/**      * 获取指定月的前一月（年）或后一月（年）      * @param dateStr      * @param addYear      * @param addMonth      * @param addDate      * @return 输入的时期格式为yyyy-MM，输出的日期格式为yyyy-MM      * @throws Exception      */      public static String getLastMonth(String dateStr,int addYear, int addMonth, int addDate) throws Exception {            try {            java.text.SimpleDateFormat sdf = new java.text.SimpleDateFormat("yyyy-MM");            java.util.Date sourceDate = sdf.parse(dateStr);            Calendar cal = Calendar.getInstance();            cal.setTime(sourceDate);            cal.add(Calendar.YEAR,addYear);            cal.add(Calendar.MONTH, addMonth);            cal.add(Calendar.DATE, addDate);            java.text.SimpleDateFormat returnSdf = new java.text.SimpleDateFormat("yyyy-MM");            String dateTmp = returnSdf.format(cal.getTime());            java.util.Date returnDate = returnSdf.parse(dateTmp);            return dateTmp;            } catch (Exception e) {            e.printStackTrace();            throw new Exception(e.getMessage());            }            }    /**      * 测试      * @param args      */      public static void main(String[] args) {            try{               System.out.println(getLastMonth("2011-06",0,-1,0));//2011-05               System.out.println(getLastMonth("2011-06",0,-6,0));//2010-12               System.out.println(getLastMonth("2011-06",-1,0,0));//2010-06            }catch (Exception e) {                        }        }