mybatis入门---[笔记]

mybatis入门

• ​​工作原理​​

• ​​简单的mybatis运用​​

• ​​Mybatis的配置文件详解​​

工作原理

概念什么的不去说了;

简单的mybatis运用

首先三步走:
1,创建maven工程
2,配置依赖
3,功能实现

配置依赖,这里引入mysql ,mybatis,jdbc
junit

<?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.gavin.MybatisDemo</groupId>
    <artifactId>MybatisDemo</artifactId>
    <version>1.0-SNAPSHOT</version>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>1.7</maven.compiler.source>
        <maven.compiler.target>1.7</maven.compiler.target>
    </properties>
    <build>
        <!--        引入资源复制插件-->
        <resources>
            <resource>
                <directory>src/main/java/com/gavin/app</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
            </resource>
            <resource>
                <directory>src/main/resources</directory>
                <includes>
                    <include>**/*.xml</include>
                    <include>**/*.properties</include>
                </includes>
            </resource>
        </resources>
        <!--        引入编译器插件-->
        <plugins>
            <!--JDK编译插件 -->
            <plugin>
                <!--插件坐标 -->
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.2</version>
                <!-- -->
                <configuration>
                    <!-- 源代码使用JDK版本-->
                    <source>16</source>
                    <!-- 源代码编译为class文件的版本，要保持跟上面版本一致-->
                    <target>16</target>
                    <encoding>UTF-8</encoding>
                </configuration>
            </plugin>
            <plugin>

                <groupId>org.apache.tomcat.maven</groupId>
                <artifactId>tomcat7-maven-plugin</artifactId>
                <version>2.2</version>
                <configuration>
                    <!-- 配置Tomcat监听端口 -->
                    <port>8080</port>
                    <!-- 配置项目的访问路径(Application Context) -->
                    <path>/</path>
                </configuration>

            </plugin>


        </plugins>
    </build>
<dependencies>
    <!-- https://mvnrepository.com/artifact/log4j/log4j -->
    <dependency>
        <groupId>log4j</groupId>
        <artifactId>log4j</artifactId>
        <version>1.2.17</version>
    </dependency>


    <!-- https://mvnrepository.com/artifact/org.mybatis/mybatis -->
    <dependency>
        <groupId>org.mybatis</groupId>
        <artifactId>mybatis</artifactId>
        <version>3.5.7</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>8.0.16</version>
    </dependency>

    <!-- https://mvnrepository.com/artifact/com.google.code.gson/gson -->
    <dependency>
        <groupId>com.google.code.gson</groupId>
        <artifactId>gson</artifactId>
        <version>2.8.4</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.apache.taglibs/taglibs-standard-impl -->
    <dependency>
        <groupId>org.apache.taglibs</groupId>
        <artifactId>taglibs-standard-impl</artifactId>
        <version>1.2.5</version>
        <scope>runtime</scope>
    </dependency>

</dependencies>

</project>

接着配置 mybatis核心文件

可以事先准备一个模板,以后就不同那么麻烦了做重复劳动了---->>
以Idea为例

File----->>>settings---->>>Editor---->>File and Code Templates

配置文件中输入的内容---->>>

MybatisConfig.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>
  <environments default="development">
    <environment >
      <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="org/mybatis/example/BlogMapper.xml"/>
  </mappers>
</configuration>

MybatisMapper.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="org.mybatis.example.BlogMapper">
  <select  resultType="Blog">
    select * from Blog where id = #{id}
  </select>
</mapper>

最后做收尾工作----->>

Mybatis的配置文件详解

每个基于 MyBatis 的应用都是以一个 SqlSessionFactory 的实例为核心的。SqlSessionFactory 的实例可以通过 SqlSessionFactoryBuilder 获得。而 SqlSessionFactoryBuilder 则可以从 XML 配置文件或一个预先配置的 Configuration 实例来构建出 SqlSessionFactory 实例。