java获取上月份日期

/**
     * 获取上个月的最后一天23点59分59秒的时间
     */
    private  String getBeforeLastMonthdate()throws Exception{
        SimpleDateFormat sf=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        Calendar calendar=Calendar.getInstance();
        int month=calendar.get(Calendar.MONTH);
        calendar.set(Calendar.MONTH, month-1);
        calendar.set(Calendar.DAY_OF_MONTH, calendar.getActualMaximum(Calendar.DAY_OF_MONTH));
        //将小时至23
        calendar.set(Calendar.HOUR_OF_DAY, 23);
        //将分钟至59
        calendar.set(Calendar.MINUTE, 59);
        //将秒至59
        calendar.set(Calendar.SECOND,59);
        String format = sf.format(calendar.getTime());
        return format;
    }

/**
     * 获取上一个月1号0点0分0秒的时间
     */
    private  String getBeforeFirstMonthdate()throws Exception{
        SimpleDateFormat format=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        Calendar calendar=Calendar.getInstance();
        calendar.add(Calendar.MONTH, -1);
        calendar.set(Calendar.DAY_OF_MONTH, 1);
        //将小时至23
        calendar.set(Calendar.HOUR_OF_DAY, 23);
        //将分钟至59
        calendar.set(Calendar.MINUTE, 59);
        //将秒至59
        calendar.set(Calendar.SECOND,59);
        String format1 = format.format(calendar.getTime());
        return format1;
    }

				Calendar c = Calendar.getInstance();
                //当前日期设置为指定日期
                c.setTime(new Date());
                //指定日期月份减去一
                c.add(Calendar.MONTH, -1);
                //指定日期月份减去一后的 最大天数
                c.set(Calendar.DATE, c.getActualMaximum(Calendar.DATE));
                //获取上给月最后一天的日期
                Date lastDateOfPrevMonth = c.getTime();