mybatis_001

最新推荐文章于 2022-08-25 23:22:08 发布

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最新推荐文章于 2022-08-25 23:22:08 发布

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分类专栏： mybatis

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本文介绍了一个使用MyBatis框架进行员工信息查询的示例，包括如何设置数据源、编写SQL映射文件以及使用JUnit进行测试。

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package com.casey.mybatis.bean;

public class Employee {
    private Integer id;
    private String name;
    private String gender;
    private String email;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String lastname) {
        this.name = lastname;
    }

    public String getGender() {
        return gender;
    }

    public void setGender(String gender) {
        this.gender = gender;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    @Override
    public String toString() {
        return "Employee{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", gender='" + gender + '\'' +
                ", email='" + email + '\'' +
                '}';
    }
}



package com.casey.mybatis.test;

import com.casey.mybatis.bean.Employee;
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 org.junit.Test;

import java.io.IOException;
import java.io.InputStream;
/**
* 1.根据xml全局配置文件，创建一个sqlSessionFactory
 *   有数据源一些运行环境信息
 *2.sql映射文件：配置每一个sql,以及sql的封装规则等
 * 3.将sql映射文件映射到全局配置文件中
 * 4.写代码：
 *   1.根据全局配置文件，得到sqlSessionFactory;
 *   2.使用sqlSession工厂得到session对象，使用session对象来进行增删改查
 *   3.一个session代表和数据库的一次对话，使用完后关闭
* */
public class mybatisTest {
    @Test
    public void test() throws IOException {
        String resource = "mybatis.xml";
        InputStream inputStream = Resources.getResourceAsStream(resource);
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
/**
 * 从 SqlSessionFactory 中获取 SqlSession
 * **/
        SqlSession session = sqlSessionFactory.openSession();
try {
    //第一个参数表示sql唯一标识
    //第二个参数表示执行sql要用的重要参数
    Employee employee =  session.selectOne("com.casey.mybatis.EmployeeMapper.selectEmp",1);
    System.out.println(employee);
}finally {
    session.close();
}
    }

}

<maven>

<?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_001_helloword</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <!-- 引入mysql驱动 -->
        <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.17</version>
        </dependency>
        <!-- Junit -->
                <dependency>
                     <groupId>junit</groupId>
                     <artifactId>junit</artifactId>
                     <version>4.12</version>
                 </dependency>
                 <dependency>
                     <groupId>log4j</groupId>
                     <artifactId>log4j</artifactId>
                     <version>1.2.17</version>
                 </dependency>
                 <dependency>
                     <groupId>org.mybatis</groupId>
                     <artifactId>mybatis</artifactId>
                     <version>3.2.6</version>
                 </dependency>
    </dependencies>



</project>

<mybatis.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 id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.cj.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/mybatis?serverTimezone=UTC"/>
                <property name="username" value="root"/>
                <property name="password" value="root"/>
            </dataSource>
        </environment>
    </environments>
<!--    将写好的sql映射文件放入全局配置文件中-->
    <mappers>
        <mapper resource="EmployeeMapper.xml"/>
    </mappers>
</configuration>

<EmployeeMapper.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="com.casey.mybatis.EmployeeMapper">
<!--
namespace:名称空间
id:唯一标识符
resultType：返回的结果集
#{id}：传递过来的参数
-->
    <select id="selectEmp" resultType="com.casey.mybatis.bean.Employee">
    select * from employee where id = #{id}
  </select>
</mapper>