MyBatis Plus is an open source persistence framework based on MyBatis. It simplifies data persistence operations by automatically generating SQL statements and providing rich addition, deletion, modification and query functions.
MyBatis Plus not only retains the advantages of MyBatis, but also provides more convenient functions and tools, which greatly improves development efficiency.
This article will introduce the characteristics, core functions and application of MyBatis Plus in actual projects.
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1. Features of MyBatis Plus
- Quick start: MyBatis Plus provides a wealth of predefined CRUD (creation, deletion, modification, query) methods, allowing developers to quickly start and complete basic data operations.
- Concise code: MyBatis Plus greatly simplifies the writing of SQL statements through annotations and built-in methods, reduces code redundancy, and improves code readability and maintainability.- Automatically generate SQL: MyBatis Plus has a built-in code generator, which can automatically generate entity classes, Mapper interfaces, and XML mapping files according to the database table structure, eliminating the trouble of handwriting a large number of SQL statements.
- Condition builder: MyBatis Plus provides a powerful condition builder, which can flexibly combine conditions and support dynamic condition queries, which greatly improves the flexibility and scalability of queries.
- Paging query: MyBatis Plus has a built-in paging query function, which supports paging methods of various databases, and is convenient for developers to perform paging query operations.
2. The core functions of MyBatis Plus
- Entity class generation: The code generator of MyBatis Plus can automatically generate entity classes based on database tables. Developers only need to simply configure table names and field mappings to generate entity classes that conform to the JavaBean specification.
- Mapper interface generation: MyBatis Plus will generate a corresponding Mapper interface for each entity class, and can complete basic CRUD operations without manually writing SQL statements.
- Condition builder: MyBatis Plus provides a Wrapper class for splicing various conditions, including equal to, greater than, less than, fuzzy queries, etc. Developers can dynamically assemble conditions as needed to achieve flexible query operations.
- Paging query: The paging plug-in of MyBatis Plus can automatically process paging query, and supports multiple database paging methods, such as MySQL's limit, Oracle's rownum, etc., which is very convenient to use.
3. Application of MyBatis Plus in actual projects
- add dependencies
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-boot-starter</artifactId>
<version>latest_version</version>
</dependency>
- Create entity classes
public class User {
private Long id;
private String username;
private String email;
// ... 省略getter和setter
}
- Create the Mapper interface
@Mapper
public interface UserMapper extends BaseMapper<User> {
}
- Data manipulation with MyBatis Plus
@Service
public class UserService {
@Autowired
private UserMapper userMapper;
public List<User> getAllUsers() {
return userMapper.selectList(null);
}
public User getUserById(Long id) {
return userMapper.selectById(id);
}
public int addUser(User user) {
return userMapper.insert(user);
}
public int updateUser(User user) {
return userMapper.updateById(user);
}
public int deleteUser(Long id) {
return userMapper.deleteById(id);
}
}
MyBatis Plus is a powerful and simple data persistence framework. Through its rich functions and tools, data operations become efficient, concise and flexible. MyBatis Plus can not only automatically generate SQL statements, but also provides powerful functions such as condition builder and pagination query, which meet most data persistence requirements. In actual projects, reasonable use of MyBatis Plus can greatly improve development efficiency, reduce the amount of code, and make data persistence operations simpler and more elegant.