mybatis plus selectList

MyBatis Plus is an enhanced version of the MyBatis framework, providing additional features and simplifying the development process. To execute a SELECT query using MyBatis Plus' selectList method, you need to follow these steps:

1. Define a mapper interface: Create an interface that extends the BaseMapper interface provided by MyBatis Plus. This interface will define the methods for performing database operations.

2. Write a SQL query: Use the @Select annotation provided by MyBatis Plus to define the SQL query for selecting records from the database. Alternatively, you can use the QueryWrapper or LambdaQueryWrapper to build dynamic queries.

3. Invoke the selectList method: In your service or controller class, inject the mapper interface and use its selectList method to execute the query. Pass in the necessary parameters, if any, and retrieve the result as a list of objects.

Here's an example of how you can use the selectList method in MyBatis Plus:

// Step 1: Define a mapper interface
public interface UserMapper extends BaseMapper<User> {
    @Select("SELECT * FROM users")
    List<User> getAllUsers();
}

// Step 2: Write a SQL query

// Step 3: Invoke the selectList method
@Autowired
private UserMapper userMapper;

public List<User> getAllUsers() {
    return userMapper.getAllUsers();
}

In this example, we define a UserMapper interface that extends BaseMapper<User>. We define the getAllUsers method with an SQL query using the @Select annotation. Finally, we inject the UserMapper interface and invoke the getAllUsers method to retrieve all users from the database.

Remember to configure MyBatis Plus properly in your application's configuration file and set up the database connection details.