关于MyBatis的一些知识

古城微笑少年丶 2024-03-26 11:04 66阅读 0赞

## MyBatis快速入门 ##

Mybatis是一款优秀的持久层框架，用于简化IDBC开发。

**持久层：**

1、负责将数据保存到数据库的那一层代码

2、JavaEE三层架构：表现层、业务层、持久层

**框架：**

1、框架就是一个半成品软件，是一套可重复利用的、通用的、软件基础代码模型

2、在框架的基础之上构建软件编写更加高效、规范、通用、可扩展

**案例：**查询user表中的所有数据

1、创建user表，并添加数据

2、创建模块，导入坐标

3、编写MyBatis核心配置文件，替换连接信息，解决硬编码问题

4、编写SQL映射文件，统一管理SQL语句，解决硬编码问题

5、编码：1、定义POJO类

2、 加载核心配置文件，获取SQLSessionFactory对象

3、获取SQLSession对象，执行SQL语句

4、释放资源

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**在项目的pom.xml中添加一些依赖：**

<?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>org.example</groupId>
        <artifactId>mybatis-demo</artifactId>
        <version>1.0-SNAPSHOT</version>
    
        <properties>
            <maven.compiler.source>17</maven.compiler.source>
            <maven.compiler.target>17</maven.compiler.target>
        </properties>
    
        <dependencies>
    
            <dependency>
                <groupId>org.mybatis</groupId>
                <artifactId>mybatis</artifactId>
                <version>3.5.5</version>
            </dependency>
    
            
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>5.1.32</version>
            </dependency>
    
    
            <dependency>
                <groupId>junit</groupId>
                <artifactId>junit</artifactId>
                <version>4.13</version>
    
                <scope>test</scope>
            </dependency>
            
            
            <dependency>
                <groupId>org.slf4j</groupId>
                <artifactId>slf4j-api</artifactId>
                <version>1.7.20</version>
            </dependency>
            
            <dependency>
                <groupId>ch.qos.logback</groupId>
                <artifactId>logback-classic</artifactId>
                <version>1.2.3</version>
            </dependency>
            
            <dependency>
                <groupId>ch.qos.logback</groupId>
                <artifactId>logback-core</artifactId>
                <version>1.2.3</version>
            </dependency>
            
        </dependencies>
    
    </project>

**在resource中新建XML文件，名字为mybatis-config.xml：**

<?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>
        
    
        <typeAliases>
            <package name="com.tiheima.pojo"/>
        </typeAliases>
        
        <environments default="development">
            <environment id="development">
                <transactionManager type="JDBC"/>
                <dataSource type="POOLED">
    
                    <property name="driver" value="com.mysql.jdbc.Driver"/>
    
                    <property name="url" value="jdbc:mysql:///mybatis?useSSL=false"/>
                    <property name="username" value="root"/>
                    <property name="password" value="123456"/>
                </dataSource>
            </environment>
        </environments>
        <mappers>
    
    
    
            <package name="com.tiheima.mapper"/>
        </mappers>
    </configuration>

## ![cc877518769f4c5b9cb3860cae0ec42a.png][] ##

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[4aea7dd96c3f42e7b9d7cb69e6c5a4e6.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/26/406e01e7ee2f48eeb80aa465b7490fd3.png
[b4331be98f2e4fd0ad30cee2a73f6a36.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/26/b2fb9aa65bb54a6cb17196443985e561.png
[cc877518769f4c5b9cb3860cae0ec42a.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/26/3c285f955da342ef9e498898b58e87f6.png
[a5dca7845f0f43a9b24c48ccdf1bc74a.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/26/cf2b653f86c541a0aa893ad9641c8e67.png
[fff956c5a05a4da4adbd8535a6236162.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/26/c1b1b40aff434b149a2adbd5959fb76d.png
[d7854479d8dd4dca8a7a74b7c5ac89e4.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/26/773c3b4b0aa14352b8efdae2c37174da.png