0. mysql navicate链接分享
链接：https://pan.baidu.com/s/1U9yWY5ENZXhOE9F9wC7ZvA?pwd=1111
提取码：1111
链接：https://pan.baidu.com/s/15yO3dYreuOjZ1RvrNql7gw?pwd=1111
提取码：1111
1. mvn坐标引入
mvn公共中心仓地址：https://mvnrepository.com/
输入jdbc找一个适当的版本
输入mysql找一个适当的版本
添加搭配mvn的 dependentcies
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.msb</groupId>
<artifactId>TestMyBatis01</artifactId>
<version>1.0-SNAPSHOT</version>
<dependencies>
<!-- https://mvnrepository.com/artifact/org.mybatis.spring.boot/mybatis-spring-boot-starter -->
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>2.2.2</version>
</dependency>
<!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.28</version>
</dependency>
</dependencies>
</project>
2. mysql的核心配置文件
搜索 mybatis中文网 https://mybatis.net.cn/getting-started.html
点击 入门
resource下面新建 mybatis.xml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>
<environments default="mysql">
<environment id="mysql">
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<property name="driver" value="com.mysql.cj.jdbc.Driver"/>
<!-- 1. mysql是数据库的名字 -->
<!-- & 是&符的转义符-->
<property name="url" value="jdbc:mysql://127.0.0.1:3306/mysql?useSSL=false&useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai&allowPublicKeyRetrieval=true"/>
<property name="username" value="root"/>
<property name="password" value="root"/>
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="mapper/BookMapper.xml"/>
</mappers>
</configuration>
创建Book实体类
package com.msb.pojo;
/**
* @Auther: jack.chen
* @Date: 2023/11/8 - 11 - 08 - 23:22
* @Description: com.msb.pojo
* @version: 1.0
*/
public class Book {
private int id;
private String name;
private String author;
private Double price;
public Book() {
}
public Book(int id, String name, String author, Double price) {
this.id = id;
this.name = name;
this.author = author;
this.price = price;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getAuthor() {
return author;
}
public void setAuthor(String author) {
this.author = author;
}
public Double getPrice() {
return price;
}
public void setPrice(Double price) {
this.price = price;
}
@Override
public String toString() {
return "Book{" +
"id=" + id +
", name='" + name + '\'' +
", author='" + author + '\'' +
", price=" + price +
'}';
}
}
创建mapper
<?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="a.b.c">
<select id="selectAllBooks" resultType="com.msb.pojo.Book">
select * from t_book
</select>
</mapper>
创建Test类
import com.msb.pojo.Book;
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 java.io.IOException;
import java.io.InputStream;
import java.util.List;
/**
* @Auther: jack.chen
* @Date: 2023/11/8 - 11 - 08 - 23:31
* @Description: PACKAGE_NAME
* @version: 1.0
*/
public class TestBook {
public static void main(String[] args) throws IOException {
String resource = "mybatis.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
SqlSession sqlSession = sqlSessionFactory.openSession();
List<Object> objects = sqlSession.selectList("a.b.c.selectAllBooks");
for (Object object : objects) {
Book b = (Book) object;
System.out.println(b);
}
sqlSession.close();
inputStream.close();
}
}
运行
则说明查找ok
注意下 名称空间 a.b.c selectAllBooks可能有重名 所以 加上名称空间 a.b.c区分
3. 返回值类型 别名
BookMapper.xml里面定义了 返回值的类型 resultType
可以对这个resultType 取别名
- mybatis.xml里面配置
注意规范要求一定要放在environments 这个标签之前
命名为bbbb
mapper.xml里面也定义成 bbbb
4. 将数据的配置提取配置文件
新建 db.properties
url=jdbc:mysql://127.0.0.1:3306/mysql?useSSL=false&useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai&allowPublicKeyRetrieval=true
driver=com.mysql.cj.jdbc.Driver
username=root
password=root
注意 url里面没有转义符
mybatis.xml里面修改基本配置
<?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>
<properties resource="db.properties"></properties>
<typeAliases>
<typeAlias type="com.msb.pojo.Book" alias="bbbb"></typeAlias>
</typeAliases>
<environments default="mysql">
<environment id="mysql">
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<property name="driver" value="${driver}"/>
<property name="url" value="${url}"/>
<property name="username" value="${username}"/>
<property name="password" value="${password}"/>
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="mapper/BookMapper.xml"/>
</mappers>
</configuration>
4. log4j修改日志输出
添加依赖
<!-- https://mvnrepository.com/artifact/log4j/log4j -->
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.17</version>
</dependency>
log4j.rootLogger = DEBUG , console
log4j.logger.a.b.c = TRACE
log4j.appender.console = org.apache.log4j.ConsoleAppender
log4j.appender.console.Target = System.out
log4j.appender.console.layout = org.apache.log4j.PatternLayout
log4j.appender.console.layout.ConversionPattern = [%p] [%-d{yyy-MM-dd HH\:mm\:ss}] %C.%M(%L) | %m%n