java的Calendar类

public class TestCalendar { 
2. 
3.    @Test 
4.    public void test(){ 
5.        try { 
6.            Calendar calendar = new GregorianCalendar();//子类实例化 
7.            //获取年、月、日、时、分、秒、毫秒 
8.            System.out.println("年： "+calendar.get(Calendar.YEAR)); 
9.            System.out.println("月 "+(calendar.get(Calendar.MONTH)+1)); 
10.            System.out.println("日： "+calendar.get(Calendar.DAY_OF_MONTH)); 
11.            System.out.println("时： "+calendar.get(Calendar.HOUR_OF_DAY)); 
12.            System.out.println("分： "+calendar.get(Calendar.MINUTE)); 
13.            System.out.println("秒： "+calendar.get(Calendar.SECOND)); 
14.            System.out.println("毫秒 "+calendar.get(Calendar.MILLISECOND)); 
15.             
16.            // 当前月第一天、最后一天 
17.            int currYear = calendar.get(Calendar.YEAR); 
18.            int currMonth = calendar.get(Calendar.MONTH) + 1; 
19.            System.out.print(currYear + "-" + currMonth); 
20.            SimpleDateFormat datef = new SimpleDateFormat("yyyy-MM-dd"); 
21.            calendar.set(Calendar.DAY_OF_MONTH, 1); 
22.            Date beginTime = calendar.getTime(); 
23.            String sTime = datef.format(beginTime) + " 00:00:00"; 
24.            calendar.set(Calendar.DATE, 1); 
25.            calendar.roll(Calendar.DATE, -1); 
26.            Date endTime = calendar.getTime(); 
27.            String eTime = datef.format(endTime) + " 23:59:59"; 
28.            System.out.println("第一天"+sTime+"最后一天"+eTime); 
29.             
30.            Calendar cal = Calendar.getInstance();  
31.            //指定年月的的第一天、最后一天 
32.            int year = 2015; 
33.            int moth = 3; 
34.            cal.set(Calendar.YEAR,year); 
35.            cal.set(Calendar.MONTH, moth-1); 
36.            //当前月的最后一天    
37.            cal.set( Calendar.DATE, 1 ); 
38.            cal.roll(Calendar.DATE, - 1 ); 
39.            Date endTime2=cal.getTime(); 
40.            String endTimeStr=datef.format(endTime2)+" 23:59:59"; 
41.            //当前月的第一天           
42.            cal.set(GregorianCalendar.DAY_OF_MONTH, 1);  
43.            Date beginTime2=cal.getTime(); 
44.            String beginTimeStr=datef.format(beginTime2)+" 00:00:00"; 
45.             
46.            System.out.println("指定年月的的第一天"+endTimeStr+"最后一天"+beginTimeStr); 
47.             
48.            //当前时间的前一天 
49.            SimpleDateFormat sdf2 = new SimpleDateFormat("yyyy-MM-dd:HH");   
50.            String tmStr = "2015-5-18:00"; 
51.            Date d = sdf2.parse(tmStr);   
52.            System.out.println(d); 
53.            Calendar now = Calendar.getInstance();   
54.            now.setTime(d);   
55.            now.set(Calendar.HOUR, now.get(Calendar.HOUR) -1);   
56.            System.out.println(sdf2.format(now.getTime())); 
57.             
58.            //最近N天 
59.            SimpleDateFormat df2 = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss"); 
60.            cal.add(Calendar.DATE,-7); 
61.            System.out.println("最近7天"+df2.format(cal.getTime())); 
62.            Calendar ca2 =Calendar.getInstance(); 
63.            //最近N个月 
64.            ca2.add(Calendar.MONTH,-1);//最近一个月 
65.            System.out.println("最近一个月"+df2.format(ca2.getTime())); 
66.            Calendar ca3 =Calendar.getInstance(); 
67.            //最近N个年 
68.            ca3.add(Calendar.YEAR,-1);//最近一年 
69.            System.out.println("最近一年"+df2.format(ca3.getTime())); 
70.        } catch (Exception e) { 
71.            e.printStackTrace(); 
72.        } 
73.    } 
74.}