MyBatis console outputs SQL query information

MyBatis is an open source persistence layer framework that simplifies the development of the data access layer. In actual development, we often need to view the specific SQL statements and parameter information generated by MyBatis when executing SQL queries to facilitate debugging and optimization. This article will introduce how to configure MyBatis to output SQL query information to the console for developers to debug.

First, in the MyBatis configuration file (such as mybatis-config.xml), we need to add the following configuration:

<configuration>
    <!-- 其他配置 -->
    
    <!-- 开启日志输出 -->
    <settings>
        <setting name="logImpl" value="STDOUT_LOGGING"/>
    </settings>
    
    <!-- 配置日志输出级别 -->
    <settings>
        <setting name="logLevel" value="DEBUG"/>
    </settings>
</configuration>

In the above configuration, we set logImpl The value is STDOUT_LOGGING to specify the log output to the console, and the value of logLevel is set to DEBUG to specify the output log level to DEBUG. In this way, MyBatis' SQL query information can be output to the console.

Next, we can output SQL query information by adding annotations to specific Mapper interface methods. For example, the following is an example of the Mapper interface using annotations:

@Mapper
public interface UserMapper {

    @Select("SELECT * FROM user WHERE id = #{id}")
    @Options(statementType = StatementType.STATEMENT)
    User selectUserById(Long id);
}

In the above code, we use the @Select annotation to specify the SQL query statement and pass ${id} to reference parameters. At the same time, we also added @Options(statementType = StatementType.STATEMENT) to specify the use of PreparedStatement to execute SQL statements. After this configuration, MyBatis will output the specific SQL statement and parameter information to the console when executing the SQL query.

Finally, when the application starts, we can add the following code to output the SQL query information of MyBatis:

SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(configuration);
SqlSession sqlSession = sqlSessionFactory.openSession();
UserMapper userMapper = sqlSession.getMapper(UserMapper.class);

User user = userMapper.selectUserById(1L);

Through the above steps, we can see the SQL output by MyBatis on the console Query information, including specifically executed SQL statements and parameter information, helps developers debug and optimize. I hope this article will help you understand how to output SQL query information in MyBatis.

The above is the detailed content of MyBatis console outputs SQL query information. For more information, please follow other related articles on the PHP Chinese website!