6.MyBaits的分页和缓存查询

1. 创建javaweb项目MyBaits_Page_CaChe

2.在项目的WebRoot下的WEB-INF下的lib文件下加入jar文件

log4j-1.2.17.jar

mybatis-3.2.3.jar

ojdbc14.jar

3.在src下创建jdbc.properties属性文件

 driver=oracle.jdbc.driver.OracleDriver
 url=jdbc\:oracle\:thin\:@127.0.0.1\:1521\:orcl
 username=scott
 password=tiger

jdbc.properties

4.在src下创建configuration.xml主配置文件

 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd" >
 <configuration>
   <!-- 引用jdbc链接数据库属性文件 -->
   <properties resource="jdbc.properties"/>

   <!-- 全局参数的配置 -->
    <settings>
      <!-- 开启二级缓存 -->
      <setting name="cacheEnabled" value="true"/>
    </settings>

   <!-- 配置别名 -->
   <typeAliases>
     <typeAlias type="com.entity.Emp" alias="Emp"/>
     <typeAlias type="com.page.EmpPage" alias="EmpPage"/>
   </typeAliases>

   <environments default="development">
     <environment id="development">
       <transactionManager type="jdbc"/>
       <dataSource type="POOLED">
         <property name="driver" value="${driver}"/>
         <property name="url" value="${url}"/>
         <property name="username" value="${username}"/>
         <property name="password" value="${password}"/>
       </dataSource>

     </environment>

   </environments>

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

 </configuration>

configuration.xml

5.在src下创建log4j.properties日志文件

 log4j.rootLogger=DEBUG,Console 

 #Console
 log4j.appender.Console=org.apache.log4j.ConsoleAppender
 log4j.appender.stdout.Target=System.err
 log4j.appender.Console.layout=org.apache.log4j.PatternLayout 

 ###log4j to file###
 log4j.appender.logfile=org.apache.log4j.FileAppender
 log4j.appender.logfile.File=mybatis.log
 log4j.appender.logfile.layout=org.apache.log4j.PatternLayout
 log4j.appender.Console.layout.ConversionPattern=%d %p %F %M [%t] %-5p [%c] - %m%n  

 log4j.logger.java.sql.ResultSet=INFO
 log4j.logger.org.apache=INFO
 log4j.logger.java.sql.Connection=DEBUG
 log4j.logger.java.sql.Statement=DEBUG
 log4j.logger.java.sql.PreparedStatement=DEBUG   

6.在src下创建com.entity包下创建Emp.java

 package com.entity;

 public class Emp {
     private int empno;
     private String ename;
     private double sal;
     private int deptno;

     public Emp() {
     }
     public Emp(int empno, String ename, double sal, int deptno) {
         this.empno = empno;
         this.ename = ename;
         this.sal = sal;
         this.deptno = deptno;
     }
     public int getEmpno() {
         return empno;
     }
     public void setEmpno(int empno) {
         this.empno = empno;
     }
     public String getEname() {
         return ename;
     }
     public void setEname(String ename) {
         this.ename = ename;
     }
     public double getSal() {
         return sal;
     }
     public void setSal(double sal) {
         this.sal = sal;
     }
     public int getDeptno() {
         return deptno;
     }
     public void setDeptno(int deptno) {
         this.deptno = deptno;
     }
     @Override
     public String toString() {
         return "Emp [deptno=" + deptno + ", empno=" + empno + ", ename="
                 + ename + ", sal=" + sal + "]";
     }

 }

Emp.java

7.在src下创建com.util包下创建MyBatisUtil.java

 package com.util;

 import java.io.IOException;
 import java.io.Reader;

 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 MyBatisUtil {
     private static SqlSessionFactory sqlSessionFactory=null;
     static{
         try {
             Reader reader=Resources.getResourceAsReader("configuration.xml");
             sqlSessionFactory=new SqlSessionFactoryBuilder().build(reader);
         } catch (IOException e) {
             e.printStackTrace();
         }

     }

     public static SqlSession getSqlSession(boolean isCommit){
         return sqlSessionFactory.openSession(isCommit);
     }

 }

MyBatisUtil.java

8.在src下创建com.page包下创建EmpPage.java

 package com.page;

 import java.util.List;

 import org.apache.ibatis.session.SqlSession;

 import com.entity.Emp;
 import com.mapper.EmpMapper;
 import com.util.MyBatisUtil;

 public class EmpPage {
     private Integer pageNo;
     private Integer pageSize;
     private Integer totalPage;
     private Integer totalCount;

     public EmpPage() {
     }
     public EmpPage(Integer pageNo, Integer pageSize) {
         this.pageNo = pageNo;
         this.pageSize = pageSize;
     }
     public Integer getPageNo() {
         return pageNo;
     }
     public void setPageNo(Integer pageNo) {
         if(pageNo!=null){
             this.pageNo = pageNo;
         }else{
             this.pageNo=1;
         }

     }
     public Integer getPageSize() {
         return pageSize;
     }
     public void setPageSize(Integer pageSize) {
         this.pageSize = pageSize;
     }
     public Integer getTotalPage() {
         return totalPage;
     }
     public void setTotalPage(Integer totalPage) {
         this.totalPage = totalPage;
     }
     public Integer getTotalCount() {
         return totalCount;
     }
     public void setTotalCount(Integer totalCount) {
         this.totalCount = totalCount;
     }

     /**
      * 查询总记录数
      * @return  总记录数
      */
     public int totalCount(){
         SqlSession sqlSession=MyBatisUtil.getSqlSession(false);
         EmpMapper mapper=sqlSession.getMapper(EmpMapper.class);
         Integer count=mapper.totalCount();
         sqlSession.clearCache();
         sqlSession.close();

         //修改

         return count;
     }

     /**
      * 计算总页数
      * @param pageSize 页面大小
      * @param totalCount 总的记录数
      * @return 总页数
      */
     public int totalPage(int pageSize,int totalCount){
         int count=totalCount%pageSize==0?totalCount/pageSize:totalCount/pageSize+1;
         this.setTotalPage(count);
         return count;
     }

     /**
      * 分页查询
      * @param pageSize  页面大小
      * @param pageNo  当前页
      * @return 分页查询集合
      */
     public List<Emp> findEmpPage(EmpPage page){
         SqlSession sqlSession=MyBatisUtil.getSqlSession(false);
         EmpMapper mapper=sqlSession.getMapper(EmpMapper.class);
         List<Emp> list=mapper.findEmpPage(page);
         sqlSession.close();
         return list;
     }

 }

EmpPage.java

9.在src下创建com.mapper包下创建EmpMapper.java

 package com.mapper;

 import java.util.List;

 import com.entity.Emp;
 import com.page.EmpPage;

 public interface EmpMapper {
     /**
      * 查询总条数
      * @return
      */
     Integer totalCount();

     /**
      * 分页查询
      */
     List<Emp> findEmpPage(EmpPage page);

 }

EmpMapper.java

10.在src下创建com.test包下创建EmpMapper.xml

 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
 <mapper namespace="com.mapper.EmpMapper">
 <!-- 开启二级缓存 -->
   <!--回收策略为先进先出-->
   <!--自动刷新时间60s-->
   <!--最多缓存512个引用对象-->
   <!--只读-->
  <cache eviction="FIFO" flushInterval="60000" size="512" readOnly="true"/> 

   <!-- 查询总条数 -->
   <select id="totalCount" resultType="Integer">
     select count(*) from emp
   </select>

   <!-- 分页查询 -->
   <select id="findEmpPage" resultType="Emp" parameterType="EmpPage">
    <![CDATA[
       select e.empno,e.ename,e.sal,e.deptno from
       (
          select rownum r,empno,ename,sal,deptno from emp
          where rownum<=(#{pageNo}*#{pageSize})
       )e where
         e.r>(#{pageNo}-1)*#{pageSize}
    ]]>

    <!--
     select e.empno,e.ename,e.sal,e.deptno from
       (
          select rownum r,empno,ename,sal,deptno from emp
          where rownum<=3
       )e where
         e.r>0
         -->

   </select>

 </mapper>

EmpMapper.xml

11.在src下创建com.mapper包下创建Test.java

 package com.test;

 import java.util.List;

 import com.entity.Emp;
 import com.page.EmpPage;

 public class Test {

     public static void main(String[] args) {
         EmpPage page=new EmpPage(2, 3);
         int count=page.totalCount();
         count=page.totalCount();
         System.out.println("------总条数："+count);
         System.out.println("-----------分页查询数据如下---------");
         List<Emp> list=page.findEmpPage(page);
         for (Emp emp : list) {
             System.out.println(emp);
         }
     }

 }

Test.java