Java获取一年有多少周、某周的第一天和最后一天

mahaijiang

Java获取一年有多少周、某周的第一天和最后一天.

原文地址:http://blog.csdn.net/dragonvsdragon/article/details/7034007

1. import java.text.SimpleDateFormat;
   
2. import java.util.Calendar;
   
3. import java.util.Date;
   
4. import java.util.GregorianCalendar;
   
5. 
   
6. 
   
7. public class Test {
   
8. 
   
9.     // 获取当前时间所在年的周数
   
10.     public static int getWeekOfYear(Date date) {
    
11.         Calendar c = new GregorianCalendar();
    
12.         c.setFirstDayOfWeek(Calendar.MONDAY);
    
13.         c.setMinimalDaysInFirstWeek(7);
    
14.         c.setTime(date);
    
15. 
    
16.         return c.get(Calendar.WEEK_OF_YEAR);
    
17.     }
    
18. 
    
19.     // 获取当前时间所在年的最大周数
    
20.     public static int getMaxWeekNumOfYear(int year) {
    
21.         Calendar c = new GregorianCalendar();
    
22.         c.set(year, Calendar.DECEMBER, 31, 23, 59, 59);
    
23. 
    
24.         return getWeekOfYear(c.getTime());
    
25.     }
    
26. 
    
27.     // 获取某年的第几周的开始日期
    
28.     public static Date getFirstDayOfWeek(int year, int week) {
    
29.         Calendar c = new GregorianCalendar();
    
30.         c.set(Calendar.YEAR, year);
    
31.         c.set(Calendar.MONTH, Calendar.JANUARY);
    
32.         c.set(Calendar.DATE, 1);
    
33. 
    
34.         Calendar cal = (GregorianCalendar) c.clone();
    
35.         cal.add(Calendar.DATE, week * 7);
    
36. 
    
37.         return getFirstDayOfWeek(cal.getTime());
    
38.     }
    
39. 
    
40.     // 获取某年的第几周的结束日期
    
41.     public static Date getLastDayOfWeek(int year, int week) {
    
42.         Calendar c = new GregorianCalendar();
    
43.         c.set(Calendar.YEAR, year);
    
44.         c.set(Calendar.MONTH, Calendar.JANUARY);
    
45.         c.set(Calendar.DATE, 1);
    
46. 
    
47.         Calendar cal = (GregorianCalendar) c.clone();
    
48.         cal.add(Calendar.DATE, week * 7);
    
49. 
    
50.         return getLastDayOfWeek(cal.getTime());
    
51.     }
    
52. 
    
53.     // 获取当前时间所在周的开始日期
    
54.     public static Date getFirstDayOfWeek(Date date) {
    
55.         Calendar c = new GregorianCalendar();
    
56.         c.setFirstDayOfWeek(Calendar.MONDAY);
    
57.         c.setTime(date);
    
58.         c.set(Calendar.DAY_OF_WEEK, c.getFirstDayOfWeek()); // Monday
    
59.         return c.getTime();
    
60.     }
    
61. 
    
62.     // 获取当前时间所在周的结束日期
    
63.     public static Date getLastDayOfWeek(Date date) {
    
64.         Calendar c = new GregorianCalendar();
    
65.         c.setFirstDayOfWeek(Calendar.MONDAY);
    
66.         c.setTime(date);
    
67.         c.set(Calendar.DAY_OF_WEEK, c.getFirstDayOfWeek() + 6); // Sunday
    
68.         return c.getTime();
    
69.     }
    
70. 
    
71.     public static void main(String[] args) {
    
72.         int year = 2015;
    
73.         int week = 27;
    
74. 
    
75.         SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    
76.         Date today = new Date();
    
77.         Calendar c = new GregorianCalendar();
    
78.         c.setTime(today);
    
79. 
    
80.         System.out.println("当前时间:current date = " + sdf.format(today));
    
81.         System.out.println("当前第几周:getWeekOfYear = " + getWeekOfYear(today));
    
82.         System.out.println("年度总周数:getMaxWeekNumOfYear = " + getMaxWeekNumOfYear(year));
    
83.         System.out.println("本周第一天:getFirstDayOfWeek = " + sdf.format(getFirstDayOfWeek(year, week)));
    
84.         System.out.println("本周最后一天:getLastDayOfWeek = " + sdf.format(getLastDayOfWeek(year, week)));
    
85.         System.out.println("本周第一天:getFirstDayOfWeek = " + sdf.format(getFirstDayOfWeek(today)));
    
86.         System.out.println("本周最后一天:getLastDayOfWeek = " + sdf.format(getLastDayOfWeek(today)));
    
87.     }
    
88. }
    
89. 
    
90. 
    
91.         
    
92.         //输出结果:
    
93. //        当前时间:current date = 2015-07-07 16:35:07
    
94. //        当前第几周:getWeekOfYear = 27
    
95. //        年度总周数:getMaxWeekNumOfYear = 52
    
96. //        getFirstDayOfWeek = 2015-07-06 16:35:07
    
97. //        getLastDayOfWeek = 2015-07-12 16:35:07
    
98. //        getFirstDayOfWeek = 2015-07-06 16:35:07
    
99. //        getLastDayOfWeek = 2015-07-12 16:35:07

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