java基础 API Calendar类

 Calendar日历类 ：

package daysreplace;
 
import com.sun.jdi.IntegerValue;
 
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Arrays;
import java.util.Calendar;
import java.util.Date;
 
public class Test {
    public static void main(String[] args) throws ParseException {
        Calendar c = Calendar.getInstance();
 
        int year = c.get(Calendar.YEAR);
        int month = c.get(Calendar.MONTH);
        int day = c.get(Calendar.DATE);
        
        //获取月份 从0开始 需要+1
        System.out.println(year + "年" + (month + 1) + "月" + day + "日");
    }
}

 

package daysreplace;
 
import com.sun.jdi.IntegerValue;
 
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Arrays;
import java.util.Calendar;
import java.util.Date;
 
public class Test {
    public static void main(String[] args) throws ParseException {
        Calendar c = Calendar.getInstance();
 
        //加10年
        c.add(Calendar.YEAR,10);
 
        int year = c.get(Calendar.YEAR);
        int month = c.get(Calendar.MONTH);
        int day = c.get(Calendar.DATE);
 
        //获取月份 从0开始 需要+1
        System.out.println(year + "年" + (month + 1) + "月" + day + "日");
     
    }
}

 小案例：二月有多少天？

package daysreplace;
 
import com.sun.jdi.IntegerValue;
 
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Arrays;
import java.util.Calendar;
import java.util.Date;
import java.util.Scanner;
 
public class Test {
    public static void main(String[] args) throws ParseException {
        System.out.println("请输入年份");
        Scanner sc = new Scanner(System.in);
        int year = sc.nextInt();
 
        Calendar c = Calendar.getInstance();
        c.set(year,2,1);
        c.add(Calendar.DATE,-1);
        
        System.out.println(year+"年的二月有"+c.get(Calendar.DATE)+"天");
 
    }
}