使用mysql实现mybatis的分页效果

1、mybatis.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"./mybatis-3-config.dtd">
<configuration>
<!-- properties配置文件中属性值，在整个配置文件中通过${}进行引用 -->
<properties>
	<property name="driver" value="com.mysql.jdbc.Driver" />
</properties>  
 
<typeAliases>
  <typeAlias type="com.wh.pojo.Emp" alias="Emp"/>
</typeAliases> 
  
<!-- 数据源环境信息配置 -->  
<environments default="development2">

	<environment id="development">
		<transactionManager type="JDBC" />
		<dataSource type="POOLED">
			<!-- mysql数据源配置 -->
			<property name="driver" value="${driver}" />
			<property name="url" value="jdbc:mysql://localhost/ys" />
			<property name="username" value="root" />
			<property name="password" value="admin" />
		</dataSource>
	</environment>
	
	<environment id="development2">
		<transactionManager type="JDBC" />
		<dataSource type="POOLED">
			<!-- oracle数据源配置 -->
			<property name="driver" value="oracle.jdbc.driver.OracleDriver" />
			<property name="url" value="jdbc:oracle:thin:@127.0.0.1:1521:orcl" />
			<property name="username" value="scott" />
			<property name="password" value="tiger" />
		</dataSource>
	</environment>
</environments>

<mappers>
	<mapper resource="com/wh/mapper/DeptMapper.xml" />
	<mapper resource="com/wh/mapper/EmpMapper.xml" />
</mappers>

</configuration>

2、DeptMapper.java

package com.wh.mapper;

import java.util.List;

import org.apache.ibatis.annotations.Param;

import com.wh.pojo.Dept;
import com.wh.vo.VO;

public interface DeptMapper {

	public List<Dept> selectByName(String name);
	
	public List<Dept> selectByMore(@Param("dpt_name")String dpt_name,@Param("dpt_ioc")String dpt_ioc);

	public List<Dept> selectByList(@Param("ids") List<Integer> ids);
	
	public List<Dept> selectPage(VO vo);
}

3、DeptMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
	"./mybatis-3-mapper.dtd">
	
<!--namespace 绑定接口   -->	
<mapper namespace="com.wh.mapper.DeptMapper"> 
	<!-- DeptResultMap  -->
	<resultMap id="DeptResultMap" type="com.wh.pojo.Dept2">
		<id property="did" column="dpt_id" />
		<result property="dname" column="dpt_name" />
		<result property="dioc" column="dpt_ioc" />
	</resultMap>

	<!-- 模糊查询  -->
	<select id="selectByName" parameterType="java.lang.String" resultType="com.wh.pojo.Dept"> 
		<!-- select * from dept where dpt_name like concat('%',#{dpt_name},'%') -->
		select * from dept where dpt_name like '%${value}%'
	</select>
	
	<!-- 多重条件查询   接口要对形参注解          concat('%','销售','%')   -->
	<select id="selectByMore" resultType="com.wh.pojo.Dept"> 
		select * from dept where 1=1 
		<if test="dpt_name!=null and dpt_name!='' ">
			and dpt_name like concat('%',#{dpt_name,jdbcType=VARCHAR},'%')
		</if>
		<if test="dpt_ioc!=null and dpt_ioc!='' ">
			and dpt_ioc like concat(concat('%',#{dpt_ioc,jdbcType=VARCHAR}),'%')
		</if>
	</select>
	
	<!-- 集合查询   in -->
	<select id="selectByList" resultType="com.wh.pojo.Dept"> 
		select * from dept where dpt_id in
		<foreach collection="ids" index="index" open="(" separator="," close=")" item="id">
			#{id}
		</foreach>
	</select>
	
	<!-- 分页查询  -->
	<select id="selectPage" resultType="com.wh.pojo.Dept" parameterType="com.wh.vo.VO"> 
		select * from dept limit #{pager.start},#{pager.pageSize}
	</select>	
</mapper>

4、DeptDaoImpl.java　　

package com.wh.mapperImpl;

import java.util.List;

import com.wh.mapper.DeptMapper;
import com.wh.pojo.Dept;
import com.wh.vo.VO;


public class DeptDaoImpl extends BaseDao implements DeptMapper {

	@Override
	public List<Dept> selectByName(String name) {
		this.openSession();
		DeptMapper mapper=(DeptMapper) ss.getMapper(DeptMapper.class);
		return mapper.selectByName(name);
	}

	@Override
	public List<Dept> selectByMore(String dpt_name, String dpt_ioc) {
		this.openSession();
		DeptMapper mapper=(DeptMapper) ss.getMapper(DeptMapper.class);
		return mapper.selectByMore(dpt_name,dpt_ioc);
	}

	@Override
	public List<Dept> selectByList(List<Integer> ids) {
		this.openSession();
		DeptMapper mapper=(DeptMapper) ss.getMapper(DeptMapper.class);
		return mapper.selectByList(ids);
	}

	@Override
	public List<Dept> selectPage(VO vo) {
		this.openSession();
		DeptMapper mapper=(DeptMapper) ss.getMapper(DeptMapper.class);
		return mapper.selectPage(vo); 
	}

}

5、Pager.java

package com.wh.common;

public class Pager {
	private int recordCount ;//总记录数
	private int pageSize = 3;//每页个数 自定义
	private int pageCount ; //总页数
	private int pageNum;//当前页数
	private int start;//起始记录数
	public Pager(int recordCount, int pageNum) {
		super();
		this.recordCount = recordCount;
		this.pageNum = pageNum;
		//总页数
		if(recordCount % pageSize == 0){
			pageCount = recordCount / pageSize;
		}else{
			pageCount = recordCount / pageSize + 1;
		}
		//当前页码处理
		if(pageNum < 1){
			pageNum = 1;
		}
		if(pageNum > pageCount){
			pageNum = pageCount;
		}
		//起始位置       mysql起始位置要减去1
		start = (pageNum - 1) * pageSize;
		
	}
	public int getRecordCount() {
		return recordCount;
	}
	public void setRecordCount(int recordCount) {
		this.recordCount = recordCount;
	}
	public int getPageSize() {
		return pageSize;
	}
	public void setPageSize(int pageSize) {
		this.pageSize = pageSize;
	}
	public int getPageCount() {
		return pageCount;
	}
	public void setPageCount(int pageCount) {
		this.pageCount = pageCount;
	}
	public int getPageNum() {
		return pageNum;
	}
	public void setPageNum(int pageNum) {
		this.pageNum = pageNum;
	}
	public int getStart() {
		return start;
	}
	public void setStart(int start) {
		this.start = start;
	}	
}

6、Vo.java

package com.wh.vo;

import com.wh.common.Pager;

public class VO {

	private Pager pager;

	public VO(Pager pager) {
		super();
		this.pager = pager;
	}

	public Pager getPager() {
		return pager;
	}

	public void setPager(Pager pager) {
		this.pager = pager;
	}

}

TestDept.java

package com.wh.junit;
/**
 * mybatis编写顺序
 * DeptMapper.java、DeptMapper.xml、DeptDaoImpl.java、TestMyBatis.java
 */
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
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 org.junit.Test;

import com.wh.common.Pager;
import com.wh.mapperImpl.DeptDaoImpl;
import com.wh.pojo.Dept;
import com.wh.vo.VO;

public class TestDept {

	//mybatis快速入门
	@Test
	public void test00() throws IOException{
		InputStream in = Resources.getResourceAsStream("mybatis.xml");
		SqlSessionFactory ssf=new SqlSessionFactoryBuilder().build(in);
		SqlSession ss=ssf.openSession();
		String string = ss.toString();
		System.out.println(string); 
	}
	
	//mybatis快速入门    二
	@Test
	public void test01() throws IOException{
		InputStream in = Resources.getResourceAsStream("mybatis.xml");
		SqlSessionFactory ssf=new SqlSessionFactoryBuilder().build(in);
		SqlSession ss=ssf.openSession();
		
//		String string = "com.wh.mapper.DeptMapper.selectById";
//		Object selectOne = ss.selectOne(string,5); 
//		System.out.println(selectOne); 
		String string = "com.wh.mapper.DeptMapper.sAll";
		Object select = ss.selectList(string); 
		System.out.println(select); 
	}
	
	//模糊查询
	@Test
	public void testselectByName() throws IOException{
		DeptDaoImpl dao=new DeptDaoImpl(); 
		List<Dept> list = dao.selectByName("销");
		System.out.println(list);
 	}
	
	//多重条件查询
	@Test
	public void testSelectByMore() throws IOException{
		DeptDaoImpl dao=new DeptDaoImpl(); 
		List<Dept> list = dao.selectByMore("销","2");
		System.out.println(list);
	}
	
	//集合查询   in
	@Test
	public void testSelectByList() throws IOException{
		DeptDaoImpl dao=new DeptDaoImpl(); 
		List<Integer> ids=new ArrayList<Integer>();
		ids.add(1);
		ids.add(3);
		List<Dept> list = dao.selectByList(ids);
		System.out.println(list);
	}
	
	//分页查询
	@Test
	public void testSelectPage() throws IOException{
		DeptDaoImpl dao=new DeptDaoImpl(); 
		List<Dept> list = dao.selectPage(new VO(new Pager(5,1)));
		System.out.println(list);
 	}
}

BaseDao

package com.wh.mapperImpl;
/**
 * 将mybatis中事务管理这一块，用单例模式实现
 */
import java.io.IOException;
import java.io.InputStream;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

public class BaseDao {

	private static SqlSessionFactory ssf;
	public SqlSession ss;

	static {
		String resource = "mybatis.xml";
		try {
			// 读取配置文件
			InputStream in = Resources.getResourceAsStream(resource);
			// 创建连接工厂
			ssf = new SqlSessionFactoryBuilder().build(in);
		}
		catch (IOException e) {
			e.printStackTrace();
		}
	}

	// 获得连接
	public SqlSession openSession() {
		if (ss == null) {
			// 事务自动提交，默认是false不自动提交   true自动提交
			ss = ssf.openSession(true);
		}
		return ss;
	}

	// 提交
	public void commit() {
		if (ss != null) {
			ss.commit();
		}
	}

	// 回滚
	public void rollback() {
		if (ss != null) {
			ss.rollback();
		}
	}

	// 关闭连接
	public void close() {
		if (ss != null) {
			ss.close();
		}
	}
}