MyBatis入门（五）---延时加载、缓存

一、创建数据库

1.1、建立数据库

 

/*SQLyog EnterPRise v12.09 (64 bit)MySQL - 5.7.9-log : Database - mybatis
**********************************************************************//*!40101 SET NAMES utf8 */;/*!40101 SET SQL_MODE=''*/;/*!40014 SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0 */;/*!40014 SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 */;/*!40101 SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='NO_AUTO_VALUE_ON_ZERO' */;/*!40111 SET @OLD_SQL_NOTES=@@SQL_NOTES, SQL_NOTES=0 */;CREATE DATABASE /*!32312 IF NOT EXISTS*/`mybatis` /*!40100 DEFAULT CHARACTER SET utf8 */;USE `mybatis`;/*Table structure for table `author` */DROP TABLE IF EXISTS `author`;CREATE TABLE `author` (
 `author_id` int(11) unsigned NOT NULL AUTO_INCREMENT COMMENT '作者ID主键',
 `author_username` varchar(30) NOT NULL COMMENT '作者用户名',
 `author_passWord` varchar(32) NOT NULL COMMENT '作者密码',
 `author_email` varchar(50) NOT NULL COMMENT '作者邮箱',
 `author_bio` varchar(1000) DEFAULT '这家伙很赖，什么也没留下' COMMENT '作者简介',
 `register_time` datetime DEFAULT CURRENT_TIMESTAMP COMMENT '注册时间',  PRIMARY KEY (`author_id`)
) ENGINE=InnoDB AUTO_INCREMENT=11 DEFAULT CHARSET=utf8;/*Data for the table `author` */insert  into `author`(`author_id`,`author_username`,`author_password`,`author_email`,`author_bio`,`register_time`) values (1,'张三','123456','123@QQ.com','张三是个新手，刚开始注册','2015-10-29 10:23:59'),(2,'李四','123asf','lisi@163.com','魂牵梦萦 ','2015-10-29 10:24:29'),(3,'王五','dfsd342','ww@sina.com','康熙王朝','2015-10-29 10:25:23'),(4,'赵六','123098sdfa','zhaoliu@qq.com','花午骨','2015-10-29 10:26:09'),(5,'钱七','zxasqw','qianqi@qq.com','这家伙很赖，什么也没留下','2015-10-29 10:27:04'),(6,'张三丰','123456','zhangsf@qq.com','这家伙很赖，什么也没留下','2015-10-29 11:48:00'),(7,'张无忌','qwertyuiop','wuji@163.com','这家伙很赖，什么也没留下','2015-10-29 11:48:24'),(8,'fdsf','ffff','fdsfds',NULL,NULL),(9,'fdsf','ffff','fdsfds',NULL,NULL),(10,'aaaa','bbbb','ddd@qq.com','这家伙很赖，什么也没留下','2015-10-29 22:07:45');/*Table structure for table `blog` */DROP TABLE IF EXISTS `blog`;CREATE TABLE `blog` (
 `blog_id` int(11) unsigned NOT NULL AUTO_INCREMENT COMMENT 'BlogId主键',
 `blog_title` varchar(255) NOT NULL COMMENT 'blog标题',
 `author_id` int(11) unsigned NOT NULL COMMENT '作者ID外键',  PRIMARY KEY (`blog_id`),  KEY `fk_author_id` (`author_id`),  CONSTRAINT `fk_author_id` FOREIGN KEY (`author_id`) REFERENCES `author` (`author_id`)
) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8;/*Data for the table `blog` */insert  into `blog`(`blog_id`,`blog_title`,`author_id`) values (1,'小张的Blog',1),(2,'小李',2),(3,'王五不是人',3),(4,'赵地人',4),(5,'钱钱钱',5);/*Table structure for table `posts` */DROP TABLE IF EXISTS `posts`;CREATE TABLE `posts` (
 `post_id` int(11) unsigned NOT NULL AUTO_INCREMENT COMMENT '文章主键ID',
 `post_subject` varchar(255) NOT NULL COMMENT '文章主题，标题',
 `post_body` text NOT NULL COMMENT '文章内容最大3000个字符',
 `blog_id` int(11) unsigned NOT NULL COMMENT 'Blog主键做外键',
 `createtime` datetime DEFAULT CURRENT_TIMESTAMP COMMENT '文章创建时间',  PRIMARY KEY (`post_id`),  KEY `fk_blog_id` (`blog_id`),  CONSTRAINT `fk_blog_id` FOREIGN KEY (`blog_id`) REFERENCES `blog` (`blog_id`)
) ENGINE=InnoDB AUTO_INCREMENT=8 DEFAULT CHARSET=utf8mb4;/*Data for the table `posts` */insert  into `posts`(`post_id`,`post_subject`,`post_body`,`blog_id`,`createtime`) values (1,'Mybatis入门一','什么是 MyBatis ？\r\nMyBatis 是支持定制化 SQL、存储过程以及高级映射的优秀的持久层框架。MyBatis 避免了几乎所有的 JDBC 代码和手动设置参数以及获取结果集。MyBatis 可以对配置和原生Map使用简单的 xml 或注解，将接口和 java 的 POJOs(Plain Old Java Objects,普通的 Java对象)映射成数据库中的记录。',1,'2015-10-29 10:32:21'),(2,'Mybatis入门二','要使用 MyBatis， 只需将 mybatis-x.x.x.jar 文件置于 classpath 中即可。',1,'2015-10-29 10:32:52'),(3,'Oracle学习','Oracle Database，又名Oracle RDBMS，或简称Oracle。是甲骨文公司的一款关系数据库管理系统',2,'2015-10-29 10:33:26'),(4,'JAVA学习一','Java是由Sun Microsystems公司于1995年5月推出的Java面向对象程序设计语言和Java平台的总称',3,'2015-10-29 10:34:17'),(5,'PL/SQL','PL/SQL也是一种程序语言，叫做过程化SQL语言（Procedural Language/SQL）。PL/SQL是Oracle数据库对SQL语句的扩展',4,'2015-10-29 10:37:52'),(6,'CSS标签选择器','标签选择器\r\nID选择器\r\n类选择器\r\n特殊选择器',5,'2015-10-29 10:39:44'),(7,'javascript','js:是前端脚本语言',2,'2015-10-29 10:40:18');/*!40101 SET SQL_MODE=@OLD_SQL_MODE */;/*!40014 SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS */;/*!40014 SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS */;/*!40111 SET SQL_NOTES=@OLD_SQL_NOTES */;

数据表和数据

 

 

 

二、创建项目

2.1、创建项目

 

三、建立实体类与Mapper接口

3.1、3个实体类

 

package com.pb.mybatis.po;import java.util.Date;/**
*

* @ClassName: Author

* @Description: TODO(作者)

* @author 刘楠

* @date 2015-10-31 下午12:39:33

* */public class Author {    //作者id
   private Integer authorId;    //作者姓名
   private String authorUserName;    //作者密码
   private String authorPassword;    //作者邮箱
   private String authorEmail;    //作者介绍
   private String authroBio;    //注册时间
   private Date registerTime;    
   
   
   public Integer getAuthorId() {        return authorId;
   }    public void setAuthorId(Integer authorId) {        this.authorId = authorId;
   }    public String getAuthorUserName() {        return authorUserName;
   }    public void setAuthorUserName(String authorUserName) {        this.authorUserName = authorUserName;
   }    public String getAuthorPassword() {        return authorPassword;
   }    public void setAuthorPassword(String authorPassword) {        this.authorPassword = authorPassword;
   }    public String getAuthorEmail() {        return authorEmail;
   }    public void setAuthorEmail(String authorEmail) {        this.authorEmail = authorEmail;
   }    public String getAuthroBio() {        return authroBio;
   }    public void setAuthroBio(String authroBio) {        this.authroBio = authroBio;
   }    public Date getRegisterTime() {        return registerTime;
   }    public void setRegisterTime(Date registerTime) {        this.registerTime = registerTime;
   }
   @Override    public String toString() {        return "Author [authorId=" + authorId + ", authorUserName="
               + authorUserName + ", authorPassword=" + authorPassword                + ", authorEmail=" + authorEmail + ", authroBio=" + authroBio                + ", registerTime=" + registerTime + "]";
   }
   
   
}

 

 

package com.pb.mybatis.po;import java.util.List;public class Blog {    
   //Blog,ID
   private Integer blogId;    //Blog 名称标题
   private String blogTitle;    //外键authorId    //作者
   private Author author;    //文章 列表
   private Integer authorId;    
   //文章列表
   private List postsList;    
   
   public Integer getBlogId() {        return blogId;
   }    public void setBlogId(Integer blogId) {        this.blogId = blogId;
   }    public String getBlogTitle() {        return blogTitle;
   }    public void setBlogTitle(String blogTitle) {        this.blogTitle = blogTitle;
   }    public Author getAuthor() {        return author;
   }    public void setAuthor(Author author) {        this.author = author;
   }    public Integer getAuthorId() {        return authorId;
   }    public void setAuthorId(Integer authorId) {        this.authorId = authorId;
   }    public List getPostsList() {        return postsList;
   }    public void setPostsList(List postsList) {        this.postsList = postsList;
   }
   
   
   @Override    public String toString() {        return "Blog [blogId=" + blogId + ", blogTitle=" + blogTitle                +  ", authorId=" + authorId + "]";
   }
   
   

   
   
   

}

 

package com.pb.mybatis.po;import java.util.Date;public class Posts {    //文章ID
   private Integer postId;    //文章标题
   private String postTitle;    //文章主体内容
   private String postBody;    
   //外键
   private Integer blogId;    //建立时间
   private Date createTime;    
   
   public Integer getPostId() {        return postId;
   }    public void setPostId(Integer postId) {        this.postId = postId;
   }    public String getPostTitle() {        return postTitle;
   }    public void setPostTitle(String postTitle) {        this.postTitle = postTitle;
   }    public String getPostBody() {        return postBody;
   }    public void setPostBody(String postBody) {        this.postBody = postBody;
   }    public Date getCreateTime() {        return createTime;
   }    public void setCreateTime(Date createTime) {        this.createTime = createTime;
   }    
   
   public Integer getBlogId() {        return blogId;
   }    public void setBlogId(Integer blogId) {        this.blogId = blogId;
   }
   @Override    public String toString() {        return "Posts [postId=" + postId + ", postTitle=" + postTitle                + ", postBody=" + postBody + ", createTime=" + createTime                + ", blogId=" + blogId + "]";
   }
   
   
   
   
   
   
}

 

 

 

3.2、3个接口

 

package com.pb.mybatis.mapper;import com.pb.mybatis.po.Author;public interface AuthorMapper {    /**
    *
   
   * @Title: findAuthorById
   
   * @Description: TODO(根据id查找)
   
   * @param @param id
   * @param @return    设定文件
   
   * @return Author    返回类型
   
   * @throws
    */
   public Author findAuthorById(int id);
}

 

package com.pb.mybatis.mapper;import com.pb.mybatis.po.Blog;public interface BlogMapper {    
   /**
    *
   
   * @Title: findBlogById
   
   * @Description: TODO(根据BLOGID查找BLOG，并关联author，与posts实现延时加载)
   
   * @param @param id
   * @param @return    设定文件
   
   * @return Blog    返回类型
   
   * @throws
    */
   public Blog findBlogById(int blogId);

}

 

package com.pb.mybatis.mapper;import java.util.List;import com.pb.mybatis.po.Posts;public interface PostsMapper {    /**
    *
   
   * @Title: findPostsByBlogId
   
   * @Description: TODO(根据BLOGID查找文章列表)
   
   * @param @param blogId
   * @param @return    设定文件
   
   * @return List    返回类型
   
   * @throws
    */
   public List findPostsByBlogId(int blogId);
}

 

 

 

 

四、建立mapper.xml与confinguration.xml

4.1、相对应的mapper.xml

AuthorMapper.xml

 

PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">select * from author
where author_id=#{id}

 

 

 

BlogMapper.xml

 

PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">SELECT * FROM blog
WHERE blog_id=#{blogId}

 

 

 

PostsMapper.xml

 

PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">select * from posts
where blog_id=#{blogId}

 

 

 

 

4.2、configuration.xml

db.properties

 

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/mybatis?character=utf8
username=root
password=root

 

 

开启延时加载，同时关闭立即加载

 

 

PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
   
   
   
   
   
   
   
   
   
   

 

 

 

 

五、测试

5.1、JUNIT

 

package com.pb.mybatis.mapper;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 org.junit.Before;import org.junit.Test;import com.pb.mybatis.po.Blog;import com.pb.mybatis.po.Posts;public class BlogMapperTest {    private SqlSessionFactory sqlSessionFactory;

   @Before    public void setUp() throws Exception {
       String config="configuration.xml";
       InputStream resource=Resources.getResourceAsStream(config);
       sqlSessionFactory=new SqlSessionFactoryBuilder().build(resource);
   }    /**
    *
   
   * @Title: testFindBlogs
   
   * @Description: TODO(延时加载)
   
   * @param     设定文件
   
   * @return void    返回类型
   
   * @throws
    */
   @Test    public void testFindBlogById() {        //建立会话
       SqlSession sqlSession=sqlSessionFactory.openSession();        //获取Mapper接口对象
       BlogMapper blogMapper=sqlSession.getMapper(BlogMapper.class);        //调用Mapper方法
       Blog blog=blogMapper.findBlogById(1);
       
       System.out.println(blog.getBlogId()+"..."+blog.getBlogTitle());
       System.out.println("===========开始延时加载作者Author===========");
       System.out.println(blog.getAuthor());
       System.out.println("===========开始延时加载文章===========");
       List list=blog.getPostsList();        /*int count=0;
       for(Posts p:list){
           System.out.println("count+"+count++);
           System.out.println(p.getPostId());
           System.out.println(p.getPostTitle());
           System.out.println(p.getPostBody());
           System.out.println(p.getCreateTime());
           System.out.println(p.getBlogId());
       }*/
       
   }

}

 

结果：

DEBUG [main] - ==>  Preparing: SELECT * FROM blog WHERE blog_id=? DEBUG [main] - ==> Parameters: 1(Integer)
DEBUG [main] - <== Total: 1
1...小张的Blog===========开始延时加载作者Author===========DEBUG [main] - ==>  Preparing: select * from author where author_id=? DEBUG [main] - ==> Parameters: 1(Integer)
DEBUG [main] - <== Total: 1Author [authorId=1, authorUserName=张三, authorPassword=123456, authorEmail=123@qq.com, authroBio=张三是个新手，刚开始注册, registerTime=Thu Oct 29 10:23:59 CST 2015]===========开始延时加载文章===========DEBUG [main] - ==>  Preparing: select * from posts where blog_id=? DEBUG [main] - ==> Parameters: 1(Integer)
DEBUG [main] - <== Total: 2

六、一级缓存

6.1、mybatis一级缓存

mybatis，默认开启了一级缓存，sqlSession中默认有一个hashMap

当查询时，先去hashMap中查找，

如果有就直接，取出，不再操作数据库

如果没有就去数据库查找，并放在haspMap中

当做事物时，如添加，删除，修改，后有commit时会清空一级缓存

sqlSession是互不影响的，一级缓存

6.2、还是上级的例子

测试:查询用户

package com.pb.mybatis.mapper;import static org.junit.Assert.*;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;import org.junit.Before;import org.junit.Test;import com.pb.mybatis.po.Author;public class AuthorMapperTest { private SqlSessionFactory sqlSessionFactory;

@Before public void setUp() throws Exception {
String config="configuration.xml";
InputStream resource=Resources.getResourceAsStream(config);
sqlSessionFactory=new SqlSessionFactoryBuilder().build(resource);
}

@Test public void testFindAuthorById() { //获取会话工厂
SqlSession sqlSession=sqlSessionFactory.openSession();
AuthorMapper authorMapper=sqlSession.getMapper(AuthorMapper.class); //第一次查询
Author author1=authorMapper.findAuthorById(2);
System.out.println(author1); //再次查询同样的
Author author2=authorMapper.findAuthorById(2);
System.out.println(author2);
//再次查询不的同样的
Author author3=authorMapper.findAuthorById(4);
System.out.println(author3);
}

}

结果：

DEBUG [main] - ==>  Preparing: select * from author where author_id=? DEBUG [main] - ==> Parameters: 2(Integer)
DEBUG [main] - <== Total: 1Author [authorId=2, authorUserName=李四, authorPassword=123asf, authorEmail=lisi@163.com, authroBio=魂牵梦萦 , registerTime=Thu Oct 29 10:24:29 CST 2015]
Author [authorId=2, authorUserName=李四, authorPassword=123asf, authorEmail=lisi@163.com, authroBio=魂牵梦萦 , registerTime=Thu Oct 29 10:24:29 CST 2015]
DEBUG [main] - ==>  Preparing: select * from author where author_id=? DEBUG [main] - ==> Parameters: 4(Integer)
DEBUG [main] - <== Total: 1Author [authorId=4, authorUserName=赵六, authorPassword=123098sdfa, authorEmail=zhaoliu@qq.com, authroBio=花午骨, registerTime=Thu Oct 29 10:26:09 CST 2015]

6.3、当查询后，做事务，再查询第一次的

接口中做添加方法

/**
*

* @Title: addAuthor

* @Description: TODO(添加)

* @param @param author
* @param @return 设定文件

* @return int 返回类型

* @throws
*/
public int addAuthor(Author author);

mapper.xml中做同样的select

INSERT INTO author(author_username,author_password,author_email,author_bio)
VALUES(#{authorUserName},#{authorPassword},#{authorEmail},#{authroBio})

 

 

 

测试

 

package com.pb.mybatis.mapper;import static org.junit.Assert.*;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;import org.junit.Before;import org.junit.Test;import com.pb.mybatis.po.Author;public class AuthorMapperTest {    private SqlSessionFactory sqlSessionFactory;

   @Before    public void setUp() throws Exception {
       String config="configuration.xml";
       InputStream resource=Resources.getResourceAsStream(config);
       sqlSessionFactory=new SqlSessionFactoryBuilder().build(resource);
   }

   @Test    public void testFindAuthorById() {        //获取会话工厂
       SqlSession sqlSession=sqlSessionFactory.openSession();
       AuthorMapper authorMapper=sqlSession.getMapper(AuthorMapper.class);        //第一次查询
       Author author1=authorMapper.findAuthorById(2);
       System.out.println(author1);
       System.out.println("=======下面有事务处理========");
       Author newAuthor=new Author();
       newAuthor.setAuthorEmail("qq.com@qq.com");
       newAuthor.setAuthorPassword("fdsfds");
       newAuthor.setAuthorUserName("郭靖");
       newAuthor.setAuthroBio("射雕英雄传");        int num=authorMapper.addAuthor(newAuthor);
       sqlSession.commit();
       
       System.out.println(newAuthor.getAuthorId());
       System.out.println("num="+num);
       System.out.println("再次查询");        //再次查询同样的
       Author author2=authorMapper.findAuthorById(2);
       System.out.println(author2);
   
   }

   

}

 

 

 

结果：

 

DEBUG [main] - ==>  Preparing: select * from author where author_id=? DEBUG [main] - ==> Parameters: 2(Integer)
DEBUG [main] - <== Total: 1Author [authorId=2, authorUserName=李四, authorPassword=123asf, authorEmail=lisi@163.com, authroBio=魂牵梦萦 , registerTime=Thu Oct 29 10:24:29 CST 2015]=======下面有事务处理========DEBUG [main] - ==>  Preparing: INSERT INTO author(author_username,author_password,author_email,author_bio) VALUES(?,?,?,?)
DEBUG [main] - ==> Parameters: 郭靖(String), fdsfds(String), qq.com@qq.com(String), 射雕英雄传(String)
DEBUG [main] - <== Updates: 1DEBUG [main] - Committing JDBC Connection [com.mysql.jdbc.JDBC4Connection@42bb0406]11num=1再次查询
DEBUG [main] - ==>  Preparing: select * from author where author_id=? DEBUG [main] - ==> Parameters: 2(Integer)
DEBUG [main] - <==      Total: 1Author [authorId=2, authorUserName=李四, authorPassword=123asf, authorEmail=lisi@163.com, authroBio=魂牵梦萦 , registerTime=Thu Oct 29 10:24:29 CST 2015]

 

 

 

 

 

七、二级缓存

7.1、mybatis二级缓存与一级缓存

sqlSession是互不影响的，一级缓存

Mapper(namespace)是二级缓存

多个sqlSession可以共享一个Mapper的二级缓存区域

二级缓存按namespace分，其它的mapper也有自己的二级缓存区域namespace

第一个namespace的mapper都有一个二级缓存区域，2个mapper的namespace如果相同，这2个mapper执行sql查询数据将存在相同的二级缓存区域中.

 

7.2、开启二级缓存

1.二级缓存是mapper范围级别的，除了在configuration.xml设置二级缓存的总开关，还在在个体的mapper.xml中开启二级缓存

 

 

2.mapper对就的pojo类，实现序列化

3.在authorMapper中开启二级缓存

 

 

 

 

7.3、测试

 

@Test    public void testCache() {        // 获取会话工厂
       SqlSession sqlSession1 = sqlSessionFactory.openSession();
       AuthorMapper authorMapper1 = sqlSession1.getMapper(AuthorMapper.class);        // 第一次查询
       Author author1 = authorMapper1.findAuthorById(2);        //必须关闭不数据无法写到缓存区域        sqlSession1.close();        // 获取会话工厂
       /*SqlSession sqlSession2 = sqlSessionFactory.openSession();
       AuthorMapper authorMapper2 = sqlSession2.getMapper(AuthorMapper.class);
       sqlSession2.close();*/
       // 获取会话工厂
       SqlSession sqlSession3 = sqlSessionFactory.openSession();
       AuthorMapper authorMapper3 = sqlSession3.getMapper(AuthorMapper.class);        // 第一次查询
       Author author3 = authorMapper3.findAuthorById(2);
       sqlSession3.close();
   }

 

DEBUG [main] - Cache Hit Ratio [com.pb.mybatis.mapper.AuthorMapper]: 0.0DEBUG [main] - Opening JDBC Connection
DEBUG [main] - Created connection 873769339.
DEBUG [main] - Setting autocommit to false on JDBC Connection [com.mysql.jdbc.JDBC4Connection@3414a97b]
DEBUG [main] - ==>  Preparing: select * from author where author_id=? DEBUG [main] - ==> Parameters: 2(Integer)
DEBUG [main] - <== Total: 1DEBUG [main] - Resetting autocommit to true on JDBC Connection [com.mysql.jdbc.JDBC4Connection@3414a97b]
DEBUG [main] - Closing JDBC Connection [com.mysql.jdbc.JDBC4Connection@3414a97b]
DEBUG [main] - Returned connection 873769339 to pool.
DEBUG [main] - Cache Hit Ratio [com.pb.mybatis.mapper.AuthorMapper]: 0.5

中间增加commit操作

@Test public void testCache() { // 获取会话工厂
SqlSession sqlSession1 = sqlSessionFactory.openSession();
AuthorMapper authorMapper1 = sqlSession1.getMapper(AuthorMapper.class); // 第一次查询
Author author1 = authorMapper1.findAuthorById(2); //必须关闭不数据无法写到缓存区域 sqlSession1.close(); // 获取会话工厂
SqlSession sqlSession2 = sqlSessionFactory.openSession();
AuthorMapper authorMapper2 = sqlSession2.getMapper(AuthorMapper.class);
Author author2 = authorMapper2.findAuthorById(2); //更新
author2.setAuthorUserName("董事长");
author2.setAuthroBio("公司");
authorMapper2.updateAuthor(author2); //commit会清空缓存区域 sqlSession2.commit();
sqlSession2.close(); // 获取会话工厂
SqlSession sqlSession3 = sqlSessionFactory.openSession();
AuthorMapper authorMapper3 = sqlSession3.getMapper(AuthorMapper.class); // 第一次查询
Author author3 = authorMapper3.findAuthorById(2);
sqlSession3.close();
}

结果：

DEBUG [main] - Cache Hit Ratio [com.pb.mybatis.mapper.AuthorMapper]: 0.0DEBUG [main] - Opening JDBC Connection
DEBUG [main] - Created connection 873769339.
DEBUG [main] - Setting autocommit to false on JDBC Connection [com.mysql.jdbc.JDBC4Connection@3414a97b]
DEBUG [main] - ==>  Preparing: select * from author where author_id=? DEBUG [main] - ==> Parameters: 2(Integer)
DEBUG [main] - <== Total: 1DEBUG [main] - Resetting autocommit to true on JDBC Connection [com.mysql.jdbc.JDBC4Connection@3414a97b]
DEBUG [main] - Closing JDBC Connection [com.mysql.jdbc.JDBC4Connection@3414a97b]
DEBUG [main] - Returned connection 873769339 to pool.
DEBUG [main] - Cache Hit Ratio [com.pb.mybatis.mapper.AuthorMapper]: 0.5DEBUG [main] - Opening JDBC Connection
DEBUG [main] - Checked out connection 873769339 from pool.
DEBUG [main] - Setting autocommit to false on JDBC Connection [com.mysql.jdbc.JDBC4Connection@3414a97b]
DEBUG [main] - ==>  Preparing: update author SET author_username=?, author_password=?, author_email=?, author_bio=?, register_time=? where author_id=? DEBUG [main] - ==> Parameters: 董事长(String), 123asf(String), lisi@163.com(String), 公司(String), 2015-10-29 10:24:29.0(Timestamp), 2(Integer)
DEBUG [main] - <== Updates: 1DEBUG [main] - Committing JDBC Connection [com.mysql.jdbc.JDBC4Connection@3414a97b]
DEBUG [main] - Resetting autocommit to true on JDBC Connection [com.mysql.jdbc.JDBC4Connection@3414a97b]
DEBUG [main] - Closing JDBC Connection [com.mysql.jdbc.JDBC4Connection@3414a97b]
DEBUG [main] - Returned connection 873769339 to pool.
DEBUG [main] - Cache Hit Ratio [com.pb.mybatis.mapper.AuthorMapper]: 0.3333333333333333DEBUG [main] - Opening JDBC Connection
DEBUG [main] - Checked out connection 873769339 from pool.
DEBUG [main] - Setting autocommit to false on JDBC Connection [com.mysql.jdbc.JDBC4Connection@3414a97b]
DEBUG [main] - ==>  Preparing: select * from author where author_id=? DEBUG [main] - ==> Parameters: 2(Integer)
DEBUG [main] - <== Total: 1DEBUG [main] - Resetting autocommit to true on JDBC Connection [com.mysql.jdbc.JDBC4Connection@3414a97b]
DEBUG [main] - Closing JDBC Connection [com.mysql.jdbc.JDBC4Connection@3414a97b]
DEBUG [main] - Returned connection 873769339 to pool.

八、Mybatis与ehcache整合

8.1、把jar包导入项目

8.2、建立ehcache.xml

ehcache.xml

xsi:noNamespaceSchemaLocation="../config/ehcache.xsd">
   
    maxElementsInMemory="1000"
maxElementsOnDisk="10000000"
eternal="false"
overflowToDisk="false"
timeToIdleSeconds="120"
timeToLiveSeconds="120"
diskExpiryThreadIntervalSeconds="120"
memoryStoreEvictionPolicy="LRU">
   

 

 

 

8.3、在mapper的cache中指定type

 

 

 

 

8.4、测试

 

@Test    public void testCache() {        // 获取会话工厂
       SqlSession sqlSession1 = sqlSessionFactory.openSession();
       AuthorMapper authorMapper1 = sqlSession1.getMapper(AuthorMapper.class);        // 第一次查询
       Author author1 = authorMapper1.findAuthorById(2);        //必须关闭不数据无法写到缓存区域        sqlSession1.close();        // 获取会话工厂
       SqlSession sqlSession2 = sqlSessionFactory.openSession();
       AuthorMapper authorMapper2 = sqlSession2.getMapper(AuthorMapper.class);
       Author author2 = authorMapper2.findAuthorById(2);        //更新
       author2.setAuthorUserName("董事长");
       author2.setAuthroBio("公司");
       authorMapper2.updateAuthor(author2);        //commit会清空缓存区域        sqlSession2.commit();
       sqlSession2.close();        // 获取会话工厂
       SqlSession sqlSession3 = sqlSessionFactory.openSession();
       AuthorMapper authorMapper3 = sqlSession3.getMapper(AuthorMapper.class);        // 第一次查询
       Author author3 = authorMapper3.findAuthorById(2);
       sqlSession3.close();
   }

 

 

 

结果：

 

DEBUG [main] - Configuring ehcache from ehcache.xml found in the classpath: file:/E:/mywork/MybatisDemo2/bin/ehcache.xml
DEBUG [main] - Configuring ehcache from URL: file:/E:/mywork/MybatisDemo2/bin/ehcache.xml
DEBUG [main] - Configuring ehcache from InputStream
DEBUG [main] - Ignoring ehcache attribute xmlns:xsi
DEBUG [main] - Ignoring ehcache attribute xsi:noNamespaceSchemaLocation
DEBUG [main] - Disk Store Path: F:\develop\ehcache
DEBUG [main] - Creating new CacheManager with default config
DEBUG [main] - propertiesString is null.
DEBUG [main] - No CacheManagerEventListenerFactory class specified. Skipping...
DEBUG [main] - No BootstrapCacheLoaderFactory class specified. Skipping...
DEBUG [main] - CacheWriter factory not configured. Skipping...
DEBUG [main] - No CacheExceptionHandlerFactory class specified. Skipping...
DEBUG [main] - Initialized net.sf.ehcache.store.NotifyingMemoryStore for com.pb.mybatis.mapper.AuthorMapper
DEBUG [main] - Initialised cache: com.pb.mybatis.mapper.AuthorMapper
DEBUG [main] - CacheDecoratorFactory not configured for defaultCache. Skipping for 'com.pb.mybatis.mapper.AuthorMapper'.
DEBUG [main] - Cache Hit Ratio [com.pb.mybatis.mapper.AuthorMapper]: 0.0DEBUG [main] - Opening JDBC Connection
DEBUG [main] - Created connection 1286943672.
DEBUG [main] - Setting autocommit to false on JDBC Connection [com.mysql.jdbc.JDBC4Connection@4cb533b8]
DEBUG [main] - ==>  Preparing: select * from author where author_id=? DEBUG [main] - ==> Parameters: 2(Integer)
DEBUG [main] - <== Total: 1DEBUG [main] - Resetting autocommit to true on JDBC Connection [com.mysql.jdbc.JDBC4Connection@4cb533b8]
DEBUG [main] - Closing JDBC Connection [com.mysql.jdbc.JDBC4Connection@4cb533b8]
DEBUG [main] - Returned connection 1286943672 to pool.
DEBUG [main] - Cache Hit Ratio [com.pb.mybatis.mapper.AuthorMapper]: 0.5DEBUG [main] - Opening JDBC Connection
DEBUG [main] - Checked out connection 1286943672 from pool.
DEBUG [main] - Setting autocommit to false on JDBC Connection [com.mysql.jdbc.JDBC4Connection@4cb533b8]
DEBUG [main] - ==>  Preparing: update author SET author_username=?, author_password=?, author_email=?, author_bio=?, register_time=? where author_id=? DEBUG [main] - ==> Parameters: 董事长(String), 123asf(String), lisi@163.com(String), 公司(String), 2015-10-29 10:24:29.0(Timestamp), 2(Integer)
DEBUG [main] - <== Updates: 1DEBUG [main] - Committing JDBC Connection [com.mysql.jdbc.JDBC4Connection@4cb533b8]
DEBUG [main] - Resetting autocommit to true on JDBC Connection [com.mysql.jdbc.JDBC4Connection@4cb533b8]
DEBUG [main] - Closing JDBC Connection [com.mysql.jdbc.JDBC4Connection@4cb533b8]
DEBUG [main] - Returned connection 1286943672 to pool.
DEBUG [main] - Cache Hit Ratio [com.pb.mybatis.mapper.AuthorMapper]: 0.3333333333333333DEBUG [main] - Opening JDBC Connection
DEBUG [main] - Checked out connection 1286943672 from pool.
DEBUG [main] - Setting autocommit to false on JDBC Connection [com.mysql.jdbc.JDBC4Connection@4cb533b8]
DEBUG [main] - ==>  Preparing: select * from author where author_id=? DEBUG [main] - ==> Parameters: 2(Integer)
DEBUG [main] - <==      Total: 1DEBUG [main] - Resetting autocommit to true on JDBC Connection [com.mysql.jdbc.JDBC4Connection@4cb533b8]
DEBUG [main] - Closing JDBC Connection [com.mysql.jdbc.JDBC4Connection@4cb533b8]
DEBUG [main] - Returned connection 1286943672 to pool.

 以上就是MyBatis入门（五）---延时加载、缓存的内容，更多相关内容请关注PHP中文网（www.php.cn）！