Using Module for DateTime Extension.

jr-extension-datetime/pom.xml

@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <parent>
+        <groupId>com.fasterxml.jackson.jr</groupId>
+        <artifactId>jackson-jr-parent</artifactId>
+        <version>2.17.0-rc1-SNAPSHOT</version>
+    </parent>
+
+    <artifactId>jr-extension-datetime</artifactId>
+
+    <properties>
+        <maven.compiler.source>20</maven.compiler.source>
+        <maven.compiler.target>20</maven.compiler.target>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    </properties>
+    <dependencies>
+        <dependency>
+            <groupId>com.fasterxml.jackson.jr</groupId>
+            <artifactId>jackson-jr-objects</artifactId>
+        </dependency>
+    </dependencies>
+
+</project>

jr-extension-datetime/src/main/java/com/fasterxml/jackson/jr/extension/datetime/JacksonLocalDateTimeExtension.java

@@ -0,0 +1,11 @@
+package com.fasterxml.jackson.jr.extension.datetime;
+
+import com.fasterxml.jackson.jr.ob.JacksonJrExtension;
+import com.fasterxml.jackson.jr.ob.api.ExtensionContext;
+
+public class JacksonLocalDateTimeExtension extends JacksonJrExtension {
+    @Override
+    protected void register(ExtensionContext ctxt) {
+        ctxt.insertProvider(new LocalDateTimeReaderWriterProvider());
+    }
+}

jr-extension-datetime/src/main/java/com/fasterxml/jackson/jr/extension/datetime/LocalDateTimeReaderWriterProvider.java

@@ -0,0 +1,21 @@
+package com.fasterxml.jackson.jr.extension.datetime;
+
+import com.fasterxml.jackson.jr.ob.api.ReaderWriterProvider;
+import com.fasterxml.jackson.jr.ob.api.ValueReader;
+import com.fasterxml.jackson.jr.ob.api.ValueWriter;
+import com.fasterxml.jackson.jr.ob.impl.JSONReader;
+import com.fasterxml.jackson.jr.ob.impl.JSONWriter;
+
+import java.time.LocalDateTime;
+
+public class LocalDateTimeReaderWriterProvider extends ReaderWriterProvider {
+    @Override
+    public ValueReader findValueReader(JSONReader readContext, Class<?> type) {
+        return type.equals(LocalDateTime.class) ? new LocalDateTimeValueReader() : null;
+    }
+
+    @Override
+    public ValueWriter findValueWriter(JSONWriter writeContext, Class<?> type) {
+        return type.equals(LocalDateTime.class) ? new LocalDateTimeValueWriter() : null;
+    }
+}

jr-extension-datetime/src/main/java/com/fasterxml/jackson/jr/extension/datetime/LocalDateTimeValueReader.java

@@ -0,0 +1,20 @@
+package com.fasterxml.jackson.jr.extension.datetime;
+
+import com.fasterxml.jackson.core.JsonParser;
+import com.fasterxml.jackson.jr.ob.api.ValueReader;
+import com.fasterxml.jackson.jr.ob.impl.JSONReader;
+
+import java.io.IOException;
+import java.time.LocalDateTime;
+import java.time.format.DateTimeFormatter;
+
+public class LocalDateTimeValueReader extends ValueReader {
+    public LocalDateTimeValueReader() {
+        super(LocalDateTime.class);
+    }
+
+    @Override
+    public Object read(JSONReader reader, JsonParser p) throws IOException {
+        return LocalDateTime.parse(p.getText(), DateTimeFormatter.ISO_LOCAL_DATE_TIME);
+    }
+}

jr-extension-datetime/src/main/java/com/fasterxml/jackson/jr/extension/datetime/LocalDateTimeValueWriter.java

@@ -0,0 +1,22 @@
+package com.fasterxml.jackson.jr.extension.datetime;
+
+import com.fasterxml.jackson.core.JsonGenerator;
+import com.fasterxml.jackson.jr.ob.api.ValueWriter;
+import com.fasterxml.jackson.jr.ob.impl.JSONWriter;
+
+import java.io.IOException;
+import java.time.LocalDateTime;
+import java.time.format.DateTimeFormatter;
+
+public class LocalDateTimeValueWriter implements ValueWriter {
+    @Override
+    public void writeValue(JSONWriter context, JsonGenerator g, Object value) throws IOException {
+        String localDateTimeString = ((LocalDateTime) value).format(DateTimeFormatter.ISO_LOCAL_DATE_TIME);
+        context.writeValue(localDateTimeString);
+    }
+
+    @Override
+    public Class<?> valueType() {
+        return LocalDateTime.class;
+    }
+}

pom.xml

@@ -26,6 +26,7 @@
     <module>jr-stree</module>
     <module>jr-annotation-support</module>
     <module>jr-all</module>
+    <module>jr-extension-datetime</module>
   </modules>
 
   <url>https://github.com/FasterXML/jackson-jr</url>