Mybatis源码解析之环境搭建

项目相继都停了，导致最近比较清闲，遂准备学习Mybatis源码，学习源码首先要先会使用，故搭建个demo。

该demo不考虑其他东西，只使用Mybatis,使用maven构建，Mysql数据库。

pom.xml依赖的包:

<dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.2.8</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.27</version>
        </dependency>

另配置过程中，出现一个问题，找不到can not found resourse com/logistics/mapper/UserMapper.xml

<mappers>
    <mapper resource="com/logistics/mapper/UserMapper.xml"/>
</mappers>

build标签 加入下面代码

<build>
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
            </resource>
        </resources>
    </build>

配置的mybatis配置文件如下：

<?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>-->
        <!--<property name="dialect" value="mysql"/>-->
    <!--</properties>-->

    <properties resource="jdbc.properties"></properties>


    <settings>
        <!-- 使全局的映射器启用或禁用缓存。 -->
        <setting name="cacheEnabled" value="true"/>
        <!-- 全局启用或禁用延迟加载。当禁用时，所有关联对象都会即时加载。 -->
        <setting name="lazyLoadingEnabled" value="true"/>
        <!-- 当启用时，有延迟加载属性的对象在被调用时将会完全加载任意属性。否则，每种属性将会按需要加载。 -->
        <setting name="aggressiveLazyLoading" value="false"/>
        <!-- 允许JDBC支持生成的键。 -->
        <setting name="useGeneratedKeys" value="false"/>
    </settings>

    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <!-- 配置数据库连接信息 -->
            <dataSource type="POOLED">
                <property name="driver" value="${jdbc.driverClassName}"/>
                <property name="url" value="${jdbc.url}"/>
                <property name="username" value="${jdbc.username}"/>
                <property name="password" value="${jdbc.password}"/>
            </dataSource>
        </environment>
    </environments>

    <mappers>
        <mapper resource="com/logistics/mapper/UserMapper.xml"/>
    </mappers>

</configuration>

jdbc配置文件：

jdbc.driverClassName=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/logistics
jdbc.username=root
jdbc.password=123456

接口：

public interface UserMapper {

    UserVO getUserById(String userId);
}

接口对应的XML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="com.logistics.mapper.UserMapper">

    <select id="getUserById" parameterType="java.lang.String" resultType="com.logistics.base.vo.UserVO"
            flushCache="true">
        SELECT u.id,u.username,u.password,u.phone,u.email,u.`status` FROM userinfo u WHERE u.id = #{id}
    </select>
</mapper>

建立User对象：

package com.logistics.base.po;

/**
 * Created by dell on 2017-07-03.
 */
public class UserVO {

    private String id;
    private String username;
    private String password;
    private String phone;
    private String email;
    private String status;

    public String getId() {
        return id;
    }

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

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getPhone() {
        return phone;
    }

    public void setPhone(String phone) {
        this.phone = phone;
    }

    public String getEmail() {
        return email;
    }

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

    public String getStatus() {
        return status;
    }

    public void setStatus(String status) {
        this.status = status;
    }
}

建立数据库：

测试类：

public class UserTest {
    @Test
    public void test_0() {
        String mybatis = "mybatis-config.xml";
        try {
            Reader reader = Resources.getResourceAsReader(mybatis);
            SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(reader);
            SqlSession session = factory.openSession();

            UserVO userVO = session.selectOne("com.logistics.mapper.UserMapper.getUserById", "C-0002");
            System.out.println(userVO.getUsername());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

开始运行测试方法。

这张图是项目总图：