mybatis扩展之使用PageHelper插件进行分页（是真好用）

首先引入相关的jar包：

然后是在Mybatis全局配置文件中配置：

    <plugins>
        <plugin interceptor="com.github.pagehelper.PageInterceptor"></plugin>
    </plugins>

就可以使用了。

EmployeeMapper.java中

    public List<Employee> getAllEmp();

EmployeeMapper.xml中

    <select id="getAllEmp" resultType="com.gong.mybatis.bean.Employee">
        select * from tbl_employee
    </select>

进行测试：首先是不带分页的测试

package com.gong.mybatis.test;

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

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 org.junit.Test;

import com.github.pagehelper.Page;
import com.github.pagehelper.PageHelper;
import com.github.pagehelper.PageInfo;
import com.gong.mybatis.bean.Department;
import com.gong.mybatis.bean.Employee;
import com.gong.mybatis.dao.EmployeeMapper;
import com.gong.mybatis.mapper.EmployeeMapperDynamicSql;

public class TestMybatis5 {
    
    public SqlSessionFactory getSqlSessionFactory() throws IOException {
        String resource = "mybatis-config.xml";
        InputStream is = Resources.getResourceAsStream(resource);
        return new SqlSessionFactoryBuilder().build(is);
    }

    @Test
    public void test() throws IOException {
        SqlSessionFactory sqlSessionFactory = getSqlSessionFactory();
        SqlSession openSession = sqlSessionFactory.openSession();
        
        try {
            EmployeeMapper mapper = openSession.getMapper(EmployeeMapper.class);
            List<Employee> emps = mapper.getAllEmp();
            for(Employee emp:emps) {
                System.out.println(emp);
            }

        } finally {
            // TODO: handle finally clause
            openSession.close();
        }
    }
    
}

输出：

DEBUG 01-23 14:29:17,295 ==>  Preparing: select * from tbl_employee   (BaseJdbcLogger.java:145) 
DEBUG 01-23 14:29:17,334 ==> Parameters:   (BaseJdbcLogger.java:145) 
DEBUG 01-23 14:29:17,412 <==      Total: 7  (BaseJdbcLogger.java:145) 
Employee [id=1, lastName=dema, gender=1, email=dema@qq.com, dept=null]
Employee [id=2, lastName=jack, gender=1, email=675544321@qq.com, dept=null]
Employee [id=3, lastName=小红, gender=0, email=xiaohong@qq.com, dept=null]
Employee [id=4, lastName=小明, gender=0, email=xiaoming@qq.com, dept=null]
Employee [id=6, lastName=timo, gender=0, email=timo@qq.com, dept=null]
Employee [id=7, lastName=manwang, gender=1, email=manwang@qq.com, dept=null]
Employee [id=8, lastName=timo, gender=0, email=timo@qq.com, dept=null]

我们共有7条数据。

第一种分页方式：

package com.gong.mybatis.test;

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

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 org.junit.Test;

import com.github.pagehelper.Page;
import com.github.pagehelper.PageHelper;
import com.github.pagehelper.PageInfo;
import com.gong.mybatis.bean.Department;
import com.gong.mybatis.bean.Employee;
import com.gong.mybatis.dao.EmployeeMapper;
import com.gong.mybatis.mapper.EmployeeMapperDynamicSql;

public class TestMybatis5 {
    
    public SqlSessionFactory getSqlSessionFactory() throws IOException {
        String resource = "mybatis-config.xml";
        InputStream is = Resources.getResourceAsStream(resource);
        return new SqlSessionFactoryBuilder().build(is);
    }

    @Test
    public void test() throws IOException {
        SqlSessionFactory sqlSessionFactory = getSqlSessionFactory();
        SqlSession openSession = sqlSessionFactory.openSession();
        
        try {
            EmployeeMapper mapper = openSession.getMapper(EmployeeMapper.class);
            //第一个参数为当前页码，第二个参数是每页的记录数
            Page<Object> page = PageHelper.startPage(1,5);
            List<Employee> emps = mapper.getAllEmp();
            for(Employee emp:emps) {
                System.out.println(emp);
            }
            System.out.println("当前页码："+page.getPageNum());
            System.out.println("总记录数："+page.getTotal());
            System.out.println("每页几条记录："+page.getPageSize());
            System.out.println("总页码数："+page.getPages());
        } finally {
            // TODO: handle finally clause
            openSession.close();
        }
    }
}

输出：

DEBUG 01-23 14:32:50,024 Cache Hit Ratio [SQL_CACHE]: 0.0  (LoggingCache.java:62) 
DEBUG 01-23 14:32:50,071 ==>  Preparing: SELECT count(0) FROM tbl_employee   (BaseJdbcLogger.java:145) 
DEBUG 01-23 14:32:50,128 ==> Parameters:   (BaseJdbcLogger.java:145) 
DEBUG 01-23 14:32:50,197 <==      Total: 1  (BaseJdbcLogger.java:145) 
DEBUG 01-23 14:32:50,199 ==>  Preparing: select * from tbl_employee LIMIT 5   (BaseJdbcLogger.java:145) 
DEBUG 01-23 14:32:50,199 ==> Parameters:   (BaseJdbcLogger.java:145) 
DEBUG 01-23 14:32:50,212 <==      Total: 5  (BaseJdbcLogger.java:145) 
Employee [id=1, lastName=dema, gender=1, email=dema@qq.com, dept=null]
Employee [id=2, lastName=jack, gender=1, email=675544321@qq.com, dept=null]
Employee [id=3, lastName=小红, gender=0, email=xiaohong@qq.com, dept=null]
Employee [id=4, lastName=小明, gender=0, email=xiaoming@qq.com, dept=null]
Employee [id=6, lastName=timo, gender=0, email=timo@qq.com, dept=null]
当前页码：1
总记录数：7
每页几条记录：5
总页码数：2

第二种分页方式：

在上一种设置起始页和每页记录的情况下继续增加：

package com.gong.mybatis.test;

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

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 org.junit.Test;

import com.github.pagehelper.Page;
import com.github.pagehelper.PageHelper;
import com.github.pagehelper.PageInfo;
import com.gong.mybatis.bean.Department;
import com.gong.mybatis.bean.Employee;
import com.gong.mybatis.dao.EmployeeMapper;
import com.gong.mybatis.mapper.EmployeeMapperDynamicSql;

public class TestMybatis5 {
    
    public SqlSessionFactory getSqlSessionFactory() throws IOException {
        String resource = "mybatis-config.xml";
        InputStream is = Resources.getResourceAsStream(resource);
        return new SqlSessionFactoryBuilder().build(is);
    }

    @Test
    public void test() throws IOException {
        SqlSessionFactory sqlSessionFactory = getSqlSessionFactory();
        SqlSession openSession = sqlSessionFactory.openSession();
        
        try {
            EmployeeMapper mapper = openSession.getMapper(EmployeeMapper.class);
            //第一个参数为当前页码，第二个参数是每页的记录数
            Page<Object> page = PageHelper.startPage(1,2);
            List<Employee> emps = mapper.getAllEmp();
            //第一个参数为传入的数据，第二个参数为连续显示多少页
            PageInfo<Employee> pageInfo = new PageInfo<>(emps,3);
            for(Employee emp:emps) {
                System.out.println(emp);
            }
            System.out.println("当前页码："+pageInfo.getPageNum());
            System.out.println("总记录数："+pageInfo.getTotal());
            System.out.println("每页几条记录："+pageInfo.getPageSize());
            System.out.println("总页码数："+pageInfo.getPages());
            System.out.println("是否第一页："+pageInfo.isIsFirstPage());
            System.out.println("是否最后一页："+pageInfo.isIsLastPage());
            System.out.println("连续显示的页码：");
            int[] navigatepageNums = pageInfo.getNavigatepageNums();
            for (int i = 0; i < navigatepageNums.length; i++) {
                System.out.println(navigatepageNums[i]);
            }
        } finally {
            // TODO: handle finally clause
            openSession.close();
        }
    }
    
}

输出：

DEBUG 01-23 14:39:20,125 Cache Hit Ratio [SQL_CACHE]: 0.0  (LoggingCache.java:62) 
DEBUG 01-23 14:39:20,172 ==>  Preparing: SELECT count(0) FROM tbl_employee   (BaseJdbcLogger.java:145) 
DEBUG 01-23 14:39:20,247 ==> Parameters:   (BaseJdbcLogger.java:145) 
DEBUG 01-23 14:39:20,278 <==      Total: 1  (BaseJdbcLogger.java:145) 
DEBUG 01-23 14:39:20,281 ==>  Preparing: select * from tbl_employee LIMIT 2   (BaseJdbcLogger.java:145) 
DEBUG 01-23 14:39:20,283 ==> Parameters:   (BaseJdbcLogger.java:145) 
DEBUG 01-23 14:39:20,292 <==      Total: 2  (BaseJdbcLogger.java:145) 
Employee [id=1, lastName=dema, gender=1, email=dema@qq.com, dept=null]
Employee [id=2, lastName=jack, gender=1, email=675544321@qq.com, dept=null]
当前页码：1
总记录数：7
每页几条记录：2
总页码数：4
是否第一页：true
是否最后一页：false
连续显示的页码：
1
2
3