在intelliJ IDEA中搭建mybatis的过程详解-mybatis学习笔记01

墨蓝 2022-04-05 13:42 91阅读 0赞

**在idea中搭建mybatis的过程：**  
**1.1新建lib文件夹，然后导入jar包**  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3N1cHJlemhlbmc_size_16_color_FFFFFF_t_70]  
**1.2将lib文件夹下面的jar包与该项目关联起来**  
![在这里插入图片描述][20181212183525514.png]![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3N1cHJlemhlbmc_size_16_color_FFFFFF_t_70 1]![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3N1cHJlemhlbmc_size_16_color_FFFFFF_t_70 2]![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3N1cHJlemhlbmc_size_16_color_FFFFFF_t_70 3]**这步完成过后就完成了，导入jar包与项目的关联**  
**1.3新建resources文件并将其设置为资源文件夹**  
![在这里插入图片描述][20181212183929489.png]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3N1cHJlemhlbmc_size_16_color_FFFFFF_t_70 4]接下来：  
①先添加一个db.properties文件，用于配置数据库

jdbc.driver=com.mysql.jdbc.Driver
    jdbc.url=jdbc:mysql:///数据库名称
    jdbc.username=登陆数据库用户名
    jdbc.password=登陆数据库密码

②再添加一个mybatis-config.xml文件，用于配置mybatis

<?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 resource="db.properties">
    
        </properties>
    
        
        <environments default="development">
            <environment id="development">
                
                <transactionManager type="JDBC"/>
                
                <dataSource type="POOLED">
    
                    <property name="driver" value="${jdbc.driver}"/>
                    <property name="url" value="${jdbc.url}"/>
                    <property name="username" value="${jdbc.username}"/>
                    <property name="password" value="${jdbc.password}"/>
    
                </dataSource>
            </environment>
        </environments>
    
        <mappers>
            
            <mapper resource="cn/mesmile/mybatis/domain/UserMapper.xml"/>
        </mappers>
    
    </configuration>

**1.4新建domain层，在此包下建立实体类**

package cn.mesmile.mybatis.domain;
    
    /**
     * @Created with IDEA
     * @author: Super Zheng
     * @Description: 这是数据库中对应表的实体类
     * @Date:2018/12/12
     * @Time:16:49
     */
    public class User {
        private Long id;
        private String username;
        private String password;
    
        public Long getId() {
            return id;
        }
    
        public void setId(Long 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;
        }
    
        @Override
        public String toString() {
            return "User{" +
                    "id=" + id +
                    ", username='" + username + '\'' +
                    ", password='" + password + '\'' +
                    '}';
        }
    }

**1.5新建dao层在此包下新建接口类**

package cn.mesmile.mybatis.dao;
    
    import cn.mesmile.mybatis.domain.User;
    
    import java.util.List;
    
    /**
     * @Created with IDEA
     * @author: Super Zheng
     * @Description: java类作用描述
     * @Date:2018/12/12
     * @Time:16:51
     */
    public interface IUserDao {
        // 保存用户
        void save(User user);
        // 删除用户
        void delete(Long id);
        // 修改用户
        void update(User user);
        // 查询一个用户
        User findOne(Long id);
        // 查询所有用户
        List<User> findAll();
    }

**1.6自定义工具类，用于获得SqlSession对象**

package cn.mesmile.mybatis.util;
    
    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 java.io.IOException;
    import java.io.Reader;
    
    /**
     * @Created with IDEA
     * @author: Super Zheng
     * @Description: 这是自定义的工具类
     * @Date:2018/12/12
     * @Time:16:54
     */
    public class MybatisUtil {
    
        private static  SqlSessionFactory sqlSessionFactory = null;
    
        static {
            // 通过配置文件获取到reader
            Reader reader = null;
            try {
                reader = Resources.getResourceAsReader("mybatis-config.xml");
                // 得到一个SqlSessionFactory
                sqlSessionFactory= new SqlSessionFactoryBuilder().build(reader);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    
        // 获得SqlSession对象
        public static SqlSession getSqlSession(){
            return sqlSessionFactory.openSession();
        }
    }

**1.7新建dao层的实现包，在实现包下建立实现类**

package cn.mesmile.mybatis.dao.impl;
    
    import cn.mesmile.mybatis.dao.IUserDao;
    import cn.mesmile.mybatis.domain.User;
    import cn.mesmile.mybatis.util.MybatisUtil;
    import org.apache.ibatis.session.SqlSession;
    
    import java.util.List;
    
    /**
     * @Created with IDEA
     * @author: Super Zheng
     * @Description: 这个类是实现了IUserDao接口
     * @Date:2018/12/12
     * @Time:16:54
     */
    public class UserDaoImpl implements IUserDao {
    
        // 注意这里的字符串内容是：UserMapper.xml中的 namespace的值，注意这里最后加了一个小点 .
        private static String NAMESPACE="cn.mesmile.mybatis.domain.UserMapper.";
    
        @Override
        public void save(User user) {
    
            SqlSession sqlSession=null;
            try {
                // 调用工具类，获得sqlSession对象
                sqlSession = MybatisUtil.getSqlSession();
                // 调用方法保存，参数1：为 UserMapper.xml中的namespace+对应的id值，参数2：传入的参数
                sqlSession.insert(NAMESPACE + "save", user);
                // 提交事务
                sqlSession.commit();
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                if (sqlSession != null) {
                    // 关闭SQLSession对象
                    sqlSession.close();
                }
            }
        }
    
        @Override
        public void delete(Long id) {
            SqlSession sqlSession=null;
            try {
                // 调用工具类，获得sqlSession对象
                sqlSession = MybatisUtil.getSqlSession();
                // 调用方法保存，参数1：为 UserMapper.xml中的namespace+对应的id值，参数2：传入的参数
                sqlSession.delete(NAMESPACE + "delete", id);
                // 提交事务
                sqlSession.commit();
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                if (sqlSession != null) {
                    // 关闭SQLSession对象
                    sqlSession.close();
                }
            }
    
        }
    
        @Override
        public void update(User user) {
            SqlSession sqlSession=null;
            try {
                // 调用工具类，获得sqlSession对象
                sqlSession = MybatisUtil.getSqlSession();
                // 调用方法保存，参数1：为 UserMapper.xml中的namespace+对应的id值，参数2：传入的参数
                sqlSession.update(NAMESPACE + "update", user);
                // 提交事务
                sqlSession.commit();
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                if (sqlSession != null) {
                    // 关闭SQLSession对象
                    sqlSession.close();
                }
            }
    
        }
    
        @Override
        public User findOne(Long id) {
            SqlSession sqlSession=null;
            try {
                // 调用工具类，获得sqlSession对象
                sqlSession = MybatisUtil.getSqlSession();
                // 调用方法保存，参数1：为 UserMapper.xml中的namespace+对应的id值，参数2：传入的参数
                return sqlSession.selectOne(NAMESPACE + "findOne", id);
    
            } catch (Exception e) {
                e.printStackTrace();
                return null;
            } finally {
                if (sqlSession != null) {
                    // 关闭SQLSession对象
                    sqlSession.close();
                }
            }
        }
    
        @Override
        public List<User> findAll() {
    
            SqlSession sqlSession=null;
            try {
                // 调用工具类，获得sqlSession对象
                sqlSession = MybatisUtil.getSqlSession();
                // 调用方法保存，参数1：为 UserMapper.xml中的namespace+对应的id值
                return sqlSession.selectList(NAMESPACE + "findAll");
    
            } catch (Exception e) {
                e.printStackTrace();
                return null;
            } finally {
                if (sqlSession != null) {
                    // 关闭SQLSession对象
                    sqlSession.close();
                }
            }
        }
    }

**1.8在domain层下面新建配置文件domianMapper.xml 在本例中名称为：UserMapper.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="cn.mesmile.mybatis.domain.UserMapper">
    
        
        <select id="findOne" parameterType="long" resultType="cn.mesmile.mybatis.domain.User">
            select * from user where id = #{id}
        </select>
    
        
        <select id="findAll" parameterType="long" resultType="cn.mesmile.mybatis.domain.User">
            select * from user
        </select>
    
        
        <insert id="save" parameterType="cn.mesmile.mybatis.domain.User">
            insert into  user (username,password) VALUES (#{username},#{password})
        </insert>
    
        
        <delete id="delete" parameterType="long">
            delete from user where id = #{id}
        </delete>
    
        
        <update id="update" parameterType="cn.mesmile.mybatis.domain.User">
            update user set username=#{username},password=#{password} where id=#{id}
        </update>
    
    </mapper>

**1.9一次性生成测试类，然后测试，选中dao层下面的接口**  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3N1cHJlemhlbmc_size_16_color_FFFFFF_t_70 5]![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3N1cHJlemhlbmc_size_16_color_FFFFFF_t_70 6]**2.0测试结果**  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3N1cHJlemhlbmc_size_16_color_FFFFFF_t_70 7]

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[20181212183525514.png]: https://img-blog.csdnimg.cn/20181212183525514.png
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[20181212183929489.png]: /images/20220405/7dd3b6511c004ca68f962b2bfb8735f2.png
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