获取当前月份的上个月的第一天和最后一天

public static void main(String[] args) {
    //获取当前月份
    SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd");
    String firstday, lastday;
    Calendar c = Calendar.getInstance();
    c.setTime(new Date());
    //当前月份减1
    c.add(Calendar.MONTH, -1);

    // 获取上个月的第一天
    c.set(Calendar.DAY_OF_MONTH, 1);
    firstday = df.format(c.getTime());
    // 获取上个月的最后一天
    c = Calendar.getInstance();
    c.set(Calendar.DAY_OF_MONTH, 0);
    lastday = df.format(c.getTime());

    System.out.println("上个月第一天："+firstday+";上个月最后一天："+lastday);
}