dozer-extra-converters

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Additional custom converters for the Dozer object mapping framework (dozer-core 7.x). The converters cover Boolean, fastjson2 JSON, BigDecimal and BigInteger <-> String conversions.

Table of Contents

• 1. Project Overview
• 2. Features & Status
• 3. Requirements & Compatibility
• 4. Architecture & Modules
• 5. Installation
• 6. Quick Start
• 7. Configuration
• 8. Core Usage / API
• 9. Testing & Build
• 10. Versioning & Branches
• 11. Contributing & License

1. Project Overview

dozer-extra-converters (project description: Dozer Extra) is a small companion library for the Dozer mapping framework. It ships ready-made DozerConverter implementations for common String-related type conversions that are not covered out of the box, so they can be registered into a Dozer mapping without writing converter boilerplate.

What it is	What it is not
A set of custom converters for dozer-core 7.x	A standalone mapping framework (it builds on Dozer)
Thin, dependency-light utility code	A Spring Boot starter (no auto-configuration)

Typical use cases:

Use case	Why it helps
Mapping Boolean fields to/from String values	BooleanStringConverter delegates to Apache Commons BeanUtils BooleanConverter
Mapping fastjson2 JSONObject / JSONArray to/from String	JSONObjectStringConverter / JSONArrayStringConverter (fastjson2 2.x)
Mapping BigDecimal / BigInteger to/from String	BigDecimalStringConverter / BigIntegerStringConverter preserve plain string forms
Spring environments using Dozer	dozer-spring4 integration artifact is declared as a compile dependency

Project status: active development.

Note: in the current feature/2.0.x snapshot the repository tree carries the build configuration (pom.xml, LICENSE, Maven wrapper); the converter sources are versioned in this repository's git history and on the master branch, and are described below as the artifact's public API.

2. Features & Status

Feature	Status	Notes
BooleanStringConverter	Available	Boolean <-> String, backed by org.apache.commons.beanutils.converters.BooleanConverter
JSONObjectStringConverter	Available	fastjson2 JSONObject <-> String
JSONArrayStringConverter	Available	fastjson2 JSONArray <-> String
BigDecimalStringConverter	Available	BigDecimal <-> String (in converters.number)
BigIntegerStringConverter	Available	BigInteger <-> String (in converters.number)
dozer-spring4 integration	Available	dozer-spring4 7.0.0 declared as compile dependency
Unit tests	Minimal	Test sources exist in the repository lineage (CodecAndCryptoTest)
CI pipeline	Not configured	No CI workflow files in the repository

3. Requirements & Compatibility

Requirement	Version
JDK	8
Maven	3.0+
dozer-core	7.0.0 (com.github.dozermapper)
dozer-spring4	7.0.0
fastjson2	2.0.53
slf4j-api	2.0.18
Lombok	provided scope (annotation processing at build time)

Version lines

Branch	JDK	Version pattern
feature/1.0.x	JDK 8	1.0.x.*
feature/2.0.x	JDK 17	2.0.x.*
feature/3.0.x	JDK 21	3.0.x.*

4. Architecture & Modules

  Source value          custom converter               target value
 (Boolean / JSON /   ->  extends                       (String / JSON /
  BigDecimal /            DozerConverter<A,B>            BigDecimal /
  BigInteger)             convertFrom / convertTo        BigInteger)
        |                        |                          |
        +----------> Dozer Mapper (dozer-core 7.0) <--------+
                     registered via mapping definition
                          (XML custom-converters
                            or mapper API)

Single module, jar packaging:

Module	Responsibility
dozer-extra-converters	One jar containing all extra converters (base package com.github.dozermapper.extra.converters, numeric converters under .number)

5. Installation

Maven

<dependency>
    <groupId>io.github.easy4j</groupId>
    <artifactId>dozer-extra-converters</artifactId>
    <version>2.0.x.x.20260630-SNAPSHOT</version>
</dependency>

Gradle

implementation 'io.github.easy4j:dozer-extra-converters:2.0.x.x.20260630-SNAPSHOT'

Availability: the artifact is published to the Aliyun private Maven repository and distributed through GitHub Releases; it has not yet been published to Maven Central.

6. Quick Start

Converters are plain classes; they can be used directly or registered into a Dozer mapping.

import com.alibaba.fastjson2.JSONObject;
import com.github.dozermapper.extra.converters.BooleanStringConverter;
import com.github.dozermapper.extra.converters.JSONObjectStringConverter;

BooleanStringConverter boolConv = new BooleanStringConverter();
String flag = boolConv.convertTo(Boolean.TRUE, null);            // "true"
Boolean restored = boolConv.convertFrom("true", null);           // true

JSONObjectStringConverter jsonConv = new JSONObjectStringConverter();
String json = jsonConv.convertTo(JSONObject.parseObject("{\"k\":1}"), null); // {"k":1}
JSONObject obj = jsonConv.convertFrom("{\"k\":1}", null);        // JSONObject{k:1}

Expected results: "true", true, {"k":1}, and a parsed JSONObject respectively.

7. Configuration

There is no runtime configuration: the converters are plain DozerConverter implementations and are wired into Dozer through its custom-converter registration mechanism (mapping XML custom-converters or the mapper API). No configuration files or properties are read by this library.

Assumption: the exact registration syntax follows the dozermapper 7.x documentation; verify the schema URL and element names against the Dozer version you use.

8. Core Usage / API

All converters extend com.github.dozermapper.core.DozerConverter<A, B> and implement the two abstract methods:

• A convertFrom(B source, A destination) — converts from the source side to A
• B convertTo(A source, B destination) — converts from A to the target side

Converter class	Generic pair
com.github.dozermapper.extra.converters.BooleanStringConverter	Boolean <-> String
com.github.dozermapper.extra.converters.JSONObjectStringConverter	JSONObject <-> String
com.github.dozermapper.extra.converters.JSONArrayStringConverter	JSONArray <-> String
com.github.dozermapper.extra.converters.number.BigDecimalStringConverter	BigDecimal <-> String
com.github.dozermapper.extra.converters.number.BigIntegerStringConverter	BigInteger <-> String

Example with the numeric converters:

import com.github.dozermapper.extra.converters.number.BigDecimalStringConverter;

BigDecimalStringConverter conv = new BigDecimalStringConverter();
String s = conv.convertTo(new BigDecimal("12345.6700"), null); // "12345.6700" (toPlainString)
BigDecimal d = conv.convertFrom("12345.67", null);             // BigDecimal("12345.67")

9. Testing & Build

./mvnw clean verify        # compile, run tests, generate coverage report
./mvnw clean install       # install into the local repository

• Coverage is measured with the JaCoCo Maven plugin (prepare-agent / report / check bound to verify); the configured target is 90% line coverage, currently with haltOnFailure=false.
• The pom keeps the Surefire plugin configuration (including the skip flag) from the release workflow — pass -DskipTests=false when you explicitly want to execute tests. Assumption: behavior may be adjusted in future commits.
• The release profile assembles GPG signing + sources + Javadoc + deployment (./mvnw -Prelease clean deploy); the central profile targets the Maven Central Portal publisher.

10. Versioning & Branches

Three parallel version lines are maintained in this repository:

Branch	JDK	Version pattern	Notes
feature/1.0.x	JDK 8	1.0.x.*	Current line; baseline for legacy applications
feature/2.0.x	JDK 17	2.0.x.*	Modern line
feature/3.0.x	JDK 21	3.0.x.*	Latest line

Maintenance strategy: the 1.0.x line receives bug fixes and dependency updates while JDK 8 remains a supported baseline; feature development primarily targets the 2.0.x / 3.0.x lines.

11. Contributing & License

Contributions are welcome — open an issue or submit a pull request against the matching version-line branch (feature/2.0.x for JDK 17 changes).

This project is licensed under the Apache License, Version 2.0. See the LICENSE file in the repository root for details.