Java的学习03

 1 import java.text.DateFormat;
 2 import java.text.ParseException;
 3 import java.text.SimpleDateFormat;
 4 import java.util.Date;
 5 
 6 /**
 7  * 测试时间对象和字符串之间的相互转换
 8  * DateFormat抽象类和SimpleDateFormat实现类
 9  * @author 小白
10  *
11  */
12 
13 public class TestDateFormat {
14     public static void main(String[] args) throws ParseException {
15         
16         //把时间对象按照“格式字符串指定的格式”转成相应的字符串
17         DateFormat df = new SimpleDateFormat("yyyy年MM月dd日  hh:mm:ss");
18         String str = df.format(new Date(40000000));
19         System.out.println(str);
20         
21         //把字符串按照“格式字符串指定的格式”转成相应的时间对象
22         DateFormat df2 = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
23         Date date = df2.parse("1983-05-10 10:44:34");
24         System.out.println(date);
25         
26         //测试其他的格式字符。比如：利用D，获得本时间对象是所处年份的第几天
27         DateFormat df3 = new SimpleDateFormat("D");
28         String str3 = df3.format(new Date());
29         System.out.println(str3);
30         
31         
32     }
33 
34 }

 1 import java.util.Calendar;
 2 import java.util.Date;
 3 import java.util.GregorianCalendar;
 4 
 5 /**
 6  * 测试日期类的使用
 7  * @author 小白
 8  *
 9  */    
10 
11 public class Testcalender {
12     public static void main(String[] args) {
13         
14         Calendar calendar = new GregorianCalendar(2999, 10, 9, 22, 10, 50);
15         int year = calendar.get(Calendar.YEAR);
16         int month = calendar.get(Calendar.MONTH);
17         int day = calendar.get(Calendar.DATE);
18         int weekday = calendar.get(Calendar.DAY_OF_WEEK);//星期几。1-7
19         
20         System.out.println(year);
21         System.out.println(day);
22         System.out.println(month);//0-11表示对应的月份，0是1月，1是2月，依次类推
23         System.out.println(weekday);
24         
25         
26         
27         //设置日期的相关元素
28         Calendar c2 = new GregorianCalendar();
29         c2.set(Calendar.YEAR, 8012);
30         
31         System.out.println(c2);
32         
33         //日期的计算
34         Calendar c3 = new GregorianCalendar();
35         c3.add(Calendar.DATE, 100);
36         System.out.println(c3);
37         
38         //日期对象和时间对象的转化
39         Date d4 = c3.getTime();
40         Calendar c4 = new GregorianCalendar();
41         c4.setTime(new Date());
42         
43         printCalendar(c4);
44     }
45     
46     public static void printCalendar(Calendar c){
47         //打印：1918年10月10日  11：23：45 周三
48         
49         int year = c.get(Calendar.YEAR);
50         int month = c.get(Calendar.MONTH)+1;
51         int date = c.get(Calendar.DAY_OF_MONTH);
52         int dayweek = c.get(Calendar.DAY_OF_WEEK);
53         
54         String dayweek2 = dayweek==0?"日":dayweek+"";
55         int hour = c.get(Calendar.HOUR);
56         int minte = c.get(Calendar.MINUTE);
57         int second = c.get(Calendar.SECOND);
58         
59         System.out.println(year+"年"+month+"月"+date+"日"+hour+"时"+minte+"分"+second+"秒"+
60                 "周"+dayweek2);
61         
62     }
63 }

 1 import java.text.DateFormat;
 2 import java.text.ParseException;
 3 import java.text.SimpleDateFormat;
 4 import java.util.Calendar;
 5 import java.util.Date;
 6 import java.util.GregorianCalendar;
 7 import java.util.Scanner;
 8 
 9 /**
10  * 可视化日历程序
11  * @author 小白
12  *
13  */
14 public class TestCalendar02 {
15     public static void main(String[] args) throws ParseException {
16         System.out.println("请输入日期（如：2010-10-20）：");
17         Scanner scanner = new Scanner(System.in);
18         String str = scanner.nextLine();
19         
20         DateFormat df = new SimpleDateFormat("yyyy-MM-dd");
21         Date date = df.parse(str);//时间对象
22         Calendar c = new GregorianCalendar();
23         c.setTime(date);
24         int day = c.get(Calendar.DAY_OF_MONTH);
25         int days = c.getActualMaximum(Calendar.DAY_OF_MONTH);
26         
27         System.out.println("日\t一\t二\t三\t四\t五\t六\t");
28         
29         c.set(Calendar.DAY_OF_MONTH, 1);        
30         
31         for(int i=0;i<c.get(Calendar.DAY_OF_WEEK)-1;i++){
32             System.out.print("\t");
33         }         
34         
35         for(int i=0;i<days;i++){
36             
37             if(c.get(Calendar.DAY_OF_MONTH)==day){
38                 System.out.print(c.get(Calendar.DAY_OF_MONTH)+"*\t");
39             }else{
40                 System.out.print(c.get(Calendar.DAY_OF_MONTH)+"\t");
41             }
42              
43             if(c.get(Calendar.DAY_OF_WEEK)==Calendar.SATURDAY){
44                 System.out.println();//换行
45             }
46              
47             c.add(Calendar.DAY_OF_MONTH, 1);
48         }
49         
50          
51     }
52 }