Issue with MapStruct and mapping using Java Spring Boot

Question

I'm trying to develop an API using MapStruct in my "Category" controller, but the console is returning the error:

***************************
APPLICATION FAILED TO START
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Description:

Parameter 1 of constructor in com.api.business_products_management.controllers.CategoryController required a bean of type 'com.api.business_products_management.mappers.CategoryMapper' that could not be found.


Action:

Consider defining a bean of type 'com.api.business_products_management.mappers.CategoryMapper' in your configuration.


Process finished with exit code 1

Here the controller

package com.api.business_products_management.controllers;

import com.api.business_products_management.dtos.CategoryDto;
import com.api.business_products_management.mappers.CategoryMapper;
import com.api.business_products_management.models.CategoryModel;
import com.api.business_products_management.services.CategoryService;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import jakarta.validation.Valid;
import org.apache.catalina.LifecycleState;
import org.springframework.beans.BeanUtils;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;

import java.util.List;

@RestController
@CrossOrigin(origins = "*", maxAge = 3600)
@RequestMapping("/category")
public class CategoryController {

    final CategoryService categoryService;
    final CategoryMapper categoryMapper;

    public CategoryController(CategoryService categoryService, CategoryMapper categoryMapper) {
        this.categoryService = categoryService;
        this.categoryMapper = categoryMapper;

    }

    @PostMapping
    public ResponseEntity<Object> saveCategory (@RequestBody @Valid CategoryDto categoryDto) {
        if (categoryService.existsByName(categoryDto.getName())) {
            return ResponseEntity.status(HttpStatus.CONFLICT).body("Conflict: Category already exists! ");
        }
        var categoryModel = categoryMapper.toCategoryModel(categoryDto);
        return ResponseEntity.status(HttpStatus.CREATED).body(categoryService.save(categoryModel));
    }
    @GetMapping
    public ResponseEntity<List<CategoryModel>> getAllCategories() {
        return ResponseEntity.status(HttpStatus.OK).body(categoryService.findAll());
    }
}

my CategoryMapper interface

package com.api.business_products_management.mappers;

import com.api.business_products_management.dtos.CategoryDto;
import com.api.business_products_management.models.CategoryModel;
import org.mapstruct.Mapper;
import org.springframework.stereotype.Component;

@Component
@Mapper(componentModel = "spring")
public interface CategoryMapper {
    CategoryModel toCategoryModel(CategoryDto dto);
}

My pom.xml

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>3.0.2</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.api</groupId>
    <artifactId>business_products_management</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>business_products_management</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>17</java.version>
        <org.mapstruct.version>1.4.2.Final</org.mapstruct.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-security</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-validation</artifactId>
        </dependency>
        <dependency>
            <groupId>org.postgresql</groupId>
            <artifactId>postgresql</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.mapstruct</groupId>
            <artifactId>mapstruct</artifactId>
            <version>1.4.2.Final</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

As it says in the error, I'm already declaring the correct mapping in my constructor along with the interface, I can't identify the reason for this error

Answer 1

As I said in the comments, you need to add the mapstruct annotation processor.

You're missing the

  <plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-compiler-plugin</artifactId>
    <version>3.6.0</version>
    <configuration>
      <source>${java.version}</source>
      <target>${java.version}</target>
      <annotationProcessorPaths>
         <path>
           <groupId>org.mapstruct</groupId>
           <artifactId>mapstruct-processor</artifactId>
           <version>${org.mapstruct.version}</version>
         </path>
      </annotationProcessorPaths>
    </configuration>
  </plugin>

section.