Configuration Setup

Establish database connectivity and tune the connection pool via application.yml. The following excerpt demonstrates HikariCP parameter optimization alongside MyBatis scanning direcitves.

server:
  port: 8080

spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://db-server:3306/data_store?serverTimezone=UTC&useUnicode=true&characterEncoding=UTF-8&useSSL=false
    username: admin
    password: secure_pass_456
    hikari:
      validation-timeout: 3000
      connection-timeout: 30000
      idle-timeout: 600000
      minimum-idle: 5
      maximum-pool-size: 10
      max-lifetime: 1800000
      connection-test-query: SELECT 1

mybatis:
  type-aliases-package: com.demo.persistence.model
  mapper-locations: classpath:mapper/*Dao.xml

Application Initialization

The bootstrap class must instruct Spring to locate DAO interfaces. Applying @MapperScan eliminates the need for individual @Mapper annotations on each repository.

package com.demo;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@MapperScan("com.demo.persistence.dao")
@SpringBootApplication
public class PersistenceBootstrapper {
    public static void main(String[] args) {
        SpringApplication.run(PersistenceBootstrapper.class, args);
    }
}

Persistent Model Definition

Define the domain object that maps to the underlying table. An explicit alias ensures accurate result set mapping without fully qualified class references.

package com.demo.persistence.model;

import lombok.Data;
import org.apache.ibatis.type.Alias;

@Data
@Alias("ArticleNode")
public class ArticleModel {
    private String recordId;
    private String heading;
    private String bodyContent;
}

Data Access Layer

Declare the abstraction for data base interactions followed by the executable SQL definition.

package com.demo.persistence.dao;

import com.demo.persistence.model.ArticleModel;
import org.springframework.stereotype.Component;

@Component
public interface ArticleDao {
    ArticleModel fetchRecord(String recordId);
}

Corresponding SQL mapping:

<?xml version="1.0" encoding="UTF-8" ?>

<mapper namespace="com.demo.persistence.dao.ArticleDao">
    <select id="fetchRecord" resultType="ArticleNode">
        SELECT record_id, heading, body_content 
        FROM articles 
        WHERE record_id = #{recordId}
    </select>
</mapper>

Service Layer Implementation

Encapsulate data operations behind a business contract. Constructor injection promotes testability and explicit dependencies.

package com.demo.business.service;

import com.demo.persistence.model.ArticleModel;

public interface ArticleService {
    ArticleModel retrieveById(String recordId);
}

package com.demo.business.service.impl;

import com.demo.persistence.dao.ArticleDao;
import com.demo.persistence.model.ArticleModel;
import com.demo.business.service.ArticleService;
import org.springframework.stereotype.Service;

@Service
public class DefaultArticleService implements ArticleService {
    private final ArticleDao articleDao;

    public DefaultArticleService(ArticleDao articleDao) {
        this.articleDao = articleDao;
    }

    @Override
    public ArticleModel retrieveById(String recordId) {
        return articleDao.fetchRecord(recordId);
    }
}

REST Controller Exposure

Expose the retrieval workflow through HTTP endpoints. Path variables simplify request routing.

package com.demo.web.controller;

import com.demo.business.service.ArticleService;
import com.demo.persistence.model.ArticleModel;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class ArticleController {
    private final ArticleService articleService;

    public ArticleController(ArticleService articleService) {
        this.articleService = articleService;
    }

    @GetMapping("/articles/{id}")
    public ArticleModel getArticle(@PathVariable String id) {
        return articleService.retrieveById(id);
    }
}