Java获取当前日期的前一个月，前一天的时间

Calendar calendar = Calendar.getInstance();
calendar.add(Calendar.DATE, -1);    //得到前一天
calendar.add(Calendar.MONTH, -1);    //得到前一个月
int year = calendar.get(Calendar.YEAR);
int month = calendar.get(Calendar.MONTH)+1;
注意月份加一


/** 
    * 判断当前日期是星期几<br> 
    * <br> 
    * @param pTime 修要判断的时间<br> 
    * @return dayForWeek 判断结果<br> 
    * @Exception 发生异常<br> 
    */ 
public static int dayForWeek(String pTime) throws Exception {  
format = new SimpleDateFormat("yyyy-MM-dd");  
Calendar c = Calendar.getInstance();  
c.setTime(format.parse(pTime));  
int dayForWeek = 0;  
if(c.get(Calendar.DAY_OF_WEEK) == 1){  
  dayForWeek = 7;  
}else{  
  dayForWeek = c.get(Calendar.DAY_OF_WEEK) - 1;  
}  
return dayForWeek;  
}