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

1 driver=oracle.jdbc.driver.OracleDriver
2 url=jdbc:oracle:thin:@127.0.0.1:1521:orcl
3 username=scott
4 password=tiger

jdbc.properties

4.在src下创建configuration.xml主配置文件

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd" >
 3 <configuration>
 4   <!-- 引用jdbc链接数据库属性文件 -->
 5   <properties resource="jdbc.properties"/>
 6   
 7   <!-- 全局参数的配置 -->
 8    <settings>
 9      <!-- 开启二级缓存 -->
10      <setting name="cacheEnabled" value="true"/>
11    </settings>
12    
13    
14   <!-- 配置别名 -->
15   <typeAliases>
16     <typeAlias type="com.entity.Emp" alias="Emp"/>
17     <typeAlias type="com.page.EmpPage" alias="EmpPage"/>
18   </typeAliases>
19 
20   <environments default="development">
21     <environment id="development">
22       <transactionManager type="jdbc"/>
23       <dataSource type="POOLED">
24         <property name="driver" value="${driver}"/>
25         <property name="url" value="${url}"/>
26         <property name="username" value="${username}"/>
27         <property name="password" value="${password}"/>
28       </dataSource>
29       
30       
31       
32     </environment>
33     
34     
35   </environments>
36   
37   <mappers>
38     <mapper resource="com/mapper/EmpMapper.xml"/>
39   </mappers>
40   
41 </configuration>

configuration.xml

5.在src下创建log4j.properties日志文件

 1 log4j.rootLogger=DEBUG,Console 
 2   
 3 #Console  
 4 log4j.appender.Console=org.apache.log4j.ConsoleAppender
 5 log4j.appender.stdout.Target=System.err  
 6 log4j.appender.Console.layout=org.apache.log4j.PatternLayout 
 7 
 8 ###log4j to file###
 9 log4j.appender.logfile=org.apache.log4j.FileAppender
10 log4j.appender.logfile.File=mybatis.log
11 log4j.appender.logfile.layout=org.apache.log4j.PatternLayout 
12 log4j.appender.Console.layout.ConversionPattern=%d %p %F %M [%t] %-5p [%c] - %m%n  
13   
14 log4j.logger.java.sql.ResultSet=INFO  
15 log4j.logger.org.apache=INFO  
16 log4j.logger.java.sql.Connection=DEBUG  
17 log4j.logger.java.sql.Statement=DEBUG  
18 log4j.logger.java.sql.PreparedStatement=DEBUG

6.在src下创建com.entity包下创建Emp.java

 1 package com.entity;
 2 
 3 public class Emp {
 4     private int empno;
 5     private String ename;
 6     private double sal;
 7     private int deptno;
 8     
 9     public Emp() {
10     }
11     public Emp(int empno, String ename, double sal, int deptno) {
12         this.empno = empno;
13         this.ename = ename;
14         this.sal = sal;
15         this.deptno = deptno;
16     }
17     public int getEmpno() {
18         return empno;
19     }
20     public void setEmpno(int empno) {
21         this.empno = empno;
22     }
23     public String getEname() {
24         return ename;
25     }
26     public void setEname(String ename) {
27         this.ename = ename;
28     }
29     public double getSal() {
30         return sal;
31     }
32     public void setSal(double sal) {
33         this.sal = sal;
34     }
35     public int getDeptno() {
36         return deptno;
37     }
38     public void setDeptno(int deptno) {
39         this.deptno = deptno;
40     }
41     @Override
42     public String toString() {
43         return "Emp [deptno=" + deptno + ", empno=" + empno + ", ename="
44                 + ename + ", sal=" + sal + "]";
45     }
46     
47 
48 }

Emp.java

7.在src下创建com.util包下创建MyBatisUtil.java

 1 package com.util;
 2 
 3 import java.io.IOException;
 4 import java.io.Reader;
 5 
 6 import org.apache.ibatis.io.Resources;
 7 import org.apache.ibatis.session.SqlSession;
 8 import org.apache.ibatis.session.SqlSessionFactory;
 9 import org.apache.ibatis.session.SqlSessionFactoryBuilder;
10 
11 public class MyBatisUtil {
12     private static SqlSessionFactory sqlSessionFactory=null;
13     static{
14         try {
15             Reader reader=Resources.getResourceAsReader("configuration.xml");
16             sqlSessionFactory=new SqlSessionFactoryBuilder().build(reader);
17         } catch (IOException e) {
18             e.printStackTrace();
19         }
20         
21     }
22     
23     public static SqlSession getSqlSession(boolean isCommit){
24         return sqlSessionFactory.openSession(isCommit);
25     }
26 
27 }

MyBatisUtil.java

8.在src下创建com.page包下创建EmpPage.java

 1 package com.page;
 2 
 3 import java.util.List;
 4 
 5 import org.apache.ibatis.session.SqlSession;
 6 
 7 import com.entity.Emp;
 8 import com.mapper.EmpMapper;
 9 import com.util.MyBatisUtil;
10 
11 public class EmpPage {
12     private Integer pageNo;
13     private Integer pageSize;
14     private Integer totalPage;
15     private Integer totalCount;
16     
17     
18     public EmpPage() {
19     }
20     public EmpPage(Integer pageNo, Integer pageSize) {
21         this.pageNo = pageNo;
22         this.pageSize = pageSize;
23     }
24     public Integer getPageNo() {
25         return pageNo;
26     }
27     public void setPageNo(Integer pageNo) {
28         if(pageNo!=null){
29             this.pageNo = pageNo;
30         }else{
31             this.pageNo=1;
32         }
33         
34     }
35     public Integer getPageSize() {
36         return pageSize;
37     }
38     public void setPageSize(Integer pageSize) {
39         this.pageSize = pageSize;
40     }
41     public Integer getTotalPage() {
42         return totalPage;
43     }
44     public void setTotalPage(Integer totalPage) {
45         this.totalPage = totalPage;
46     }
47     public Integer getTotalCount() {
48         return totalCount;
49     }
50     public void setTotalCount(Integer totalCount) {
51         this.totalCount = totalCount;
52     }
53     
54     /**
55      * 查询总记录数
56      * @return  总记录数
57      */
58     public int totalCount(){
59         SqlSession sqlSession=MyBatisUtil.getSqlSession(false);
60         EmpMapper mapper=sqlSession.getMapper(EmpMapper.class);
61         Integer count=mapper.totalCount();
62         sqlSession.clearCache();
63         sqlSession.close();
64          
65         //修改
66         
67         return count;
68     }
69     
70     /**
71      * 计算总页数
72      * @param pageSize 页面大小
73      * @param totalCount 总的记录数
74      * @return 总页数
75      */
76     public int totalPage(int pageSize,int totalCount){
77         int count=totalCount%pageSize==0?totalCount/pageSize:totalCount/pageSize+1;
78         this.setTotalPage(count);
79         return count;
80     }
81     
82     /**
83      * 分页查询
84      * @param pageSize  页面大小
85      * @param pageNo  当前页
86      * @return 分页查询集合
87      */
88     public List<Emp> findEmpPage(EmpPage page){
89         SqlSession sqlSession=MyBatisUtil.getSqlSession(false);
90         EmpMapper mapper=sqlSession.getMapper(EmpMapper.class);
91         List<Emp> list=mapper.findEmpPage(page);
92         sqlSession.close();
93         return list;
94     }
95     
96 
97 }

EmpPage.java

9.在src下创建com.mapper包下创建EmpMapper.java

 1 package com.mapper;
 2 
 3 import java.util.List;
 4 
 5 import com.entity.Emp;
 6 import com.page.EmpPage;
 7 
 8 public interface EmpMapper {
 9     /**
10      * 查询总条数
11      * @return
12      */
13     Integer totalCount();
14 
15     /**
16      * 分页查询
17      */
18     List<Emp> findEmpPage(EmpPage page);
19 
20 }

EmpMapper.java

10.在src下创建com.test包下创建EmpMapper.xml

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
 3 <mapper namespace="com.mapper.EmpMapper">
 4 <!-- 开启二级缓存 -->
 5   <!--回收策略为先进先出-->
 6   <!--自动刷新时间60s-->
 7   <!--最多缓存512个引用对象-->
 8   <!--只读-->
 9  <cache eviction="FIFO" flushInterval="60000" size="512" readOnly="true"/> 
10     
11   <!-- 查询总条数 --> 
12   <select id="totalCount" resultType="Integer">
13     select count(*) from emp
14   </select>
15   
16   <!-- 分页查询 -->
17   <select id="findEmpPage" resultType="Emp" parameterType="EmpPage">
18    <![CDATA[
19       select e.empno,e.ename,e.sal,e.deptno from 
20       (
21          select rownum r,empno,ename,sal,deptno from emp
22          where rownum<=(#{pageNo}*#{pageSize})
23       )e where
24         e.r>(#{pageNo}-1)*#{pageSize}
25    ]]>
26    
27    <!--  
28     select e.empno,e.ename,e.sal,e.deptno from 
29       (
30          select rownum r,empno,ename,sal,deptno from emp
31          where rownum<=3 
32       )e where
33         e.r>0 
34         -->
35   
36   </select>
37   
38 </mapper>

EmpMapper.xml

11.在src下创建com.mapper包下创建Test.java

 1 package com.test;
 2 
 3 import java.util.List;
 4 
 5 import com.entity.Emp;
 6 import com.page.EmpPage;
 7 
 8 public class Test {
 9 
10     public static void main(String[] args) {
11         EmpPage page=new EmpPage(2, 3);
12         int count=page.totalCount();
13         count=page.totalCount();
14         System.out.println("------总条数："+count);
15         System.out.println("-----------分页查询数据如下---------");
16         List<Emp> list=page.findEmpPage(page);
17         for (Emp emp : list) {
18             System.out.println(emp);
19         }
20     }
21 
22 }

Test.java

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原文地址：https://www.cnblogs.com/holly8/p/5801376.html