1.String、Date、Calendar之间的转换

　　要用到格式化类SimpleDateFormat

 1 package com.rong.se;
 2
 3 import java.text.ParseException;
 4 import java.text.SimpleDateFormat;
 5 import java.util.Calendar;
 6 import java.util.Date;
 7
 8 public class StringDate {
 9
10     public static void main(String[] args) {
11         // 格式化对象
12         SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
13         // SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
14         // /////////////////////////////////////////////////////
15         // SimpleDateFormat sdf=new SimpleDateFormat();
16         // sdf.applyPattern("yyyy-MM-dd hh:mm:ss");
17
18         try {
19             // String类型转换为Date类型
20             String string = "2017-11-11 20:20:20";
21             Date date = sdf.parse(string);
22             System.out.println(date);
23
24         } catch (ParseException e) {
25             e.printStackTrace();
26         }
27
28         // Date类型转换为String类型
29         Date date = new Date();
30         String format = sdf.format(date);
31         System.out.println(format);
32
33         // Calendar类型转换为Date类型
34         Calendar calendar = Calendar.getInstance();
35         Date cDate = calendar.getTime();
36         System.out.println(cDate);
37
38         // Date类型转换为Calendar类型
39         try {
40             String string = "1995-09-24 13:14:03";
41             Date parse = sdf.parse(string);
42             // ///////////////////////////////////
43             calendar.setTime(parse);
44             // 获取年份
45             System.out.println(calendar.get(Calendar.YEAR));
46
47         } catch (ParseException e) {
48             e.printStackTrace();
49         }
50         // String类型转换为Calendar类型
51         try {
52             String str = "2002-01-01 18:30:00";
53             Date parse = sdf.parse(str);
54             Calendar instance = Calendar.getInstance();
55             instance.setTime(parse);
56             System.out.println(instance.get(Calendar.YEAR));
57         } catch (ParseException e) {
58             e.printStackTrace();
59         }
60         // Calendar类型转换为String类型
61         Calendar instance = Calendar.getInstance();
62         Date time = instance.getTime();
63         String string = sdf.format(time);
64         System.out.println(string);
65
66     }
67
68 }