Java获取前7天后7天的日期

import java.util.*;
public class Test{
    public static void main(String[] args){
        Calendar calAfter=Calendar.getInstance(); 
        System.out.println("-------After 7 Days----------");
        for(int i =0;i<7;i++){
            System.out.println(calAfter.get(Calendar.DATE));
            calAfter.set(Calendar.DATE,calAfter.get(Calendar.DATE)+1); 
        }
        
        Calendar calBefore=Calendar.getInstance(); 
        System.out.println("-------Bofore 7 Days----------");
        for(int i =0;i<7;i++){
            System.out.println(calBefore.get(Calendar.DATE));
            calBefore.set(Calendar.DATE,calBefore.get(Calendar.DATE)-1); 
        }
    }
}