修改时间工具类格式化时间

mec-education/src/main/java/com/ym/mec/education/utils/DateUtil.java

@@ -23,8 +23,7 @@ public class DateUtil {
     private static ThreadLocal<DateFormat> threadLocal = new ThreadLocal<DateFormat>();
 
     public static DateFormat getDateFormat(String dateFormat) {
-        DateFormat df = threadLocal.get();
-        df = new SimpleDateFormat(dateFormat);
+        DateFormat df = new SimpleDateFormat(dateFormat);
         threadLocal.set(df);
         return df;
     }