MyBatis入门（二）---一对一，一对多

一、创建数据库表

1.1、创建数据表同时插入数据

 

/*
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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IDprivate 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)* <p>Title: toString</p>* <p>Description:重写toString方法 </p>* @return* @see java.lang.Object#toString()*/@Overridepublic 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

 

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configurationPUBLIC "-//mybatis.org//DTD Config 3.0//EN""http://mybatis.org/dtd/mybatis-3-config.dtd"><configuration>
<properties resource="db.properties" />
<typeAliases>
<!--使用默认别名  -->
<package name="com.pb.mybatis.po"/>
</typeAliases>
<environments default="development">
<environment id="development"><transactionManager type="JDBC"/><dataSource type="POOLED"><property name="driver" value="${jdbc.driver}"/><property name="url" value="${jdbc.url}"/><property name="username" value="${jdbc.username}"/><property name="password" value="${jdbc.password}"/></dataSource>
</environment>
</environments>
<mappers>
<!-- 加载映射 --><package name="com.pb.mybatis.mapper"/>
</mappers>
</configuration>

 

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<Author>*/public List<Author> 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

 

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.pb.mybatis.mapper.AuthorMapper">
<!--使用resultMap映射  type使用别名，-->
<resultMap type="Author" id="authorResultMap">
<!--主键  -->
<id property="authorId" column="author_id"/>
<!--普通属性与表中的字段对应  -->
<result property="authorUserName" column="author_username"/>
<result property="authorPassword" column="author_password"/>
<result property="authorEmail" column="author_email"/>
<result property="authorBio" column="author_bio"/>
<result property="registerTime" column="register_time"/>
</resultMap><!--根据查找一个用户  -->
<select id="findAuthorById" parameterType="int" resultMap="authorResultMap">
SELECT * FROM author
WHERE author_id=#{authorId}
</select><!-- 根据用户名，模糊查询 --><select id="findAuthorByName" parameterType="String" resultMap="authorResultMap">
SELECT * FROM author
WHERE author_username LIKE "%"#{name}"%"
</select><!--添加用户  useGeneratedKeys="true" 使用数据库自增序列keyProperty="authorId"将主键返回
#号中写PO类中的属性
-->
<insert id="addAuthor" parameterType="Author" useGeneratedKeys="true" keyProperty="authorId">
INSERT INTO author(author_username,author_password,author_email,author_bio,register_time) 
VALUES(#{authorUserName},#{authorPassword},#{authorEmail},#{authorBio},#{registerTime})
</insert>
<!--修改用户  -->
<update id="updateAuthor" parameterType="Author">
update author 
set 
author_username=#{authorUserName},
author_password=#{authorPassword},
author_email=#{authorEmail},
author_bio=#{authorBio},
register_time=#{registerTime}
where author_id=#{authorId}
</update>
<!--删除用户  根据ID-->
<delete id="deleteAuthor" parameterType="int">
delete from author
where author_id=#{authorId}
</delete>
</mapper>

 

 

 

 

 

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*/@Beforepublic 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*/@Testpublic 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*/@Testpublic void testFindAuthorByName() {//获取会话SqlSession sqlSession=sqlSessionFactory.openSession();//Mapper接口AuthorMapper authorMapper=sqlSession.getMapper(AuthorMapper.class);//调用方法List<Author> 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*/@Testpublic 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*/@Testpublic 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*/@Testpublic 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IDprivate 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)* <p>Title: toString</p>* <p>Description: 重写toString方法</p>* @return* @see java.lang.Object#toString()*/@Overridepublic 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<Blog>*/public List<Blog> 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

 

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.pb.mybatis.mapper.BlogMapper">
<!--使用ResultMap  -->
<resultMap type="Blog" id="blogResultMap">
<!--主键  -->
<id property="blogId" column="blog_id"/>
<!--标题  -->
<result property="blogTitle" column="blog_title"/>
<!--一对一关联   第一种-->
<association property="author" resultMap="authorResultMap"/><!--  第二种
把作者类再映射在一个resultMap中
<association property="author" resultMap="authorResultMap">
<id property="authorId" column="author_id"/>
普通属性与表中的字段对应 
<result property="authorUserName" column="author_username"/>
<result property="authorPassword" column="author_password"/>
<result property="authorEmail" column="author_email"/>
<result property="authorBio" column="author_bio"/>
<result property="registerTime" column="register_time"/>
</association> 
-->
</resultMap><!--使用resultMap映射  type使用别名，单独使用Author关联-->
<resultMap type="Author" id="authorResultMap">
<!--主键  -->
<id property="authorId" column="author_id"/>
<!--普通属性与表中的字段对应  -->
<result property="authorUserName" column="author_username"/>
<result property="authorPassword" column="author_password"/>
<result property="authorEmail" column="author_email"/>
<result property="authorBio" column="author_bio"/>
<result property="registerTime" column="register_time"/>
</resultMap>
<!--  根据ID查询-->
<select id="findBlogById" parameterType="int" resultMap="blogResultMap">
SELECT blog.blog_id,blog.blog_title,author.author_id,author.author_username,author.author_password,author.author_email,author.author_bio,author.register_time
FROM blog,author    
WHERE blog.author_id=author.author_id
AND blog.blog_id=#{blogId}
</select>
<!-- 根据名字查询 -->
<select id="findBlogByName" parameterType="String" resultMap="blogResultMap">
SELECT blog.blog_id,blog.blog_title,author.author_id,author.author_username,author.author_password,author.author_email,author.author_bio,author.register_time
FROM blog,author    
WHERE blog.author_id=author.author_id
AND blog_title LIKE "%"#{blogTitle}"%"
</select>
<!-- 添加Blog -->
<insert id="addBlog" parameterType="Blog" useGeneratedKeys="true" keyProperty="blogId">
INSERT INTO blog(blog_title,author_id)
VALUES(#{blogTitle},#{author.authorId})
</insert>
<!--修改  -->
<update id="updateBlog" parameterType="Blog">
UPDATE blog 
SET blog_title=#{blogTitle},
author_id=#{author.authorId}
WHERE blog_id=#{blogId}
</update>
<!--删除  -->
<delete id="deleteBlog" parameterType="int">
delete from blog where blog_id=#{blogId}
</delete></mapper>

 

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;@Beforepublic 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)}.*/@Testpublic 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)}.*/@Testpublic void testFindBlogByName() {//获取会话SqlSession sqlSession=sqlSessionFactory.openSession();//Mapper接口BlogMapper blogMapper=sqlSession.getMapper(BlogMapper.class);//调用方法List<Blog> 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)}.*/@Testpublic 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)}.*/@Testpublic 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)}.*/@Testpublic 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IDprivate 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)* <p>Title: toString</p>* <p>Description:重写toString方法</p>* @return* @see java.lang.Object#toString()*/@Overridepublic 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IDprivate int blogId;//标题private String blogTitle;//博客作者private Author author;//文章Listprivate List<Posts> 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<Posts> getPosts() {return posts;}/*** @param posts the posts to set*/public void setPosts(List<Posts> posts) {this.posts = posts;}/** (non Javadoc)* <p>Title: toString</p>* <p>Description: </p>* @return* @see java.lang.Object#toString()*/@Overridepublic String toString() {return "Blog [blogId=" + blogId + ", blogTitle=" + blogTitle+ ", author=" + author + ", posts=" + posts + "]";}}

 

5.3、修改blogMapper.xml

 

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.pb.mybatis.mapper.BlogMapper">
<!--使用ResultMap  -->
<resultMap type="Blog" id="blogResultMap">
<!--主键  -->
<id property="blogId" column="blog_id"/>
<!--标题  -->
<result property="blogTitle" column="blog_title"/>
<!--一对一关联   第一种-->
<association property="author" resultMap="authorResultMap"/>
<!--一对多关联  -->
<collection property="posts" resultMap="postsResultMap" ofType="Posts"/><!--  第二种
把作者类再映射在一个resultMap中
<association property="author" resultMap="authorResultMap">
<id property="authorId" column="author_id"/>
普通属性与表中的字段对应 
<result property="authorUserName" column="author_username"/>
<result property="authorPassword" column="author_password"/>
<result property="authorEmail" column="author_email"/>
<result property="authorBio" column="author_bio"/>
<result property="registerTime" column="register_time"/>
</association> 
-->
</resultMap>
<!--文章Map  -->
<resultMap type="Posts" id="postsResultMap">
<id property="postId" column="post_id"/>
<result property="postSubject" column="post_subject"/>
<result property="postBody" column="post_body"/>
<result property="createTime" column="createtime"/>
</resultMap>
<!--使用resultMap映射  type使用别名，单独使用Author关联-->
<resultMap type="Author" id="authorResultMap">
<!--主键  -->
<id property="authorId" column="author_id"/>
<!--普通属性与表中的字段对应  -->
<result property="authorUserName" column="author_username"/>
<result property="authorPassword" column="author_password"/>
<result property="authorEmail" column="author_email"/>
<result property="authorBio" column="author_bio"/>
<result property="registerTime" column="register_time"/>
</resultMap>
<!--  根据ID查询-->
<select id="findBlogById" parameterType="int" resultMap="blogResultMap">
SELECT blog.blog_id,blog.blog_title,
author.author_id,author.author_username,author.author_password,author.author_email,author.author_bio,author.register_time,
posts.post_id,posts.post_subject,posts.post_body,posts.createtime,posts.blog_id
FROM blog,author,posts    
WHERE blog.author_id=author.author_id
AND blog.blog_id=posts.blog_id
AND blog.blog_id=#{blogId}
</select>
<!-- 根据名字查询 -->
<select id="findBlogByName" parameterType="String" resultMap="blogResultMap">
SELECT blog.blog_id,blog.blog_title,author.author_id,author.author_username,author.author_password,author.author_email,author.author_bio,author.register_time
FROM blog,author    
WHERE blog.author_id=author.author_id
AND blog_title LIKE "%"#{blogTitle}"%"
</select>
<!-- 添加Blog -->
<insert id="addBlog" parameterType="Blog" useGeneratedKeys="true" keyProperty="blogId">
INSERT INTO blog(blog_title,author_id)
VALUES(#{blogTitle},#{author.authorId})
</insert>
<!--修改  -->
<update id="updateBlog" parameterType="Blog">
UPDATE blog 
SET blog_title=#{blogTitle},
author_id=#{author.authorId}
WHERE blog_id=#{blogId}
</update>
<!--删除  -->
<delete id="deleteBlog" parameterType="int">
delete from blog where blog_id=#{blogId}
</delete></mapper>

 

 

5.4、测试

测试类不变

转载于:https://www.cnblogs.com/liunanjava/p/4919752.html

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