How to use mybatis paging plug-in

How to use the mybatis paging plug-in: 1. Add the paging plug-in dependency; 2. Configure the paging plug-in; 3. Configure the parameters of the paging plug-in; 4. Write the paging query code; 5. Call paging in Service or Controller Query method. Detailed introduction: 1. To add paging plug-in dependencies, first ensure that the relevant dependencies of MyBatis have been added to the project, and then add the dependencies of the MyBatis paging plug-in; 2. Configure the paging plug-in, in the MyBatis configuration file, add the paging plug-in configuration, etc. .

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

MyBatis paging plug-in is a plug-in used to implement paging function in MyBatis. It can simplify the writing of paging queries and improve development efficiency. The following is how to use the MyBatis paging plug-in:

1. Add paging plug-in dependencies

First, make sure that the relevant dependencies of MyBatis have been added to your project. Then, add the dependency of the MyBatis paging plugin. If you are using Maven, you can add the following dependency in the pom.xml file:

<dependency>  
    <groupId>com.github.pagehelper</groupId>  
    <artifactId>pagehelper</artifactId>  
    <version>最新版本</version>  
</dependency>

Please note that you need to replace the "latest version" in the tag with the actual latest version number.

2. Configure the paging plug-in

In the MyBatis configuration file (usually mybatis-config.xml), add the configuration of the paging plug-in. Find the tag and add the following content in it:

<plugins>  
    <plugin interceptor="com.github.pagehelper.PageInterceptor">  
        <!-- 分页插件的配置项 -->  
    </plugin>  
</plugins>

3. Configure the parameters of the paging plug-in

In the configuration of the paging plug-in, you can set Some parameters to control the behavior of paging. The following are some commonly used configuration parameters:

• helperDialect: Specify the database dialect used, such as mysql, oracle, etc.

• offsetAsPageNum: Whether to treat the offset in SQL as a page number. Default is false.

• offsetAsPageSize: Whether to treat the offset in SQL as the number of records displayed per page. Default is false.

• countSqlWithTotalCount: Whether to calculate the total number of records when executing SQL. Default is false.

• reasonable: Whether to enable smart paging. Defaults to true.

• supportMethodsArguments: Whether to support paging query using method parameters. Defaults to true.

• params: Custom paging parameters, you can pass in an object containing paging parameters.

4. Write paging query code

After using the MyBatis paging plug-in, you can write paging query code in the Mapper interface or XML mapping file . The following is an example:

Suppose you have an entity class named User, and a corresponding Mapper interface UserMapper:

public interface UserMapper {  
    List<User> getUsersByPage(PageHelper.Page page);  
}

In the getUsersByPage method, you can call the PageHelper.startPage method to Set the paging parameters and then perform the query operation. The query results will include information such as the data of the current page and the total number of records. For example:

5. Call the paging query method in Service or Controller

In your Service or Controller, you can call the paging query method in Mapper, and Pass pagination parameters. For example:

@Service  
public class UserService {  
    @Autowired  
    private UserMapper userMapper;  
      
    public List<User> getUsersByPage(int pageNum, int pageSize) {  
        PageHelper.startPage(pageNum, pageSize); // 设置分页参数  
        List<User> users = userMapper.getUsersByPage(null); // 执行分页查询操作  
        return users; // 返回当前页的数据列表和总记录数等信息  
    }  
}

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