_135_Java_Date與Calendar
阿新 • • 發佈:2018-12-12
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import java.text.ParseException; import java.text.SimpleDateFormat; import java.util.Calendar; import java.util.Date; import org.junit.Test; /* * 與時間相關的類 * 1、System類下的currentTimeMillis() * 2、Date類:Java.util.Date及其子類java.sql.Date * 3、SimpleDateFormat類 * 4、Calendar類 * */ public class _001_TestDateCalendar { //java.util.Date不易於國際化 @Test public void testDate() { Date date = new Date(); System.out.println(date.toString()); System.out.println(date.getTime()); Date date1 = new Date(8686225049L); System.out.println(date1); java.sql.Date date2 = new java.sql.Date(435874243); System.out.println(date2.toString()); } /* *java.text.SimpleDateFormat易於國際化 *格式化:日期-->文字(使用SimpleDateFormat的format()方法) *可以在JavaAPI中檢視pattern * 解析:文字-->日期 * * * */ @Test public void testSimpleDateFormat() { /*格式化1*/ SimpleDateFormat simpleDateFormat = new SimpleDateFormat(); String format = simpleDateFormat.format(new Date()); System.out.println(format); /*格式化2*/ SimpleDateFormat sDFA = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); String format2 = sDFA.format(new Date()); System.out.println(format2); /*3.解析,即字串轉化為日期(需要注意初始化的格式)*/ try { Date parse = sDFA.parse("2018-09-29 20:30:20"); System.out.println(parse); } catch (ParseException e) { // TODO Auto-generated catch block e.printStackTrace(); } } /* * 三天打魚兩天晒網 1990-01-01 XXXX-XX-XX 打魚?晒網 * * * 返回date1與date2之間的天數 * */ public int getDays(String date1,String date2) throws ParseException { SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd"); Date parse = sdf.parse(date1); Date parse2 = sdf.parse(date2); long time=parse2.getTime()-parse.getTime(); return (int)time/100/3600/24+1; } @Test public void test() throws ParseException { String str="1990-01-01"; String str1="2018-09-30"; int days = getDays(str, str1); if(days%5==0||days%5==4) { System.out.println("晒網"); }else { System.out.println("打魚"); } } /*Calendar類*/ public void testCalendar() { Calendar c = Calendar.getInstance(); int i = c.get(Calendar.DAY_OF_MONTH); System.out.println(i); c.add(Calendar.DAY_OF_MONTH, 2); i = c.get(Calendar.DAY_OF_MONTH); System.out.println(i); c.set(Calendar.DAY_OF_MONTH,23); i = c.get(Calendar.DAY_OF_MONTH); System.out.println(i); Date time = c.getTime(); System.out.println(time); } }