《Java核心技术卷Ⅰ》读书笔记——4.2.2 预定义类LocalDate类

不要使用构造器来构造LoaclDate类的对象。应当使用静态工厂方法（factory method）代表你调用构造器。

LocalDate.now()

LocalDate.of(1999, 12, 31

调用更改器方法会改变对象的状态；相反，访问器方法只访问对象而不修改对象。

下面应用LocalDate类编写程序显示当前月的日历，格式为：

package coding;

import java.time.LocalDate;
import java.time.DayOfWeek;

public class CalendarTest {
	public static void main(String[] args) {
		LocalDate date = LocalDate.now();
		int today = date.getDayOfMonth();
		int month = date.getMonthValue();
		date = date.minusDays(today - 1);
		
		System.out.println("Mon Tue Wed Thu Fri Sat Sun");
		DayOfWeek weekday = date.getDayOfWeek();
		int value = weekday.getValue();
		for(int i = 1; i < value; i++) {
			System.out.print("    ");
		}
		
		while(date.getMonthValue() == month) {
			System.out.printf("%3d", date.getDayOfMonth());
			if(date.getDayOfMonth() == today)
				System.out.print("*");
			else
				System.out.print(" ");
			date = date.plusDays(1);
			if(date.getDayOfWeek().getValue() == 1) System.out.println();
		}
	}
}

程序输出结果：