MyBatis官方入门实例十步走

ゞ浴缸里的玫瑰 2021-07-24 14:52 311阅读 0赞

**目录**

一 数据库

二 pom文件

三 创建工具类，用来获得sqlSession

四 Mybatis核心配置文件配置

五 实体类

六 mapper类

七 mapper的XML配置

八  测试

九 测试结果

十 官方文档参考

--------------------

# 一 数据库 #

CREATE TABLE `user` (
      `id` int(11) DEFAULT NULL,
      `name` varchar(255) DEFAULT NULL,
      `pwd` varchar(255) DEFAULT NULL
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8;

# 二 pom文件 #

<?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.cakin</groupId>
        <artifactId>mybatisDemo</artifactId>
        <packaging>pom</packaging>
        <version>1.0-SNAPSHOT</version>
        <modules>
            <module>mybatis-01</module>
        </modules>
        
        <dependencies>
            
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>5.1.46</version>
            </dependency>
            
            <dependency>
                <groupId>org.mybatis</groupId>
                <artifactId>mybatis</artifactId>
                <version>3.5.2</version>
            </dependency>
            
            <dependency>
                <groupId>junit</groupId>
                <artifactId>junit</artifactId>
                <version>4.12</version>
            </dependency>
        </dependencies>
        
        <build>
            <resources>
                <resource>
                    <directory>src/main/resources</directory>
                    <includes>
                        <include>**/*.properties</include>
                        <include>**/*.xml</include>
                    </includes>
                    <filtering>true</filtering>
                </resource>
                
                <resource>
                    <directory>src/main/java</directory>
                    <includes>
                        <include>**/*.properties</include>
                        <include>**/*.xml</include>
                    </includes>
                    <filtering>true</filtering>
                </resource>
            </resources>
        </build>
    </project>

# 三 创建工具类，用来获得sqlSession #

package com.cakin.utils;
    
    
    import org.apache.ibatis.session.SqlSession;
    import org.apache.ibatis.session.SqlSessionFactory;
    import org.apache.ibatis.io.Resources;
    import org.apache.ibatis.session.SqlSessionFactoryBuilder;
    
    
    import java.io.InputStream;
    
    
    /**
    * @ClassName: Mybatisutil
    * @Description: Mybatis工具类
    * @Date: 2020/6/12
    * @Author: cakin
    */
    // sqlSessionFactory-->sqlSession
    public class MybatisUtil {
        private static SqlSessionFactory sqlSessionFactory;
    
    
        static {
            try {
                // 使用Mybatis第一步：获取sqlSessionFactory对象
                String resource = "mybatis-config.xml";
                InputStream inputStream = Resources.getResourceAsStream(resource);
                sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    
    
        // 从sqlSessionFactory获取sqlSession
        public static SqlSession getSqlSession(){
            return sqlSessionFactory.openSession();
        }
    }

# 四 Mybatis核心配置文件配置 #

<?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.jdbc.Driver"/>
                    
                    <property name="url" value="jdbc:mysql://localhost:3306/mybatis?useUnicode=true&characterEncoding=utf8&useSSL=true"/>
                    <property name="username" value="root"/>
                    <property name="password" value="123456"/>
                </dataSource>
            </environment>
        </environments>
        
        <mappers>
            <mapper resource="com/cakin/mapper/UserMapper.xml"></mapper>
        </mappers>
    </configuration>

# 五 实体类 #

package com.cakin.pojo;
    
    
    /**
    * @ClassName: User
    * @Description: User实体类
    * @Date: 2020/6/12
    * @Author: cakin
    */
    public class User {
        private int id;
        private String name;
        private String pwd;;
    
    
        public User() {
        }
    
    
        public User(int id, String name, String pwd) {
            this.id = id;
            this.name = name;
            this.pwd = pwd;
        }
    
    
        public int getId() {
            return id;
        }
    
    
        public void setId(int id) {
            this.id = id;
        }
    
    
        public String getName() {
            return name;
        }
    
    
        public void setName(String name) {
            this.name = name;
        }
    
    
        public String getPwd() {
            return pwd;
        }
    
    
        public void setPwd(String pwd) {
            this.pwd = pwd;
        }
    
    
        @Override
        public String toString() {
            return "User{" +
                    "id=" + id +
                    ", name='" + name + '\'' +
                    ", pwd='" + pwd + '\'' +
                    '}';
        }
    }

# 六 mapper类 #

package com.cakin.mapper;
    
    
    import com.cakin.pojo.User;
    
    
    import java.util.List;
    
    
    public interface UserMapper {
        List<User> getUserList();
    }

# 七 mapper的XML配置 #

<?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.cakin.mapper.UserMapper">
        <select id="getUserList" resultType="com.cakin.pojo.User">
            select * from user
        </select>
    </mapper>

# 八  测试 #

package com.cakin.mapper;
    
    
    import com.cakin.pojo.User;
    import com.cakin.utils.MybatisUtil;
    import org.apache.ibatis.session.SqlSession;
    import org.junit.Test;
    
    
    import java.util.List;
    
    
    /**
    * @ClassName: UserDaoTest
    * @Description: 测试类
    * @Date: 2020/6/12
    * @Author: cakin
    */
    public class UserDaoTest {
        @Test
        public void test(){
            // 第一步，获得sqlSession
            SqlSession sqlSession = MybatisUtil.getSqlSession();
            // 执行SQL
            UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
            List<User> userList = userMapper.getUserList();
            for (User user : userList) {
                System.out.println(user);
            }
            // 关闭session
            sqlSession.close();
        }
    }

# 九 测试结果 #

User{id=1, name='cakin', pwd='12345'}
    User{id=2, name='cakin24', pwd='123456'}

# 十 官方文档参考 #

[https://mybatis.org/mybatis-3/zh/getting-started.html][https_mybatis.org_mybatis-3_zh_getting-started.html]

[https_mybatis.org_mybatis-3_zh_getting-started.html]: https://mybatis.org/mybatis-3/zh/getting-started.html