fix[orm]: map null value support

orm/src/main/java/com/zfoo/orm/codec/IntMapCodec.java

@@ -32,8 +32,14 @@ public class IntMapCodec<V> implements Codec<Map<Integer, V>> {
     public void encode(final BsonWriter writer, final Map<Integer, V> map, final EncoderContext encoderContext) {
         writer.writeStartDocument();
         for (var entry : map.entrySet()) {
-            writer.writeName(entry.getKey().toString());
-            valueCodec.encode(writer, entry.getValue(), encoderContext);
+            var key = entry.getKey();
+            var value = entry.getValue();
+            writer.writeName(key.toString());
+            if (value == null) {
+                writer.writeNull();
+            } else {
+                valueCodec.encode(writer, entry.getValue(), encoderContext);
+            }
         }
         writer.writeEndDocument();
     }

orm/src/main/java/com/zfoo/orm/codec/LongMapCodec.java

@@ -31,9 +31,15 @@ public class LongMapCodec<V> implements Codec<Map<Long, V>> {
     @Override
     public void encode(final BsonWriter writer, final Map<Long, V> map, final EncoderContext encoderContext) {
         writer.writeStartDocument();
-        for (final Map.Entry<Long, V> entry : map.entrySet()) {
-            writer.writeName(entry.getKey().toString());
-            valueCodec.encode(writer, entry.getValue(), encoderContext);
+        for (var entry : map.entrySet()) {
+            var key = entry.getKey();
+            var value = entry.getValue();
+            writer.writeName(key.toString());
+            if (value == null) {
+                writer.writeNull();
+            } else {
+                valueCodec.encode(writer, entry.getValue(), encoderContext);
+            }
         }
         writer.writeEndDocument();
     }
@@ -44,7 +50,12 @@ public class LongMapCodec<V> implements Codec<Map<Long, V>> {
         var map = new HashMap<Long, V>();
         while (!BsonType.END_OF_DOCUMENT.equals(reader.readBsonType())) {
             long key = Long.parseLong(reader.readName());
-            V value = BsonType.NULL.equals(reader.getCurrentBsonType()) ? null : valueCodec.decode(reader, context);
+            V value = null;
+            if (BsonType.NULL.equals(reader.getCurrentBsonType())) {
+                reader.readNull();
+            } else {
+                value = valueCodec.decode(reader, context);
+            }
             map.put(key, value);
         }
         reader.readEndDocument();

orm/src/test/java/com/zfoo/orm/accessor/MapTest.java

@@ -55,6 +55,7 @@ public class MapTest {
         bagMap.put("bag1", bagItem1);
         bagMap.put("bag2", bagItem2);
         bagMap.put("bag3", bagItem3);
+        bagMap.put("bag4", null);
 
         var map = new HashMap<String, Map<String, String>>();
         map.put("a", Map.of("b", "b"));
@@ -63,6 +64,7 @@ public class MapTest {
         var longStringHashMap = new HashMap<Long, String>();
         longStringHashMap.put(100L, "hello map1");
         longStringHashMap.put(101L, "hello map2");
+        longStringHashMap.put(102L, null);
         entity.setLongStringMap(longStringHashMap);
 
         var intStringHashMap = new HashMap<Integer, String>();