How to use pagehelper to query all data

To query all data using the PageHelper plugin, follow the steps below:

1. Add the dependency of PageHelper in the pom.xml file of the project.

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

1. In the configuration file of MyBatis (usually mybatis-config.xml), add the PageHelper plugin configuration.

<plugins>
    <plugin interceptor="com.github.pagehelper.PageInterceptor">
        <!-- 设置数据库类型 -->
        <property name="dialect" value="数据库方言"/>
    </plugin>
</plugins>

1. In Java code, use the PageHelper.startPage method to initiate a pagination query, and then call the method to retrieve all data.

import com.github.pagehelper.PageHelper;
import com.github.pagehelper.PageInfo;

// 开启分页查询，设置页码和每页数据量
PageHelper.startPage(pageNum, pageSize);
// 查询全部数据
List<YourEntity> dataList = yourMapper.selectAll();
// 使用PageInfo对结果进行包装
PageInfo<YourEntity> pageInfo = new PageInfo<>(dataList);

In the code above, pageNum represents the page number to be queried and pageSize represents the amount of data to be displayed per page. YourMapper is a MyBatis Mapper interface that you have defined yourself, with the selectAll method being a method defined in this Mapper interface for querying all data.

1. Finally, use the PageInfo object as needed to obtain pagination information and query results.

// 获取总记录数
long total = pageInfo.getTotal();
// 获取当前页的数据
List<YourEntity> currentPageData = pageInfo.getList();

// 可以根据需要打印分页信息
System.out.println("总记录数：" + total);
System.out.println("当前页码：" + pageInfo.getPageNum());
System.out.println("每页数据量：" + pageInfo.getPageSize());
System.out.println("总页数：" + pageInfo.getPages());

The steps above outline how to use the PageHelper plugin to query all data. Remember to configure and call it according to your own needs.