2023/8/14 Java EE复习（mybatis-1搭建方法）

1、在maven模块的pom.xml中添加mybatis依赖

maven模块的创建流程见
https://blog.youkuaiyun.com/qq_52800655/article/details/132282432

<properties>
	<!-- Mybatis -->
    <mybatis.version>3.2.8</mybatis.version>
    <mybatis.spring.version>1.2.2</mybatis.spring.version>
	<!-- 连接池 -->
    <c3p0-version>0.9.1.2</c3p0-version>
    <!-- 日志处理 -->
    <slf4j.version>1.6.4</slf4j.version>
</properties>
<dependencies>
	<!-- Mybatis -->
    <dependency>
        <groupId>org.mybatis</groupId>
        <artifactId>mybatis</artifactId>
        <version>${mybatis.version}</version>
    </dependency>
    <dependency>
        <groupId>org.mybatis</groupId>
        <artifactId>mybatis-spring</artifactId>
        <version>${mybatis.spring.version}</version>
    </dependency>
    <!-- 连接池? -->
    <!-- connect pool with c3p0 -->
    <dependency>
        <groupId>c3p0</groupId>
        <artifactId>c3p0</artifactId>
        <version>${c3p0-version}</version>
    </dependency>
    <!-- 日志处理 -->
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-log4j12</artifactId>
        <version>${slf4j.version}</version>
    </dependency>   
</dependencies>

2、配置mybatis核心配置文件

<?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>
        <!-- 下划线字段对应实体类驼峰命名 数据库表：banji_id 映射到类里面：banjiId -->
        <setting name="mapUnderscoreToCamelCase" value="true"/>
    </settings>
    <typeAliases>
        <!-- 扫描包里面的类，批量起别名，别名即类名，不区分大小写 -->
        <package name="model"/>
    </typeAliases>
    <environments default="development">
        <environment id="development">
            <!-- 使用JDBC的事物管理 -->
            <transactionManager type="JDBC"/>
            <!-- 配饰数据库连接池 -->
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.cj.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/dataBaseName?useSSL=false&amp;Timzone=UTC&amp;characterEncoding=utf-8"/>
                <property name="username" value="username"/>
                <property name="password" value="password"/>
            </dataSource>
        </environment>
    </environments>
    <!-- 加载映射文件 -->
    <mappers>
    	<!--映射文件路径为：modelName/src/main/resources/mapper/StudentMapper.xml-->
    	<mapper resource="mapper/StudentMapper.xml"/>
    </mappers>
</configuration>

3、model层和映射文件

（1）model层的类

package mybatis.model;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.ToString;

@Data
@AllArgsConstructor
@NoArgsConstructor
@ToString
public class Student {
    private Integer id;
    private String name;
    private Integer age;
    private String gender;
    private Integer banjiId;
}

（2）映射文件

<?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="student">
	<!--批量查找，返回值不需要写List-->
    <select id="selectAll" resultType="Student">
        select *
        from student
    </select>
    <!--修改操作默认返回Integer，不需要resultType-->
</mapper>

4、log4j日志配置文件

文件路径：modelName/src/main/resources/log4j.properties

# Global logging configuration
log4j.rootLogger=DEBUG, stdout
# Console output...
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%5p [%t] - %m%n

5、单元测试展示

@Test
public void selectAll() {
    String resource = "mybatis.xml";
    InputStream inputStream = Resources.getResourceAsStream(resource);
    //sql对话工厂
    SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
    //得到SqlSession
    SqlSession sqlSession = sqlSessionFactory.openSession();
    List<Student> list = sqlSession.selectList("student.selectAll");
    for (Student student : list) {
        System.out.println(student);
    }
    sqlSession.close();
}

测试输出