输入指定年月，打印该月日历运行效果如下：

public class Practise {
	/**
	 * 打印某年某月的日历 author:wangpeng time：2018年8月9日下午4:15:05
	 */
	@Test
	public void test2() {
		Calendar c=input();
		if(c==null) {
			return;
		}
		System.out.println("日\t一\t二\t三\t四\t五\t六");
		int start=c.get(Calendar.DAY_OF_WEEK);
		//System.out.println(start);
		for(int i=0;i<start-1;i++) {
			System.out.print(" \t");
		}
		for(int i=start;i<(c.getActualMaximum(Calendar.DAY_OF_MONTH))+start;i++) {
			System.out.print((i-start+1)+"\t");
			if(i%7==0)
				System.out.println();
		}
	}
	
	public Calendar input() {
		Scanner in = new Scanner(System.in);
		int year = 0;
		int mon = 0;
		Calendar c = Calendar.getInstance();
		while(true) {
			System.out.println("输入年份：");
			String strYear = in.next();
			System.out.println("输入月份：");
			String strMon = in.next();
			
			if (strYear.matches("\\d+") && strMon.matches("\\d+")) {
				year = Integer.parseInt(strYear);
				mon = Integer.parseInt(strMon);
				
				c.set(Calendar.YEAR, year);
				c.set(Calendar.MONTH, mon-1);
				c.set(Calendar.DATE, 1);
				break;
			} else {
				System.out.println("输入有误,请重新输入");
			}
			
		}
		System.out.println(year + "年" + mon + "月" + "日历如下：");
		return c;
	}
}