[Bug] [seatunnel-formats] Allow the entry in the map to be null and a…

…llow the key in the entry to be null (#5277)

* 🐛 "Add null check in text deserialization

This commit adds a null check while splitting the kv in the TextDeserializationSchema. Not having this check could potentially lead to a crash if 'kvs' has less than two elements. Now, the function will return null in this case, significantly improving reliability."

* 🐛 Refactor text deserialization, allow null value assignments

Modified the TextDeserializationSchema to allow key-value pairs with null values. This adjustment helps to handle data records with missing values more accurately. The code was also reformatted for improved readability.

* 🎨 Refactor Builder constructor in TextDeserializationSchema

Tidied up the Builder constructor in TextDeserializationSchema by removing unnecessary empty lines. This change improves code readability and consistency with the rest of the class?

* ✅ Add  test case where the value is empty and the key is empty in the map

---------

Co-authored-by: yangpeng <nickyooungp@gmail.com>

seatunnel-formats/seatunnel-format-text/src/main/java/org/apache/seatunnel/format/text/TextDeserializationSchema.java

@@ -187,9 +187,13 @@ private Object convert(String field, SeaTunnelDataType<?> fieldType, int level)
                 String[] kvs = field.split(separators[level + 1]);
                 for (String kv : kvs) {
                     String[] splits = kv.split(separators[level + 2]);
-                    objectMap.put(
-                            convert(splits[0], keyType, level + 1),
-                            convert(splits[1], valueType, level + 1));
+                    if (splits.length < 2) {
+                        objectMap.put(convert(splits[0], keyType, level + 1), null);
+                    } else {
+                        objectMap.put(
+                                convert(splits[0], keyType, level + 1),
+                                convert(splits[1], valueType, level + 1));
+                    }
                 }
                 return objectMap;
             case STRING:

seatunnel-formats/seatunnel-format-text/src/test/java/org/apache/seatunnel/format/text/TextFormatSchemaTest.java

@@ -45,7 +45,14 @@ public class TextFormatSchemaTest {
                     + '\002'
                     + "Kris"
                     + '\003'
-                    + "21\001"
+                    + "21"
+                    + '\002'
+                    + "nullValueKey"
+                    + '\003'
+                    + '\002'
+                    + '\003'
+                    + "1231"
+                    + "\001"
                     + "tyrantlucifer\001"
                     + "true\001"
                     + "1\001"