mybatis 嵌套查询一对一

[weixin_43392489]

贴代码的来，感谢。。。

[前端小歌谣]

[前端小歌谣]

上面是数据库

[前端小歌谣]

目录结构，总实现不了

[helloworddm]

检查下看mybatis的扫描路径是否正确．

[前端小歌谣]

引用 4 楼 helloworlddm的回复:

检查下看mybatis的扫描路径是否正确．

调一下午了，等会上代码全部的

[前端小歌谣]

author类
package com.geyao.mybatis.pojo;

public class Author {
private Integer id;
private String username;
private String password;
private String email;
private String bio;
private String favouriteSection;
private String nickname;
private String realname;
public Author() {
super();
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public String getBio() {
return bio;
}
public void setBio(String bio) {
this.bio = bio;
}
public String getFavouriteSection() {
return favouriteSection;
}
public void setFavouriteSection(String favouriteSection) {
this.favouriteSection = favouriteSection;
}
public String getNickname() {
return nickname;
}
public void setNickname(String nickname) {
this.nickname = nickname;
}
public String getRealname() {
return realname;
}
public void setRealname(String realname) {
this.realname = realname;
}
public Author(Integer id, String username, String password, String email, String bio, String favouriteSection,
String nickname, String realname) {
super();
this.id = id;
this.username = username;
this.password = password;
this.email = email;
this.bio = bio;
this.favouriteSection = favouriteSection;
this.nickname = nickname;
this.realname = realname;
}



}

[前端小歌谣]

blog类
package com.geyao.mybatis.pojo;

import java.io.Serializable;

public class Blog implements Serializable {

private static final long serialVersionUID = 1L;
private Integer id;
private String title;
private Author author;
private String state;
private boolean featured;
private String style;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public Author getAuthor() {
return author;
}
public void setAuthor(Author author) {
this.author = author;
}
public String getState() {
return state;
}
public void setState(String state) {
this.state = state;
}
public boolean isFeatured() {
return featured;
}
public void setFeatured(boolean featured) {
this.featured = featured;
}
public String getStyle() {
return style;
}
public void setStyle(String style) {
this.style = style;
}
public static long getSerialversionuid() {
return serialVersionUID;
}




}

[前端小歌谣]

authormap。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">
<!-- 为这个mapper指定一个唯一的namespace，namespace的值习惯上设置成包名+sql映射文件名，这样就能够保证namespace的值是唯一的
例如namespace="me.gacl.mapping.userMapper"就是me.gacl.mapping(包名)+userMapper(userMapper.xml文件去除后缀)
-->
<mapper namespace="com.geyao.mybatis.mapper.AuthorMapper">
<resultMap type="Author" id="authorResultMap">
<id column="id" property="id" jdbcType="INTEGER"></id>

</resultMap>
<select id="selectAuthorById" parameterType="int" resultMap="authorResultMap">
select * from author where id=#{id}
</select>
</mapper>
blogmapper。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.geyao.mybatis.mapper.BlogMapper">
<resultMap type="Blog" id="blogResultMap">
<id column="id" property="id" jdbcType="INTEGER"></id>
<association property="author" column="author" javaType="Author"
select="com.geyao.mybatis.mapper.AuthorMapper.selectAuthorById">
</association>
</resultMap>

<select id="selectAuthorById" parameterType="int" resultMap="blogResultMap">
select * from Blog where id=#{id}
</select>
</mapper>

[前端小歌谣]

测试类
package com.geyao.mybatis.mapper;

import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import com.geyao.mybatis.pojo.Author;
import com.geyao.mybatis.pojo.Blog;
import com.geyao.mybatis.util.MyBatisUtil;

public class BlogMapperTest {
@Test
public void testSelectBlog() {
SqlSession session =MyBatisUtil.getSqlSession();
BlogMapper blogMapper =session.getMapper(BlogMapper.class);

Blog blog = blogMapper.selectBlogById(1);
session.close();
System.out.println(blog);
}


}

[前端小歌谣]

mybatis-config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>
<settings>
<setting name="useGeneratedKeys" value="true"/>
</settings>
<typeAliases>
<typeAlias type="com.geyao.mybatis.pojo.Blog" alias="Blog"/>
<typeAlias type="com.geyao.mybatis.pojo.Author" alias="Author"/>
</typeAliases>
<environments default="development">
<environment id="development">
<transactionManager type="JDBC" />
<!-- 配置数据库连接信息 -->
<dataSource type="POOLED">
<property name="driver" value="com.mysql.cj.jdbc.Driver" />
<property name="url" value="jdbc:mysql://localhost:3306/blog_gp1701?serverTimezone=GMT%2B8" />
<property name="username" value="root" />
<property name="password" value="123" />
</dataSource>
</environment>
</environments>
<mappers>
<!-- 注册userMapper.xml文件，
userMapper.xml位于me.gacl.mapping这个包下，所以resource写成me/gacl/mapping/userMapper.xml-->
<mapper resource="com/geyao/mybatis/mapper/BlogMapper.xml"/>
<mapper resource="com/geyao/mybatis/mapper/AuthorMapper.xml"/>
</mappers>
</configuration>