MyBatis Plus Database Connection Guide

1 year ago
Emily Johnson
2 minutes

MyBatis Plus is an ORM framework based on MyBatis, which simplifies the process of connecting to and operating with databases. Below are the steps to connect to a database:

Add dependency: Add MyBatis Plus dependency to the project’s pom.xml file. You can search for mybatis-plus-boot-starter in the Maven Central Repository and add it to the project dependencies.

<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-boot-starter</artifactId>
    <version>最新版本</version>
</dependency>

Configure data source: Configure a data source in the project’s configuration file, using any data source that conforms to the JDBC specification, such as Druid or HikariCP.

3. Setting up MyBatis Plus: Add configuration options for MyBatis Plus in the project’s configuration file.

# 数据库类型
spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
# 数据库连接信息
spring.datasource.url=jdbc:mysql://localhost:3306/mybatisplus?useUnicode=true&characterEncoding=utf8&autoReconnect=true&useSSL=false
spring.datasource.username=root
spring.datasource.password=123456
# 数据库驱动
spring.datasource.driver-class-name=com.mysql.jdbc.Driver

# MyBatis Plus 配置项
# 指定 MyBatis Plus 的 mapper 扫描路径
mybatis-plus.mapper-locations=classpath*:mapper/**/*.xml
# 实体类扫描路径
mybatis-plus.type-aliases-package=com.example.entity
# MyBatis Plus 日志配置
mybatis-plus.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl

Create entity classes: create classes corresponding to database tables, and use annotations such as @TableName to specify the table name and @TableField to specify the field names in the database.

@Data
@TableName("user")
public class User {
    @TableId(type = IdType.AUTO)
    private Long id;
    private String name;
    private Integer age;
    private String email;
}

Write the Mapper interface: Create a Mapper interface for the corresponding entity class. By inheriting the BaseMapper interface, you can easily access common database operations methods.

public interface UserMapper extends BaseMapper<User> {

}

Usage: Inject the corresponding Mapper interface where database operations are needed, and you can use the database operation methods provided by MyBatis Plus.

@Service
public class UserServiceImpl implements UserService {
    @Autowired
    private UserMapper userMapper;

    @Override
    public User getUserById(Long userId) {
        return userMapper.selectById(userId);
    }

    @Override
    public List<User> getUserList() {
        return userMapper.selectList(null);
    }

    @Override
    public int addUser(User user) {
        return userMapper.insert(user);
    }

    @Override
    public int updateUser(User user) {
        return userMapper.updateById(user);
    }

    @Override
    public int deleteUser(Long userId) {
        return userMapper.deleteById(userId);
    }
}

These are the fundamental steps for connecting to a database using MyBatis Plus: configuring the data source and MyBatis Plus settings, and then using the corresponding Mapper interface to perform database operations.

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