自学Jav测试代码三 Math类 & Date & GregorianCalendar类
2017-08-23 20:30:08
writer: pprp
package test; import java.util.Date; import java.util.*; public class class_test { public static void main(String[] args) { // TODO Auto-generated method stub System.out.println(Math.pow(2, 3)); double a = 100 * Math.random(); double x = 4.51; System.out.println(a); System.out.println(Math.sqrt(a)); System.out.println(Math.max(a, 10)); //Math中的方法和字段属性都是静态的所以可以直接使用它们 //四舍五入 System.out.println(Math.round(x)); //向下取整 System.out.println(Math.floor(x)); //测试时间和日期的类date //输出当前时间 System.out.println(new Date()); //测试日历的类GregorianCalendar GregorianCalendar gc = new GregorianCalendar(); int y = gc.get(Calendar.MONTH); System.out.println(y); gc.set(Calendar.YEAR, 2019); System.out.println(gc.get(Calendar.YEAR)); gc.set(2017,8,17); System.out.println(gc.get(Calendar.YEAR)); System.out.println(gc.get(Calendar.MONTH)); System.out.println(gc.get(Calendar.DATE)); //获得系统当前时间 String now = gc.get(Calendar.YEAR) + "年" + gc.get(Calendar.MONTH) + "月" + gc.get(Calendar.DATE) + "日" + gc.get(Calendar.HOUR) + "小时" + gc.get(Calendar.MINUTE) + "分" + gc.get(Calendar.SECOND) + "秒" ; System.out.println(now); //给你一个人的生日,分析每年的生日是星期几? final char[] kor_week = {'日','一','二','三','四','五','六'}; for(int i = 2010 ; i <= 2020 ; i++) { gc.set(i,Calendar.JULY,20); //设置日期 char week = kor_week[gc.get(Calendar.DAY_OF_WEEK) - 1]; System.out.println(i + "年的生日是星期" + week); } } }
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