java日期

 获取本月第一天和获取下一个月的第一天

    Date date = new Date();  
    SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd");  
    Calendar calendar = Calendar.getInstance();     
    calendar.setTime(date);
    String startcleardate=sdf.format(calendar.getTime());//获取本月第一天
    calendar.setTime(date);
    calendar.add(Calendar.MONTH,1); //将当前日期加一个月
    String endcleardate=sdf.format(calendar.getTime());//获取下一个月的第一天

Calendar calendar = Calendar.getInstance();     
 calendar.set(Calendar.DAY_OF_MONTH, calendar.getActualMinimum(Calendar.DAY_OF_MONTH));
 String monthfirstday=sdf.format(calendar.getTime());//获取本月第一天
 calendar.set(Calendar.DAY_OF_MONTH, calendar.getActualMaximum(Calendar.DAY_OF_MONTH));
 String monthlastday=sdf.format(calendar.getTime());//获取本月最后一天

 //取当前系统时间和下月的今天

SimpleDateFormat formatter = new SimpleDateFormat("yyyyMMdd");
  System.out.println(formatter.format(new Date()));// new Date()为获取当前系统时间
  Calendar calendar = Calendar.getInstance();
  calendar.add(Calendar.MONTH, 1);
  System.out.println(formatter.format(calendar.getTime()));//取下个月的今天日期