Mybatis(一)

pom.xml配置

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>StudentControl</artifactId>
    <version>1.0-SNAPSHOT</version>
    <dependencies>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.5</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.21</version>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.13</version>
        </dependency>
    </dependencies>

</project>

src/main/java/com/XXX

src/main/java/com/XXX/domain

这个domain包下放的是实现类的JavaBean
数据库结构

public class Student {
    private String Sno;
    private String Sname;
    private Integer Sage;
    private String Ssex;

    public String getSno() {
        return Sno;
    }

    public void setSno(String sno) {
        Sno = sno;
    }

    public String getSname() {
        return Sname;
    }

    public void setSname(String sname) {
        Sname = sname;
    }

    public Integer getSage() {
        return Sage;
    }

    public void setSage(Integer sage) {
        Sage = sage;
    }

    public String getSsex() {
        return Ssex;
    }

    public void setSsex(String ssex) {
        Ssex = ssex;
    }

    @Override
    public String toString() {
        return "Student{" +
                "Sno='" + Sno + '\'' +
                ", Sname='" + Sname + '\'' +
                ", Sage=" + Sage +
                ", Ssex='" + Ssex + '\'' +
                '}';
    }
}

src/main/java/com/XXX/dao

这个dao包下放的是接口

/**
 * 持久层接口
 */
public interface IStudentDao {
    /**
     * 查询所有操作
     * @return
     */
    // @Select("select * from user")
    List<Student> findAll();
}

src/main/resources

com/XXX/dao(这个一定要一步一步建立文件夹不能一蹴而就）

存放IStudentDao.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="com.zyf.dao.IStudentDao">
    <select id="findAll" resultType="com.zyf.domain.Student">
        select * from student
    </select>
</mapper>

jdbcConfig.properties

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/数据库名?serverTimezone=UTC
jdbc.username=
jdbc.password=

log4j.properties（直接复制）

# Set root category priority to INFO and its only appender to CONSOLE.
#log4j.rootCategory=INFO, CONSOLE            debug   info   warn error fatal
log4j.rootCategory=debug, CONSOLE, LOGFILE

# Set the enterprise logger category to FATAL and its only appender to CONSOLE.
log4j.logger.org.apache.axis.enterprise=FATAL, CONSOLE

# CONSOLE is set to be a ConsoleAppender using a PatternLayout.
log4j.appender.CONSOLE=org.apache.log4j.ConsoleAppender
log4j.appender.CONSOLE.layout=org.apache.log4j.PatternLayout
log4j.appender.CONSOLE.layout.ConversionPattern=%d{ISO8601} %-6r [%15.15t] %-5p %30.30c %x - %m\n

# LOGFILE is set to be a File appender using a PatternLayout.
log4j.appender.LOGFILE=org.apache.log4j.FileAppender
log4j.appender.LOGFILE.File=d:\axis.log
log4j.appender.LOGFILE.Append=true
log4j.appender.LOGFILE.layout=org.apache.log4j.PatternLayout
log4j.appender.LOGFILE.layout.ConversionPattern=%d{ISO8601} %-6r [%15.15t] %-5p %30.30c %x - %m\n

SqlMapConfig.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">
<!--mybatis的主配置文件-->
<configuration>
    <properties resource="jdbcConfig.properties">
    </properties>
    <!--配置环境-->
    <environments default="mysql">
        <!--配置mysql的环境-->
        <environment id="mysql">
            <!--配置事务的类型-->
            <transactionManager type="JDBC"></transactionManager>
            <!--配置数据源（连接池）-->
            <dataSource type="POOLED">
            <!--配置连接数据库的4个基本信息-->
                <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>

    <!--指定映射配置文件的位置，映射配置文件指的是每个dao独立的配置文件
    如果使用注解 则这里是用class来指定被注解的dao类全限定名称-->
    <mappers>
       <mapper resource="com/zyf/dao/IStudentDao.xml"></mapper>
    </mappers>

</configuration>

src/test

新建java/com.XXX.test存放测试类

public class MybatisTest {
    private InputStream in;
    private SqlSession session;
    private IStudentDao userDao;
    @Before//在Test之前使用
    public void init() throws Exception{
        //1.读取配置文件
        in = Resources.getResourceAsStream("SqlMapConfig.xml");
        //2.创建SqlSessionFactory工厂
        SqlSessionFactoryBuilder builder=new SqlSessionFactoryBuilder();
        SqlSessionFactory factory=builder.build(in);
        //3.使用工厂创建SqlSession对象
        session=factory.openSession();
        //4.使用SqlSession创建Dao接口的代理对象
        userDao=session.getMapper(IStudentDao.class);
    }
    @After//在Test之后使用
    public void destroy()throws Exception{
        //事务回滚
        session.commit();
        //6.释放资源
        session.close();
        in.close();
    }

    /**
     * 测试查询所有方法
     */
    @Test
    public void testFindALL(){
        //5.执行代理对象方法
        List<Student> users=userDao.findAll();
        for(Student student:users){
            System.out.println(student);
        }
    }
}