aug 25 09:51:25 CST 2020
+        System.out.println(date1.getTime());//1598320388310
+
+        //构造器二：创建指定毫秒数的Date对象
+        Date date2 = new Date(1598320388310L);
+        System.out.println(date2.toString());
+
+        java.sql.Date date3 = new java.sql.Date(1598320388310L);
+        System.out.println(date3);//2020-08-25
+    }
+
+
+    @Test
+    public void test1(){
+        long time = System.currentTimeMillis();
+        System.out.println(time);
+    }
+}
diff --git a/JavaCode/Date/JDK8DateTimeTest.java b/JavaCode/Date/JDK8DateTimeTest.java
@@ -0,0 +1,20 @@
+package Date;
+
+import org.junit.Test;
+
+import java.time.LocalDate;
+import java.time.LocalDateTime;
+import java.time.LocalTime;
+
+public class JDK8DateTimeTest {
+    @Test
+    public void test(){
+        LocalDate localDate = LocalDate.now();
+        LocalTime localTime = LocalTime.now();
+        LocalDateTime localDateTime = LocalDateTime.now();
+
+        System.out.println(localDate);
+        System.out.println(localTime);
+        System.out.println(localDateTime);
+    }
+}
diff --git a/JavaCode/Date/SimpleDateFormatTest.java b/JavaCode/Date/SimpleDateFormatTest.java
@@ -0,0 +1,31 @@
+package Date;
+
+import org.junit.Test;
+
+import java.text.ParseException;
+import java.text.SimpleDateFormat;
+import java.util.Date;
+
+public class SimpleDateFormatTest {
+    @Test
+    public void test() throws ParseException {
+        SimpleDateFormat simpleDateFormat = new SimpleDateFormat();
+
+        Date date = new Date();
+        System.out.println(date);
+
+        //格式化：Date转换为String
+        String str = simpleDateFormat.format(date);
+        System.out.println(str);
+
+        //解析，格式化的逆过程
+        Date date1 = simpleDateFormat.parse("20-8-27 上午10:06");
+        System.out.println(date1);
+
+        //带参数的构造器
+        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
+        String format1 = sdf.format(date);
+        System.out.println(format1);
+    }
+
+}
