获取今天，昨天，上个月的日期 的方法：

 



    Calendar cal = Calendar.getInstance();
    //获取今天的日期
    cal.setTime(new Date());
    int year = cal.get(Calendar.YEAR); 
    int month = cal.get(Calendar.MONTH)+1; 
    int day = cal.get(Calendar.DAY_OF_MONTH); 
    logger.debug(year + " 年 " + month + " 月 " + day +  " 日");
    Date date = cal.getTime();
    SimpleDateFormat format1= new SimpleDateFormat("yyyy-MM");
    String dateStringYYYYMM = format1.format(date);
    logger.debug(dateStringYYYYMM);
    SimpleDateFormat format11= new SimpleDateFormat("yyyy-MM-dd");
    String dateStringYYYYMMDD = format11.format(date);
    logger.debug(dateStringYYYYMMDD);
    
    //获取昨天的日期
    cal.setTime(new Date());
    //cal2.set(2018, 2, 1);
    cal.add(Calendar.DATE, -1);
    int year2 = cal.get(Calendar.YEAR); 
    int month2 = cal.get(Calendar.MONTH)+1; 
    int day2 = cal.get(Calendar.DAY_OF_MONTH); 
    logger.debug(year2 + " 年 " + month2 + " 月 " + day2 +  " 日");
    Date date2 = cal.getTime();
    SimpleDateFormat format2= new SimpleDateFormat("yyyy-MM-dd");
    String dateStringYYYYMMDD2 = format2.format(date2);
    logger.debug(dateStringYYYYMMDD2);
    
    //获取上个月的日期（上个月的今天）
    cal.setTime(new Date());
    cal.add(Calendar.MONTH, -1);
    int year3 = cal.get(Calendar.YEAR); 
    int month3 = cal.get(Calendar.MONTH)+1; 
    int day3 = cal.get(Calendar.DAY_OF_MONTH); 
    logger.debug(year3 + " 年 " + month3 + " 月 " + day3 +  " 日");
    Date date3 = cal.getTime();
    SimpleDateFormat format3= new SimpleDateFormat("yyyy-MM-dd");
    String dateStringYYYYMMDD3 = format3.format(date3);
    logger.debug(dateStringYYYYMMDD3);