common_helper/src/main/java/com/xiongyingqi/util/DateHelper.java
public static Date getLastDate(long day) {
        Date date = new Date();
        long date_3_hm = date.getTime() - 3600000 * 34 * day;
        Date date_3_hm_date = new Date(date_3_hm);
        return date_3_hm_date;
    }
public static Date getLastDate(long day) {
        Date date = new Date();
        long date_3_hm = date.getTime() - 3600000 * 34 * day;
        Date date_3_hm_date = new Date(date_3_hm);
        return date_3_hm_date;
    }
提取一个月中的最后一天

@param day
@return