MyBatis
- 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。
数据库的基本 增删改查
select 按照主键查询
//select 按照主键查询
@Select("""
select id,user_id,title,summary,read_count,create_time,update_time
from article where id = #{ArticleID}
""")
// 查询结果集和PO映射 列和PO结果映射
@Results(id = "BaseArticleMap", value = {
@Result(id = true, column = "id", property = "id"),
@Result(column = "user_id", property = "user_id"),
@Result(column = "title", property = "title"),
@Result(column = "summary", property = "summary"),
@Result(column = "read_count", property = "read_count"),
@Result(column = "create_time", property = "create_time"),
@Result(column = "update_time", property = "update_time"),
})
ArticlePo selectById(@Param("ArticleID") Integer id);
// Spring Test
@Autowired(required = false)
private ArticleMapper articleMapper;
@Test
void onTestSelect() {
ArticlePo articlePo = articleMapper.selectById(1);
System.out.println("articlePo = " + articlePo);
}
//打印日志
JDBC Connection [HikariProxyConnection@1971855969 wrapping com.mysql.cj.jdbc.ConnectionImpl@563ccd31] will not be managed by Spring
==> Preparing: select id,user_id,title,summary,read_count,create_time,update_time from article where id = ?
==> Parameters: 1(Integer)
<== Columns: id, user_id, title, summary, read_count, create_time, update_time
<== Row: 1, 9527, Spring Boot 核心注解, 核心注解的主要作业作用, 20, 2023-07-12 11:34:36, 2023-07-12 11:34:50
<== Total: 1
install 添加
//install
@Insert("""
INSERT INTO article (user_id, title, summary, read_count, create_time, update_time)
VALUES
(#{user_id},#{title},#{summary},#{read_count},#{create_time},#{update_time})
""")
int insertArticle(ArticlePo articlePo);
//Spring Test
@Test
void onInsertPO() {
ArticlePo articlePo = new ArticlePo();
articlePo.setUser_id(888);
articlePo.setTitle("Android OS 系统开发");
articlePo.setSummary("View,Hander,App");
articlePo.setRead_count(50);
articlePo.setCreate_time(LocalDateTime.now());
articlePo.setUpdate_time(LocalDateTime.now());
Integer rows = articleMapper.insertArticle(articlePo);
System.out.println("rows = " + rows);
}
//打印日志
==> Preparing: INSERT INTO article (user_id, title, summary, read_count, create_time, update_time) VALUES (?,?,?,?,?,?)
==> Parameters: 888(Integer), Android OS 系统开发(String), View,Hander,App(String), 50(Integer), 2023-08-14T11:23:03.394367600(LocalDateTime), 2023-08-14T11:23:03.394367600(LocalDateTime)
<== Updates: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@4f59a516]
rows = 1
update更新
@Update("""
UPDATE article set read_count = #{readCount} WHERE id = #{id}
""")
int updateArticle(int id, int readCount);
//Spring Test
@Test
void onUpdateArticle() {
Integer rows = articleMapper.updateArticle(3, 555);
System.out.println("rows = " + rows);
}
//打印日志
==> Preparing: UPDATE article set read_count = ? WHERE id = ?
==> Parameters: 555(Integer), 3(Integer)
<== Updates: 0
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@46fc522d]
rows = 0
delete删除
@Delete("""
DELETE from article where id = #{id}
""")
int deleteArticle(int id);
//Spring test
@Test
void onDeleteArticle() {
Integer rows = articleMapper.deleteArticle(3);
System.out.println("rows = " + rows);
}
//打印日志
==> Preparing: DELETE from article where id = ?
==> Parameters: 8(Integer)
<== Updates: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@7e8279e5]
rows = 1
Result查询结果转换
List<*>
@Select("""
select id,user_id,title,summary,read_count,create_time,update_time
from article where user_id = #{userId}
""")
@Results(id = "BaseArticleMap", value = {
@Result(id = true, column = "id", property = "id"),
@Result(column = "user_id", property = "user_id"),
@Result(column = "title", property = "title"),
@Result(column = "summary", property = "summary"),
@Result(column = "read_count", property = "read_count"),
@Result(column = "create_time", property = "create_time"),
@Result(column = "update_time", property = "update_time"),
})
List<ArticlePo> selectListArticle(Integer userId);
对象ArticlePo
@Select("""
select * from article where id = #{article_Id}
""")
@ResultMap(value = "BaseArticleMap")
ArticlePo selectById(Integer article_Id);
xml转换对象
- resources - mappers - ArticleMapper.xml 新建mapper类型xml转换
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.example.alee.mybatis.springmybatis.mapper.ArticleDao">
<!-- 定义ResultMap -->
<resultMap id="ActionBaseMapper" type="com.example.alee.mybatis.springmybatis.po.ArticlePo">
<id column="id" property="id"/>
<result column="user_id" property="user_id"/>
<result column="title" property="title"/>
<result column="summary" property="summary"/>
<result column="read_count" property="read_count"/>
<result column="create_time" property="create_time"/>
<result column="update_time" property="update_time"/>
</resultMap>
</mapper>
@Select("""
select * from article where id = #{article_Id}
""")
@ResultMap("ActionBaseMapper") //引用资源文件的id
ArticlePo selectMappersXmlById(Integer article_Id);
使用（SqlProvider）提供者操作
1. 新建一个提供者， 对应操作sql静态函数
package com.example.alee.mybatis.springmybatis.provider;
public class SqlProvider {
public static String selectArticle() {
return "select * from article where id=#{id}";
}
public static String updateArticleTime() {
return "update article set update_time=#{newTime} where id=#{id}";
}
public static String insertArticle() {
return """
INSERT INTO article (user_id, title, summary, read_count, create_time, update_time)
VALUES
(#{user_id},#{title},#{summary},#{read_count},#{create_time},#{update_time})
""";
}
public static String deleteArticleById() {
return "DELETE from article where id = #{id}";
}
}
2. 接口查询类 ArticleRepository
public interface ArticleRepository {
//使用提供者查询
@SelectProvider(type = SqlProvider.class, method = "selectArticle")
ArticlePo selectByPrimary(Integer id);
//提供者进行修改
@SelectProvider(type = SqlProvider.class, method = "updateArticleTime")
int updateTimePrimary(LocalDateTime newTime, Integer id);
@InsertProvider(type = SqlProvider.class, method = "insertArticle")
int insertArticle(ArticlePo articlePo);
@DeleteProvider(type = SqlProvider.class, method = "deleteArticleById")
int deleteArticleById(Integer id);
}
3. Spring Test 查询操作
@SpringBootTest
public class RepositoryTest {
@Autowired(required = false)
private ArticleRepository articleRepository;
@Test
void testSelectProvider() {
ArticlePo articlePo = articleRepository.selectByPrimary(1);
System.out.println("articlePo = " + articlePo);
}
@Test
void testUpdateTimePrimary() {
int result = articleRepository.updateTimePrimary(LocalDateTime.now(), 5);
System.out.println("result = " + result);
}
@Test
void testInsertArticle() {
ArticlePo articlePo = new ArticlePo();
articlePo.setUser_id(0125);
articlePo.setTitle("Spring Boot xxx");
articlePo.setSummary("核心讲解，难点剖析，源码分析");
articlePo.setRead_count(15);
articlePo.setCreate_time(LocalDateTime.now());
articlePo.setUpdate_time(LocalDateTime.now());
int result = articleRepository.insertArticle(articlePo);
System.out.println("result = " + result);
}
@Test
void testDeleteArticleById() {
int result = articleRepository.deleteArticleById(7);
System.out.println("result = " + result);
}
}
End。
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