MyBatis入门（二）---一对一，一对多-java教程-PHP中文网

一、创建数据库表

1.1、创建数据表同时插入数据

/*SQLyog EnterPRise v12.09 (64 bit)MySQL - 5.6.27-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=6 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');

/*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 */;

二、创建项目

2.1、创建项目并加入jar包

2.2、创建实体类以author为例

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

* @Title: Author.java

* @Package com.pb.mybatis.po

* @ClassName Author

* @Description: TODO(Blog作者类)

* @author 刘楠

* @date 2015-10-29 上午9:27:53

* @version V1.0 */public class Author { //作者ID
private int authorId;
//作者用户名
private String authorUserName;
//作者密码
private String authorPassword;
//作者邮箱
private String authorEmail;
//作者介绍
private int authorBio;
//注册时间
private Date registerTime; /**
* @return the authorId */
public int getAuthorId() { return authorId;
} /**
* @param authorId the authorId to set */
public void setAuthorId(int authorId) { this.authorId = authorId;
} /**
* @return the authorUserName */
public String getAuthorUserName() { return authorUserName;
} /**
* @param authorUserName the authorUserName to set */
public void setAuthorUserName(String authorUserName) { this.authorUserName = authorUserName;
} /**
* @return the authorPassword */
public String getAuthorPassword() { return authorPassword;
} /**
* @param authorPassword the authorPassword to set */
public void setAuthorPassword(String authorPassword) { this.authorPassword = authorPassword;
} /**
* @return the authorEmail */
public String getAuthorEmail() { return authorEmail;
} /**
* @param authorEmail the authorEmail to set */
public void setAuthorEmail(String authorEmail) { this.authorEmail = authorEmail;
} /**
* @return the authorBio */
public int getAuthorBio() { return authorBio;
} /**
* @param authorBio the authorBio to set */
public void setAuthorBio(int authorBio) { this.authorBio = authorBio;
} /**
* @return the registerTime */
public Date getRegisterTime() { return registerTime;
} /**
* @param registerTime the registerTime to set */
public void setRegisterTime(Date registerTime) { this.registerTime = registerTime;
} /** (non Javadoc)

*

Title: toString

Description:重写toString方法

* @return

* @see java.lang.Object#toString() */
@Override public String toString() { return "Author [authorId=" + authorId + ", authorUserName="
+ authorUserName + ", authorPassword=" + authorPassword + ", authorEmail=" + authorEmail + ", authorBio=" + authorBio + ", registerTime=" + registerTime + "]";
}

}

2.3、创建mybatis配置文件

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

2.4、创建实体类对象的接口以author为例

/***/package com.pb.mybatis.mapper;import java.util.List;import com.pb.mybatis.po.Author;/**

* @Title: AuthorMapper.java

* @Package com.pb.mybatis.mapper

* @ClassName AuthorMapper

* @Description: TODO(作者接口)

* @author 刘楠

* @date 2015-10-29 上午11:13:10

* @version V1.0

*/public interface AuthorMapper {
/**
*
* @Title: findById

* @Description: TODO(根据查找一个用户)

* @param id
* @return Author */
public Author findAuthorById(int authorId);
/**
*
* @Title: findByName

* @Description: TODO(根据用户名，模糊查询)

* @param name
* @return List */
public List findAuthorByName(String name);
/**
*
* @Title: addAuthor

* @Description: TODO(添加作者)

* @param author
* @return int */
public int addAuthor(Author author);
/**
*
* @Title: updateAuthor

* @Description: TODO(修改用户)

* @param authro
* @return int */
public int updateAuthor(Author authro);
/**
*
* @Title: deleteAturho

* @Description: TODO(根据ID删除作者)

* @param id
* @return int */
public int deleteAuthor(int authorId);

}

2.5、创建接口对应的mapper.xm以author为例

PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">INSERT INTO author(author_username,author_password,author_email,author_bio,register_time)
VALUES(#{authorUserName},#{authorPassword},#{authorEmail},#{authorBio},#{registerTime})update author
set
author_username=#{authorUserName},
author_password=#{authorPassword},
author_email=#{authorEmail},
author_bio=#{authorBio},
register_time=#{registerTime}
where author_id=#{authorId}delete from author
where author_id=#{authorId}

三、简单实现增删改查

3.1、测试类以author为例

/***/package com.pb.mybatis.mapper;import java.io.InputStream;import java.util.Date;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.Author;/**

* @Title: AuthorMapperTest.java

* @Package com.pb.mybatis.mapper

* @ClassName AuthorMapperTest

* @Description: TODO(测试)

* @author 刘楠

* @date 2015-10-29 上午11:57:21

* @version V1.0

*/public class AuthorMapperTest {
private SqlSessionFactory sqlSessionFactory;
/**
*
* @Title: setUp

* @Description: TODO(在每个方法前执行的方法)

* @throws Exception void */
@Before public void setUp() throws Exception {
String resource="configuration.xml";
InputStream in=Resources.getResourceAsStream(resource); //获取会话工厂
sqlSessionFactory=new SqlSessionFactoryBuilder().build(in);
} /**
*
* @Title: testFindAuthorById

* @Description: TODO(根据查找一个用户)
void */
@Test public void testFindAuthorById() { //获取会话
SqlSession sqlSession=sqlSessionFactory.openSession(); //Mapper接口
AuthorMapper authorMapper=sqlSession.getMapper(AuthorMapper.class); //调用方法
Author author=authorMapper.findAuthorById(2);
System.out.println(author); //关闭会话 sqlSession.close();
} /**
*
* @Title: testFindAuthorByName

* @Description: TODO(根据用户名，模糊查询)
void */
@Test public void testFindAuthorByName() { //获取会话
SqlSession sqlSession=sqlSessionFactory.openSession(); //Mapper接口
AuthorMapper authorMapper=sqlSession.getMapper(AuthorMapper.class); //调用方法
List authors=authorMapper.findAuthorByName("张");
System.out.println(authors); //关闭会话 sqlSession.close(); for(Author a:authors){
System.out.println(a.toString());
}
} /**
*
* @Title: testAddAuthor

* @Description: TODO(添加作者)
void */
@Test public void testAddAuthor() { //获取会话
SqlSession sqlSession=sqlSessionFactory.openSession(); //Mapper接口
AuthorMapper authorMapper=sqlSession.getMapper(AuthorMapper.class); //调用方法
Author author=new Author();
author.setAuthorUserName("不知道");
author.setAuthorPassword("1234567890");
author.setAuthorEmail("123456@qq.com");
author.setAuthorBio("知道是个什么");
author.setRegisterTime(new Date()); int num=authorMapper.addAuthor(author);
System.out.println("num="+num);
System.out.println("authorId="+author.getAuthorId());
sqlSession.commit(); //关闭会话 sqlSession.close();

} /**
*
* @Title: testUpdateAuthor

* @Description: TODO(修改用户)
void */
@Test public void testUpdateAuthor() { //获取会话
SqlSession sqlSession=sqlSessionFactory.openSession(); //Mapper接口
AuthorMapper authorMapper=sqlSession.getMapper(AuthorMapper.class); //调用方法
Author author=authorMapper.findAuthorById(8);
author.setAuthorUserName("知道了");
author.setAuthorPassword("456789");
author.setAuthorEmail("456789@qq.com");
author.setAuthorBio("哈哈哈哈哈雅虎");
author.setRegisterTime(new Date()); int num=authorMapper.updateAuthor(author);
System.out.println("num="+num);
System.out.println("authorId="+author.getAuthorId());
sqlSession.commit(); //关闭会话 sqlSession.close();

} /**
*
* @Title: testDeleteAuthor

* @Description: TODO(根据ID删除作者)
void */
@Test public void testDeleteAuthor() { //获取会话
SqlSession sqlSession=sqlSessionFactory.openSession(); //Mapper接口
AuthorMapper authorMapper=sqlSession.getMapper(AuthorMapper.class); //调用方法

int num=authorMapper.deleteAuthor(10);
System.out.println("num="+num);

sqlSession.commit(); //关闭会话 sqlSession.close();
}

}

四、实现一对一

4.1、建立Blog类

package com.pb.mybatis.po;/**

* @Title: Blog.java

* @Package com.pb.mybatis.po

* @ClassName Blog

* @Description: TODO(博客)

* @author 刘楠

* @date 2015-10-29 上午9:32:56

* @version V1.0

*/public class Blog { //博客ID
private int blogId;
//标题
private String blogTitle;
//博客作者
private Author author; /**
* @return the blogId */
public int getBlogId() { return blogId;
} /**
* @param blogId the blogId to set */
public void setBlogId(int blogId) { this.blogId = blogId;
} /**
* @return the blogTitle */
public String getBlogTitle() { return blogTitle;
} /**
* @param blogTitle the blogTitle to set */
public void setBlogTitle(String blogTitle) { this.blogTitle = blogTitle;
} /**
* @return the author */
public Author getAuthor() { return author;
} /**
* @param author the author to set */
public void setAuthor(Author author) { this.author = author;
} /** (non Javadoc)

*

Title: toString

Description: 重写toString方法

* @return

* @see java.lang.Object#toString() */
@Override public String toString() { return "Blog [blogId=" + blogId + ", blogTitle=" + blogTitle + ", author=" + author + "]";
}

}

4.2、建立BlogMapper接口

/***/package com.pb.mybatis.mapper;import java.util.List;import com.pb.mybatis.po.Author;import com.pb.mybatis.po.Blog;/**

* @Title: BlogMapper.java

* @Package com.pb.mybatis.mapper

* @ClassName BlogMapper

* @Description: TODO(用一句话描述该文件做什么)

* @author 刘楠

* @date 2015-10-29 上午11:13:21

* @version V1.0

*/public interface BlogMapper { /**
*
* @Title: findBlogById

* @Description: TODO(根据ID查找BLOG)

* @param id
* @return Blog */
public Blog findBlogById(int id);
/**
*
* @Title: findByName

* @Description: TODO(根据博客名查找)

* @param name
* @return List */
public List findBlogByName(String blogTitle);
/**
*
* @Title: addBlog

* @Description: TODO(添加博客)

* @param blog
* @return int */
public int addBlog(Blog blog);

/**
*
* @Title: updateBlog

* @Description: TODO(修改博客)

* @param blog
* @return int */
public int updateBlog(Blog blog);
/**
*
* @Title: deleteBlog

* @Description: TODO(删除博客)

* @param id
* @return int */
public int deleteBlog(int id);
}

4.3、建立mapper.xml

PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">INSERT INTO blog(blog_title,author_id)
VALUES(#{blogTitle},#{author.authorId})UPDATE blog
SET blog_title=#{blogTitle},
author_id=#{author.authorId}
WHERE blog_id=#{blogId}delete from blog where blog_id=#{blogId}

4.1、测试类

package com.pb.mybatis.mapper;import static org.junit.Assert.*;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.Author;import com.pb.mybatis.po.Blog;/**

* @Title: BlogMapperTest.java

* @Package com.pb.mybatis.mapper

* @ClassName BlogMapperTest

* @Description: TODO(用一句话描述该文件做什么)

* @author 刘楠

* @date 2015-10-29 下午3:12:52

* @version V1.0

*/public class BlogMapperTest { private SqlSessionFactory sqlSessionFactory;

@Before public void setUp() throws Exception {
String resource="configuration.xml";
InputStream in=Resources.getResourceAsStream(resource); //获取会话工厂
sqlSessionFactory=new SqlSessionFactoryBuilder().build(in);
} /**
* Test method for {@link com.pb.mybatis.mapper.BlogMapper#findBlogById(int)}. */
@Test public void testFindBlogById() { //获取会话
SqlSession sqlSession=sqlSessionFactory.openSession(); //Mapper接口
BlogMapper blogMapper=sqlSession.getMapper(BlogMapper.class); //调用方法
Blog blog=blogMapper.findBlogById(2);
System.out.println(blog); //关闭会话 sqlSession.close();
} /**
* Test method for {@link com.pb.mybatis.mapper.BlogMapper#findBlogByName(java.lang.String)}. */
@Test public void testFindBlogByName() { //获取会话
SqlSession sqlSession=sqlSessionFactory.openSession(); //Mapper接口
BlogMapper blogMapper=sqlSession.getMapper(BlogMapper.class); //调用方法
List blogs=blogMapper.findBlogByName("小");
System.out.println(blogs); //关闭会话 sqlSession.close();
} /**
* Test method for {@link com.pb.mybatis.mapper.BlogMapper#addBlog(com.pb.mybatis.po.Blog)}. */
@Test public void testAddBlog() { //获取会话
SqlSession sqlSession=sqlSessionFactory.openSession(); //Mapper接口
BlogMapper blogMapper=sqlSession.getMapper(BlogMapper.class);
Blog blog=new Blog();
blog.setBlogTitle("倚天屠龙记");
AuthorMapper authorMapper=sqlSession.getMapper(AuthorMapper.class); //调用方法
Author author=authorMapper.findAuthorById(2);
blog.setAuthor(author); int num=blogMapper.addBlog(blog);
System.out.println("num="+num);
System.out.println(blog.getBlogId());
sqlSession.commit();
sqlSession.close();
} /**
* Test method for {@link com.pb.mybatis.mapper.BlogMapper#updateBlog(com.pb.mybatis.po.Blog)}. */
@Test public void testUpdateBlog() { //获取会话
SqlSession sqlSession=sqlSessionFactory.openSession(); //Mapper接口
BlogMapper blogMapper=sqlSession.getMapper(BlogMapper.class); //调用方法
Blog blog=blogMapper.findBlogById(8);
blog.setBlogTitle("笑傲江湖");
Author author=blog.getAuthor();
author.setAuthorUserName("金庸");
AuthorMapper authorMapper=sqlSession.getMapper(AuthorMapper.class); int authorNum=authorMapper.updateAuthor(author); int num=blogMapper.updateBlog(blog);
System.out.println("authorNum="+authorNum);
System.out.println("num="+num);
sqlSession.commit(); //关闭会话 sqlSession.close();
} /**
* Test method for {@link com.pb.mybatis.mapper.BlogMapper#deleteBlog(int)}. */
@Test public void testDeleteBlog() { //获取会话
SqlSession sqlSession=sqlSessionFactory.openSession(); //Mapper接口
BlogMapper blogMapper=sqlSession.getMapper(BlogMapper.class); int num=blogMapper.deleteBlog(11);
System.out.println("num="+num);
sqlSession.commit();
sqlSession.close();
}

}

五、一对多

5.1、建立Posts类

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

* @Title: Posts.java

* @Package com.pb.mybatis.po

* @ClassName Posts

* @Description: TODO(Blog文章)

* @author 刘楠

* @date 2015-10-29 上午9:31:22

* @version V1.0

*/public class Posts { //文章ID
private int postId;
//文件主题
private String postSubject;
//主体内容
private String postBody; //文章建立时间
private Date createTime;

/**
* @return the postId */
public int getPostId() { return postId;
} /**
* @param postId the postId to set */
public void setPostId(int postId) { this.postId = postId;
} /**
* @return the postSubject */
public String getPostSubject() { return postSubject;
} /**
* @param postSubject the postSubject to set */
public void setPostSubject(String postSubject) { this.postSubject = postSubject;
} /**
* @return the postBody */
public String getPostBody() { return postBody;
} /**
* @param postBody the postBody to set */
public void setPostBody(String postBody) { this.postBody = postBody;
} /**
* @return the createTime */
public Date getCreateTime() { return createTime;
} /**
* @param createTime the createTime to set */
public void setCreateTime(Date createTime) { this.createTime = createTime;
} /** (non Javadoc)

*

Title: toString

Description:重写toString方法

* @return

* @see java.lang.Object#toString() */
@Override public String toString() { return "Posts [postId=" + postId + ", postSubject=" + postSubject + ", postBody=" + postBody +", createTime="
+ createTime + "]";
}

}

5.2、在blog类中添加List

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

* @Title: Blog.java

* @Package com.pb.mybatis.po

* @ClassName Blog

* @Description: TODO(博客)

* @author 刘楠

* @date 2015-10-29 上午9:32:56

* @version V1.0

*/public class Blog { //博客ID
private int blogId;
//标题
private String blogTitle;
//博客作者
private Author author;
//文章List
private List posts; /**
* @return the blogId */
public int getBlogId() { return blogId;
} /**
* @param blogId the blogId to set */
public void setBlogId(int blogId) { this.blogId = blogId;
} /**
* @return the blogTitle */
public String getBlogTitle() { return blogTitle;
} /**
* @param blogTitle the blogTitle to set */
public void setBlogTitle(String blogTitle) { this.blogTitle = blogTitle;
} /**
* @return the author */
public Author getAuthor() { return author;
} /**
* @param author the author to set */
public void setAuthor(Author author) { this.author = author;
} /**
* @return the posts */
public List getPosts() { return posts;
} /**
* @param posts the posts to set */
public void setPosts(List posts) { this.posts = posts;
} /** (non Javadoc)

*

Title: toString

Description:

* @return

* @see java.lang.Object#toString() */
@Override public String toString() { return "Blog [blogId=" + blogId + ", blogTitle=" + blogTitle + ", author=" + author + ", posts=" + posts + "]";
}

}

5.3、修改blogMapper.xml

5.4、测试

测试类不变

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