至少使用JDK8版本，请下载JDK8或者更高版本： 下载以及配置JDK环境
因为是第三方插件，所以需要额外的jar包，都在右上角提供了下载：pagehelper-5.1.0-beta2.jar，jsqlparser-1.0.jar
配置插件
在mybatis-config.xml中，添加15-19行的代码，表示开启PageHelper插件
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<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configurationPUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration> <settings>
<!-- 打开延迟加载的开关 -->
<setting name="lazyLoadingEnabled" value="true" />
<!-- 将积极加载改为消息加载即按需加载 -->
<setting name="aggressiveLazyLoading" value="false"/>
</settings>
<typeAliases>
<package name="com.how2java.pojo"/>
</typeAliases>
<plugins>
<plugin interceptor="com.github.pagehelper.PageInterceptor">
</plugin>
</plugins>
<environments default="development">
<environment id="development">
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<property name="driver" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/how2java?characterEncoding=UTF-8"/>
<property name="username" value="root"/>
<property name="password" value="admin"/>
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="com/how2java/pojo/Category.xml"/>
<mapper class="com.how2java.mapper.CategoryMapper"/>
<mapper class="com.how2java.mapper.ProductMapper"/>
</mappers>
</configuration> |
分页查询
查询很有意思，只需要在执行查询所有的调用之前，执行一条语句即可：
PageHelper.offsetPage(0, 5);
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package com.how2java;
import java.io.IOException;
import java.io.InputStream;
import java.util.List;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import com.github.pagehelper.PageHelper;
import com.how2java.pojo.Category;
public class TestMybatis {
public static void main(String[] args) throws IOException, InterruptedException {
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
SqlSession session = sqlSessionFactory.openSession();
PageHelper.offsetPage(0, 5);
List<Category> cs = session.selectList("listCategory");
for (Category c : cs) {
System.out.println(c.getName());
}
session.commit();
session.close();
}
} |
获取总数
通过第31行的代码
就可以获取分页信息，包括总数以及其他的
PageInfo page= new PageInfo<>(cs);
就可以获取分页信息，包括总数以及其他的
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package com.how2java;
import java.io.IOException;
import java.io.InputStream;
import java.util.List;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import com.github.pagehelper.PageHelper;
import com.github.pagehelper.PageInfo;
import com.how2java.pojo.Category;
public class TestMybatis {
public static void main(String[] args) throws IOException, InterruptedException {
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
SqlSession session = sqlSessionFactory.openSession();
PageHelper.offsetPage(0, 5);
List<Category> cs = session.selectList("listCategory");
for (Category c : cs) {
System.out.println(c.getName());
}
PageInfo pageInfo = new PageInfo<>(cs);
System.out.println("总数："+pageInfo.getTotal());
System.out.println(pageInfo);
session.commit();
session.close();
}
} |