mybatis整合（手动添加jar包方式）

操作步骤

创建数据库

建立user表

放入数据

1、创建javaweb工程并添加Jar包

用到的jar包

junit 用于测试

mybatis框架：mybatis-3.5.9.jar

mysql数据库：mysql-connector-java-8.0.28.jar

2、添加MyBatis核心配置文件

<?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>
    <!-- 配置内容在这里 -->


</configuration>

driver=com.mysql.cj.jdbc.Driver
url=jdbc:mysql://localhost:3306/mybatis
username=root
password=root

编写”mybatis-config.xml”的配置内容

<?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="database.properties"></properties>
    <typeAliases>
        <package name="entity"/>
    </typeAliases>
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="${driver}"/>
                <property name="url" value="${url}?useUnicode=true&amp;characterEncoding=UTF-8&amp;serverTimezone=UTC&amp;useSSL=false"/>
                <property name="username" value="${username}"/>
                <property name="password" value="${password}"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper resource="mapper/UserMapper.xml"></mapper>
    </mappers>
</configuration>

”mybatis-config.xml”的配置节点说明

1、configuration：

配置文件的根元素节点

2、environments：

表示配置MyBaits的多套运行环境，该元素节点下可以配置多个environment子元素节点

3、environment：

配置Mybaits的一套运行环境，需指定运行环境ID、事务管理(transactionManager)和数据源(dataSource)配置等相关信息

4、mappers：

其下可以配置多个mapper节点来具体指定SQL映射文件的路径，resource属性的值表述了类资源路径下的SQL映射文件的路径

3、创建实体类

package entity;

public class User {

    private String username;
    private String password;
    private Integer age;
    private String sex;
    private String birthDate;

    public User() {
    }

    public User(String username, String password, Integer age, String sex, String birthDate) {
        this.username = username;
        this.password = password;
        this.age = age;
        this.sex = sex;
        this.birthDate = birthDate;
    }

    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;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public String getBirthDate() {
        return birthDate;
    }

    public void setBirthDate(String birthDate) {
        this.birthDate = birthDate;
    }

    @Override
    public String toString() {
        return "User{" +
                "username='" + username + '\'' +
                ", password='" + password + '\'' +
                ", age=" + age +
                ", sex='" + sex + '\'' +
                ", birthDate=" + birthDate +
                '}';
    }
}

注： 1、类的名称不一定和表名相同

2、属性名称和数据库字段名称相同，才能自动映射

3、属性类型需要和数据库字段类型对应

4、每一个属性都要生成get/set方法

4、创建SQL映射文件

<?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="/">
        <!-- SQL映射写在这里 -->
</mapper>

编辑”UserMapper.xml”SQL映射内容

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="/">
    <select id="findAll" resultType="user">
select * from user
    </select>

    <select id="findAll2" resultType="map">
select * from user
    </select>

    <select id="myCount" resultType="int" parameterType="map">
        select count(*) from smbms_bill join smbms_provider on smbms_bill.providerId=smbms_provider.id where smbms_provider.proName like concat('%',#{proName},'%') and isPayment=#{isPayment}
    </select>
</mapper>

<!--建立映射关系-->

配置节点说明

select：表示查询语句

id属性：表示该SQL语句的唯一标识符

resultType属性：表示SQL语句返回值类型，此处通过SQL语句查询数据，将数据直接映射到User实体类上

5、代码测试，输出结果

import entity.User;
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 org.junit.Test;

import java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class UserMapperTest {
    @Test
    public void Test01() throws IOException {
        System.out.println(" = ");
        InputStream inputStream = Resources.getResourceAsStream("mybatis-config.xml");
        SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();
        SqlSessionFactory build = sqlSessionFactoryBuilder.build(inputStream);
        SqlSession sqlSession = build.openSession();
        List<User> findAll = sqlSession.selectList("findAll");
        for (User user: findAll) {
            System.out.println("user = " + user);
        }
        sqlSession.close();
    }

    @Test
    public void Test02() throws IOException {

        InputStream inputStream = Resources.getResourceAsStream("mybatis-config.xml");
        SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();
        SqlSessionFactory build = sqlSessionFactoryBuilder.build(inputStream);
        SqlSession sqlSession = build.openSession();
        List<Map<String,Object>> findAll = sqlSession.selectList("findAll2");
        for (Map<String, Object> stringObjectMap : findAll) {
            System.out.println("stringObjectMap = " + stringObjectMap);
        }
        sqlSession.close();
    }

  
}

结果为list集合对象