How to use MyBatis

2 years ago
Olivia Parker
3 minutes

MyBatis is a persistence framework for the Java programming language that helps developers streamline database operations. Here are the basic steps for using MyBatis:

1. Add Dependency: Add MyBatis dependency in the project’s build file (such as Maven’s pom.xml). For example:

<dependency>
    <groupId>org.mybatis</groupId>
    <artifactId>mybatis</artifactId>
    <version>3.x.x</version>
</dependency>

Set up data source: Configure database connection information and data source in the project’s configuration file. Typically, these configurations are located in the `mybatis-config.xml` file and include database connection information, mappers, and other MyBatis configuration options.

Create a Java interface that defines the methods for interacting with the database, with each method corresponding to a SQL query or update operation.

Write mapper XML files: Write an XML file for each mapper interface that contains SQL statements for interacting with the database and mapping rules for the results. The XML file typically has the same name as the mapper interface but with a .xml extension.

Configure MyBatis: Set up MyBatis in the mybatis-config.xml file, such as configuring the data source and specifying the location of mapper files.

6. Utilizing MyBatis involves loading configuration files, creating a SqlSessionFactory, and utilizing SqlSession in the code. The SqlSessionFactory is a thread-safe factory class used for creating SqlSession objects, which are then used to execute SQL operations.

Once the above steps have been completed, you can use MyBatis to perform database operations. Here is an example of querying data using MyBatis:

// 加载 MyBatis 配置文件
InputStream inputStream = Resources.getResourceAsStream("mybatis-config.xml");
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
// 创建 SqlSession
SqlSession sqlSession = sqlSessionFactory.openSession();
try {
    // 获取映射器接口的实例
    MyMapper mapper = sqlSession.getMapper(MyMapper.class);
    // 调用映射器接口中的方法执行查询
    List<MyObject> objects = mapper.getAllObjects();
    // 处理查询结果
    for (MyObject object : objects) {
        System.out.println(object);
    }
} finally {
    // 关闭 SqlSession
    sqlSession.close();
}

This is just a simple example, but MyBatis also offers more features and flexibility, such as parameter passing, dynamic SQL, transaction management, and so on.

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