学习日常-Mybatis之使用注解开发

数据库

第一步：使用IDEA新建实体类

package Com.fvti.Myabtis.Account;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@AllArgsConstructor
@NoArgsConstructor
public class Person {
    private Integer id;
    private String username;
    private String password;
    private String gender;

}

第二步：创建Mapper接口

package Com.fvti.Myabtis.Dao;

import Com.fvti.Myabtis.Account.Person;
import org.apache.ibatis.annotations.Select;
import org.w3c.dom.ls.LSInput;

import java.util.List;

public interface PersonMapper {


    @Select("select  * from test.user")
    List<Person> findAllPerson();
}

第三步：修改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>
    <!--引入外部文件-->
    <properties resource="db.properties"/>

    <!---->
    <settings>
        <setting name="logImpl" value="Log4j"/>
        <!--配置全局默认缓存-->
        <setting name="cacheEnabled" value="true"/>
    </settings>

    <!--设置别名-->
   <!-- <typeAliases>
        <typeAlias type="Com.MyStudy.Bean.User" alias="user"></typeAlias>
        <typeAlias type="Com.MyStudy.Bean.Bboss" alias="boss"></typeAlias>
    </typeAliases>-->

    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="POOLED">
                <property name="driver" value="${driver}"/>
                <property name="url" value="${url}"/>
                <property name="username" value="${username}"/>
                <property name="password" value="${password}"/>

            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper class="Com.fvti.Myabtis.Dao.PersonMapper"/>
    </mappers>
</configuration>

由于使用了注解开发，mapper对应的映射文件就不需要了

db.properties

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf-8
username=root
password=123456

第四步：测试

package Com.fvti.Myabtis.Test;

import Com.fvti.Myabtis.Account.Person;
import Com.fvti.Myabtis.Dao.PersonMapper;
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;
import java.util.List;

public class MybatisPerson {
    public static void main(String[] args) throws IOException {

        Reader resourceAsReader = Resources.getResourceAsReader("Mybatis-Config.xml");
        SqlSessionFactory build = new SqlSessionFactoryBuilder().build(resourceAsReader);
        SqlSession sqlSession = build.openSession();
        PersonMapper mapper = sqlSession.getMapper(PersonMapper.class);
        List<Person> allPerson = mapper.findAllPerson();
        allPerson.forEach(tem->{
            System.out.println(tem);
        });
        sqlSession.close();


    }
}

运行结果：