MyBatis console displays the SQL execution process

MyBatis console displays the SQL execution process and requires specific code examples

When using MyBatis for database operations, we often need to view the specific execution process of SQL statements. To facilitate debugging and optimization. MyBatis provides a configuration property that can display SQL statements and execution parameters on the console, making it easier for us to track and locate problems. In this article, we will introduce how to configure the console in MyBatis to display the SQL execution process, and attach specific code examples.

Step one: Configure the MyBatis console to display the SQL execution process

In the MyBatis configuration file (usually mybatis-config.xml), we need to set a configuration attribute and open the console Show the SQL execution process. The specific configuration is as follows:

<configuration>
    <settings>
        <setting name="logImpl" value="STDOUT_LOGGING"/>
    </settings>
</configuration>

In the above configuration, we specify the log output to the console by setting the logImpl attribute to STDOUT_LOGGING. In this way, you can see the process of MyBatis executing SQL statements on the console.

Step 2: Write the specific MyBatis Mapper interface and SQL mapping file

Next, let’s write the specific MyBatis Mapper interface and SQL mapping file. Here is a simple example. Suppose we have a user table (user) to store user information. The SQL we want to query user information is as follows:

<!-- UserMapper.xml -->
<mapper namespace="com.example.UserMapper">
    <select id="getUserById" resultType="com.example.User">
        SELECT * FROM user
        WHERE id = #{userId}
    </select>
</mapper>

The corresponding Mapper interface is as follows:

// UserMapper.java
package com.example;

public interface UserMapper {
    User getUserById(Long userId);
}

Step 3: Call the Mapper interface and view the console output

Finally, we call the UserMapper interface and view the output on the console. We can achieve this in the following way:

public class Main {
    public static void main(String[] args) {
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().
            build(Resources.getResourceAsStream("mybatis-config.xml"));
        SqlSession sqlSession = sqlSessionFactory.openSession();

        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        User user = userMapper.getUserById(1L);

        System.out.println(user);

        sqlSession.close();
    }
}

When we run the above code, we will see output similar to the following on the console:

DEBUG - ==>  Preparing: SELECT * FROM user WHERE id = ?
DEBUG - ==>  Parameters: 1(Long)
DEBUG - <==      Total: 1
com.example.User@1234567

The above output shows the MyBatis execution The process of a SQL statement includes the preparation phase of the SQL statement and the parameter passing process. Through this information, we can clearly understand the execution process of SQL statements, which facilitates debugging and optimization.

Summary

Through the introduction of this article, we have learned how to configure the console in MyBatis to display the SQL execution process, and given specific code examples. This can help us better track and locate problems during SQL execution, and improve development efficiency and code quality. I hope this article will be helpful to everyone when developing with MyBatis!

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