DateTime计算未来时间

写着玩的一小段代码：

import org.apache.commons.collections.MapUtils;
import org.apache.commons.lang3.StringUtils;
import org.joda.time.DateTime;
import org.joda.time.format.DateTimeFormat;
import org.joda.time.format.DateTimeFormatter;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.common.base.Preconditions;
import com.google.common.collect.Maps;

import java.util.Map;

public class App {


    public static void main(String[] args) {


        Map<String,Integer> map = Maps.newLinkedHashMap();
        map.put("入职一个月",30);
        map.put("入职半年",180);
        map.put("入职一年",365);
        
        calcute("2019-01-09", map);
        // output 
        // 入职一个月:  2019-02-08(星期五)
        // 入职半年:   2019-07-08(星期一)
        // 入职一年:   2020-01-09(星期四)
    }
    
    public static void calcute(String baseDate,Map<String,Integer> durationMap) {
        Preconditions.checkArgument(StringUtils.isNotBlank(baseDate));
        Preconditions.checkArgument(MapUtils.isNotEmpty(durationMap));
        DateTimeFormatter formatter = DateTimeFormat.forPattern("yyyy-MM-dd");
        DateTime dateTime = DateTime.parse(baseDate, formatter);
        durationMap.entrySet().stream().forEach(entry -> {
            int days = entry.getValue();      
            DateTime tmp =    dateTime.dayOfYear().addToCopy(days);
            String week = tmp.dayOfWeek().getAsShortText();          
            System.out.println(String.format("%s:\t%s(%s)", entry.getKey(),
                    tmp.toString(formatter),week));
        });
    }
    
}