How to configure database connection in mybatis

Mybatis configuration database connection method: 1. Specify the data source; 2. Configure the transaction manager; 3. Configure the type processor and mapper; 4. Use environment elements; 5. Configure aliases. Detailed introduction: 1. Specify the data source. In the "mybatis-config.xml" file, you need to configure the data source. The data source is an interface, which provides a database connection; 2. Configure the transaction manager to ensure the normality of database transactions. For processing, you also need to configure the transaction manager; 3. Configure the type processor and mapper, etc.

The operating system for this tutorial: Windows 10 system, DELL G3 computer.

MyBatis is an excellent persistence layer framework that supports customized SQL, stored procedures and advanced mapping. In MyBatis, configuring the database connection is a very important first step. The following will introduce in detail how to configure MyBatis database connection.

First, you need to specify the database connection information in the MyBatis configuration file (usually mybatis-config.xml). This file is usually located in the project's resources directory.

1. Specify the data source

In the mybatis-config.xml file, you need to configure the data source. A data source is an interface that provides a database connection. The following is an example of using HikariCP as a data source:

<configuration>  
  <!-- 其他配置项 -->  
    
  <!-- 数据源配置 -->  
  <dataSource type="com.zaxxer.hikari.HikariDataSource">  
    <!-- JDBC 驱动类名 -->  
    <property name="driverClassName" value="com.mysql.jdbc.Driver"/>  
    <!-- 数据库连接 URL -->  
    <property name="url" value="jdbc:mysql://localhost:3306/mydatabase"/>  
    <!-- 数据库用户名 -->  
    <property name="username" value="myuser"/>  
    <!-- 数据库密码 -->  
    <property name="password" value="mypassword"/>  
  </dataSource>  
    
  <!-- 其他配置项 -->  
</configuration>

2. Configuring the transaction manager

In order to ensure the normal processing of database transactions, you also need to configure the transaction manager . You can choose org.springframework.jdbc.datasource.DataSourceTransactionManager provided by Spring as the transaction manager:

<transactionManager type="org.springframework.jdbc.datasource.DataSourceTransactionManager"/>

3. Configure type processor and mapper

You also Type processors and mappers can be configured to customize data conversion and SQL mapping. For example, you can configure org.mybatis.typehandlers.StringTypeHandler to handle string type fields:

<typeHandlers>  
  <typeHandler handler="org.mybatis.typehandlers.StringTypeHandler"/>  
</typeHandlers>

4. Use the environment element

Use the 0fd6d6689885ba558ffb501b23874339 element Different database connection information can be configured for different environments (development, testing, production, etc.). This is very useful for the isolation of development and production environments:

<environments default="development">  
  <environment id="development">  
    <transactionManager type="JDBC"/>  
    <dataSource type="POOLED">  
      <!-- 开发环境的数据库连接信息 -->  
    </dataSource>  
  </environment>  
  <environment id="production">  
    <transactionManager type="JDBC"/>  
    <dataSource type="UNPOOLED">  
      <!-- 生产环境的数据库连接信息 -->  
    </dataSource>  
  </environment>  
</environments>

5. Configure aliases

In order to simplify the code, you can configure aliases for Java classes, so in the mapping file You can use the alias directly instead of the complete class name:

<typeAliases>  
  <typeAlias alias="User" type="com.example.User"/>  
</typeAliases>

After completing the above configuration, MyBatis will be able to interact with the database based on the configured database connection information. Please make sure that your database driver is added to the project's dependencies and that all necessary configuration items are set correctly.

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