mybatis入门

Bertha 。 2022-05-16 02:12 204阅读 0赞

1.导入jar包  
![这里写图片描述][70]  
2.创建实体类

public class Users { 
        private int id;
        private String name;
        private String sex;
    
    
        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 getSex() {
            return sex;
        }
    
        public void setSex(String sex) {
            this.sex = sex;
        }
    
        public Users() {
            super();
        }
    
        @Override
        public String toString() {
            return "Users [id=" + id + ", name=" + name + ", sex=" + sex + "]";
        }
    }

3.配置mybatis-config.xml文件

<?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "mybatis-3-config.dtd" >
    <configuration>
        <environments default="development">
            <environment id="development">
                <transactionManager type="JDBC"></transactionManager>
                <dataSource type="POOLED">
                    <property name="driver" value="com.mysql.cj.jdbc.Driver" />
                    <property name="url" value="jdbc:mysql://localhost:3306/user?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=UTC&allowMultiQueries=true" />
                    <property name="username" value="root" />
                    <property name="password" value="123456" />
                </dataSource>
            </environment>
        </environments>
        
        <mappers>
            <mapper resource="entity/usersMapper.xml" />
        </mappers>
    </configuration>

4.配置映射文件

<?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "mybatis-3-mapper.dtd" >
    <mapper namespace="entity.usersMapper">
        <select id="queryUsers" parameterType="int" resultType="entity.Users">
    
            select * from users where id=#{id}
    
        </select>
    </mapper>

5.写一个MybatisUtil的工具类

public class MyBatisUtil {
        public static SqlSession openSession() {
            String resource = "mybatis-config.xml";
            SqlSessionFactory sqlSessionFactory = null;
            InputStream inputStream;
            SqlSession session = null;
            try {
                inputStream = Resources.getResourceAsStream(resource);
                sqlSessionFactory = new SqlSessionFactoryBuilder()
                        .build(inputStream);
                session = sqlSessionFactory.openSession();
            } catch (IOException e) {
    
                e.printStackTrace();
            }
    
            return session;
        }
    }

6.在创建一个测试类，这里用的单元测试，需要导入Juint这个jar

public class Text {
      @Test
      public void queryUser(){
          SqlSession session=MyBatisUtil.openSession();
         Users users= session.selectOne("entity.usersMapper.queryUsers", 5);
         System.out.println(users);
      }
    }

7.项目结构图  
![这里写图片描述][70 1]

[70]: /images/20220516/a51dc5dcb9e54fe69af58d2d105e0732.png
[70 1]: /images/20220516/1c57939e62a24cbe9eb8a92cadd76bf8.png