Mybatis从入门到精通——Mybatis快速使用（3）

古城微笑少年丶 2023-07-12 09:26 125阅读 0赞

# 一、准备工作 #

## 1.maven依赖 ##

<dependencies>
            
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>8.0.18</version>
            </dependency>
    
            
            <dependency>
                <groupId>junit</groupId>
                <artifactId>junit</artifactId>
                <version>4.12</version>
            </dependency>
    
            
            <dependency>
                <groupId>org.mybatis</groupId>
                <artifactId>mybatis</artifactId>
                <version>3.5.4</version>
            </dependency>
    
    
            
            <dependency>
                <groupId>org.slf4j</groupId>
                <artifactId>slf4j-api</artifactId>
                <version>1.7.10</version>
            </dependency>
            <dependency>
                <groupId>ch.qos.logback</groupId>
                <artifactId>logback-classic</artifactId>
                <version>1.1.2</version>
            </dependency>
            <dependency>
                <groupId>ch.qos.logback</groupId>
                <artifactId>logback-core</artifactId>
                <version>1.1.2</version>
            </dependency>
            
        </dependencies>

## 2.实体类 ##

public class Person {
    
        private Integer id;
    
        private String name;
    
        private String sex;
    
        private String telephone;
    
        private String address;
    
        private Integer age;
    
        public Integer getId() {
            return id;
        }
    
        public void setId(Integer 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 String getTelephone() {
            return telephone;
        }
    
        public void setTelephone(String telephone) {
            this.telephone = telephone;
        }
    
        public String getAddress() {
            return address;
        }
    
        public void setAddress(String address) {
            this.address = address;
        }
    
        public Integer getAge() {
            return age;
        }
    
        public void setAge(Integer age) {
            this.age = age;
        }
    
        @Override
        public String toString() {
            return "Person{" +
                    "id=" + id +
                    ", name='" + name + '\'' +
                    ", sex='" + sex + '\'' +
                    ", telephone='" + telephone + '\'' +
                    ", address='" + address + '\'' +
                    ", age=" + age +
                    '}';
        }
    }

### 3.SQL资源 ###

DROP TABLE IF EXISTS `person`;
    CREATE TABLE `person` (
      `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
      `name` varchar(30) NOT NULL COMMENT '名字',
      `sex` char(1) NOT NULL DEFAULT '男' COMMENT '性别',
      `telephone` varchar(11) DEFAULT NULL COMMENT '手机号',
      `address` varchar(50) DEFAULT NULL COMMENT '地址',
      `age` tinyint(4) DEFAULT NULL COMMENT '年龄',
      PRIMARY KEY (`id`)
    ) ENGINE=InnoDB AUTO_INCREMENT=1295453 DEFAULT CHARSET=utf8;
     
     
    INSERT INTO `person` VALUES ('1', 'xy', '男', '123456', '测试', '18');
    INSERT INTO `person` VALUES ('2', 'ceshi', '女', '123456789', '美国', '20');
    INSERT INTO `person` VALUES ('3', 'ceshi', '女', '123456789', '美国', '21');

# 二、Mybatis使用步骤 #

## 1.创建配置文件mybatis-config.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>
    
        <settings>
            
            <setting name="lazyLoadTriggerMethods"  value=""/>
                <setting name="logImpl" value="SLF4J"/>
        </settings>
    
        
        <environments default="mysql">
            <environment id="mysql">
                
                <transactionManager type="JDBC"></transactionManager>
                
                <dataSource type="POOLED">
                    <property name="driver" value="com.mysql.cj.jdbc.Driver"></property>
                    <property name="url" value="jdbc:mysql://localhost:3306/mybatis_study?serverTimezone=GMT%2B8"></property>
                    <property name="username" value="root"></property>
                    <property name="password" value="123456"></property>
                </dataSource>
            </environment>
        </environments>
    
        
        <mappers>
            <mapper resource="mappers/PersonMapper.xml"></mapper>
        </mappers>
        
    </configuration>

## 2.创建mapper接口 ##

public interface PersonMapper {
    
        Person selectById(Integer id);
    }

## 3.创建mapper.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.my.mapper.PersonMapper">
        
        <select id="selectById" parameterType="int" resultType="com.my.entity.Person">
            select * from person where id = #{id}
        </select>
    
    </mapper>

## 4.创建测试类 ##

public class MybatisTest {
    
        private SqlSessionFactory sqlSessionFactory;
    
        @Before
        public void init() throws IOException {
            String resource = "mybatis-config.xml";
            //1.使用mybatis的工具读取配置文件
            InputStream inputStream = Resources.getResourceAsStream(resource);
            SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();
            //2.创建sqlSessionFactory
            sqlSessionFactory = sqlSessionFactoryBuilder.build(inputStream);
            inputStream.close();
        }
    
        @Test
        public void test() {
            //3.获取sqlSession
            SqlSession sqlSession = sqlSessionFactory.openSession();
            //4.获取mapper接口实现类
            PersonMapper personMapper = sqlSession.getMapper(PersonMapper.class);
            //5.调用方法
            Person person = personMapper.selectById(1);
            System.out.println(person);
            //6.释放资源
            sqlSession.close();
        }
    }

## 5.目录结构 ##

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