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(); }} |