fixes #114

Author: GavinChenYan

src/main/java/com/networknt/schema/JsonMetaSchema.java

@@ -46,7 +46,7 @@ private static class DraftV4 {
         public static final List<Format> BUILTIN_FORMATS = new ArrayList<Format>();
         static {
             BUILTIN_FORMATS.add(pattern("date-time", 
-                    "^\\d{4}-(?:0[0-9]{1}|1[0-2]{1})-(0?[1-9]|[12][0-9]|3[01])[tT ]\\d{2}:\\d{2}:\\d{2}(\\.\\d+)?([zZ]|[+-]\\d{2}:\\d{2})$"));
+                    "^\\d{4}-(?:0[0-9]{1}|1[0-2]{1})-(0?[1-9]|[12][0-9]|3[01])[tT ]\\d{2}:\\d{2}:\\d{2}(\\.\\d+)?([zZ]?|[+-]\\d{2}:\\d{2})$"));
             BUILTIN_FORMATS.add(pattern("date", "^\\d{4}-(?:0[0-9]{1}|1[0-2]{1})-(0?[1-9]|[12][0-9]|3[01])$"));
             BUILTIN_FORMATS.add(pattern("time", "^\\d{2}:\\d{2}:\\d{2}$"));
             BUILTIN_FORMATS.add(pattern("email", "^\\S+@\\S+$"));

src/test/resources/tests/optional/format.json

@@ -24,10 +24,30 @@
                 "valid": false
             },
             {
-                "description": "an invalid date-time string",
+                "description": "an valid date-time string",
                 "data": "1963-12-31T08:30:06.283185Z",
                 "valid": true
             },
+            {
+                "description": "an valid date-time string",
+                "data": "1963-12-30T08:30:06.283Z",
+                "valid": true
+            },
+            {
+                "description": "an valid date-time string",
+                "data": "1963-12-30T08:30:06.283",
+                "valid": true
+            },
+            {
+                "description": "an valid date-time string",
+                "data": "1963-12-30T08:30:06",
+                "valid": true
+            },
+            {
+                "description": "an valid date-time string",
+                "data": "1963-12-30T08:30:06Z",
+                "valid": true
+            },
             {
                 "description": "only RFC3339 not all of ISO 8601 are valid",
                 "data": "2013-350T01:01:01",