`InvalidDefinitionException: Java 8 date/time type java.time.LocalDateTime…` when calling `mapper.createObjectNode().putPOJO` in fasterxml jackson-databind

Explanation of the problem

The code throws a “java.lang.RuntimeException: com.fasterxml.jackson.databind.exc.InvalidDefinitionException: Java 8 date/time type java.time.LocalDateTime not supported by default: add Module ‘com.fasterxml.jackson.datatype:jackson-datatype-jsr310’ to enable handling” exception when run. The exception originates from the “com.fasterxml.jackson.databind.node.InternalNodeMapper.nodeToPrettyString” method and is caused by an “com.fasterxml.jackson.databind.exc.InvalidDefinitionException: Java 8 date/time type java.time.LocalDateTime not supported by default”.

The code imports the “com.fasterxml.jackson.datatype.jsr310.JavaTimeModule” module and creates an “ObjectMapper” with the “JsonMapper.builder().addModule(new JavaTimeModule()).build()” statement. The code then creates an “ObjectNode” and attempts to add a “LocalDateTime” object to it with the “putPOJO” method.

The build.gradle file specifies a dependency on “com.fasterxml.jackson:jackson-bom:2.12.5” with other unspecified dependencies. The code fails with the exception using version 2.13.0-rc2 but works as expected with version 2.11.4.

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Problem solution for`InvalidDefinitionException: Java 8 date/time type java.time.LocalDateTime…` when calling `mapper.createObjectNode().putPOJO`

The error message “InvalidDefinitionException: Java 8 date/time type java.time.LocalDateTime…” when calling mapper.createObjectNode().putPOJO indicates that the java.time.LocalDateTime type is not supported by the ObjectMapper class. To solve this issue, you can use a custom serializer to convert the LocalDateTime object to a string representation before serializing it to a JSON string.

Here’s an example of how you can implement a custom serializer in Jackson, a popular Java library for JSON processing:

public class LocalDateTimeSerializer extends JsonSerializer<LocalDateTime> {
    @Override
    public void serialize(LocalDateTime value, JsonGenerator gen, SerializerProvider serializers) throws IOException {
        gen.writeString(value.format(DateTimeFormatter.ISO_LOCAL_DATE_TIME));
    }
}

To use this custom serializer, you need to annotate the LocalDateTime field with @JsonSerialize and specify the custom serializer class. For example:

class MyPojo {
    @JsonSerialize(using = LocalDateTimeSerializer.class)
    private LocalDateTime dateTime;

    // other fields, constructors, getters, setters
}

With these changes, you should be able to successfully serialize the LocalDateTime object to a JSON string using the mapper.createObjectNode().putPOJO method.

Other popular problems with fasterxml jackson-databind

A brief introduction to fasterxml jackson-databind

Jackson-databinding is a popular library for Java developers that provides fast and easy-to-use data binding between JSON and Java objects. The library is based on the Jackson JSON processor and uses annotations and interfaces to control the serialization and deserialization process. This technical style allows developers to focus on the business logic of their applications, rather than worrying about the data binding process.

Jackson-databinding offers a number of features and customization options to meet the needs of different applications. For example, the library provides annotations to control the serialization of individual properties or entire objects, as well as the ability to write custom serialization and deserialization logic. It also supports a number of data formats such as JSON, XML, and YAML, making it easy for developers to switch between formats as needed. Additionally, Jackson-databinding offers flexible configuration options that allow developers to fine-tune the behavior of the library to meet the specific needs of their applications.

Most popular use cases for fasterxml jackson-databind

1. Jackson-databind is a Java library used for data-binding, which means converting Java objects to JSON and vice-versa. It is a part of the Jackson library and works seamlessly with other Jackson components.
2. Jackson-databind provides a rich set of annotations that can be used to control the serialization and deserialization process, including specifying the names of properties, ignoring properties, and handling complex data structures such as nested objects and collections.
3. To use Jackson-databind, one can simply create an instance of the ObjectMapper class and use its readValue and writeValueAsString methods to convert Java objects to JSON and vice-versa. For example, consider the following code block:

import com.fasterxml.jackson.databind.ObjectMapper;

public class Main {
    public static void main(String[] args) throws Exception {
        ObjectMapper mapper = new ObjectMapper();
        Person person = new Person("John", "Doe", 30);
        String json = mapper.writeValueAsString(person);
        System.out.println(json);
    }
}

class Person {
    private String firstName;
    private String lastName;
    private int age;
    // constructor, getters, and setters
}