获取指定 月份的前n月 返回yyyyMM

epmet-commons/epmet-commons-tools/src/main/java/com/epmet/commons/tools/utils/DateUtils.java

@@ -446,6 +446,22 @@ public class DateUtils {
         return DateUtils.format(date,DateUtils.DATE_PATTERN_YYYYMM);
     }
 
+    /**
+     * @Description  获取指定 月份的前n月 返回yyyyMM
+     * @Param beforeMonth
+     * @Param monthId
+     * @author zxc
+     * @date 2021/7/9 2:44 下午
+     */
+    public static  String getBeforeNMonthByMonth(int beforeMonth, String monthId){
+        StringBuilder builder = new StringBuilder(monthId);
+        builder.insert(NumConstant.FOUR,"-");
+        builder.insert(builder.length(),"-01");
+        LocalDate parse = LocalDate.parse(builder.toString());
+        LocalDate localDate = parse.minusMonths(beforeMonth);
+        return localDate.toString().replace("-","").substring(NumConstant.ZERO,NumConstant.SIX);
+    }
+
     /**
      * @return java.util.List<java.lang.String> 返回yyyyMMdd
      * @param startTime yyyyMMdd