Mybatis 系列1-入门

首先创建一个maven工程

jdk使用1.8

目录结构：

 

 

1、在pom文件中添加

<packaging>jar</packaging>
    <dependencies>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.3</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.6</version>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.12</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
    </dependencies>

2、创建User实体类     com.mantishell.domain.User.java

public class User implements Serializable {
    private Integer id;
    private String name;
    private String address;
    private String sex;
    private Date birthday;

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", address='" + address + '\'' +
                ", sex='" + sex + '\'' +
                ", birthday=" + birthday +
                '}';
    }

    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 getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    public String getSex() {
        return sex;
    }

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

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    public User(Integer id, String name, String address, String sex, Date birthday) {
        this.id = id;
        this.name = name;
        this.address = address;
        this.sex = sex;
        this.birthday = birthday;
    }

    public User() {
    }
}

3、创建持久层接口IUserDao    com.mantishell.dao.IUserDao.java

public interface IUserDao {

    List<User> findAll();
}

4、在resource添加SqlMapConfig.xml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>
    <!--配置环境，default的名称可以随便填写，填写后environment里必须要有该defaullt的内容-->
    <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">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/db1"/>
                <property name="username" value="root"/>
                <property name="password" value="123456"/>
            </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-->
    <mappers>
        <!--resource指定文件的位置-->
        <mapper resource="com/mantishell/dao/IUserDao.xml" />
    </mappers>
</configuration>

5、在resource下创建持久层接口的映射文件  com.mantishell.dao.IUserDao.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">
<!--namespace写的是dao（持久层接口）的全限定类名-->
<mapper namespace="com.mantishell.dao.IUserDao">
    <!--id是dao的方法名称；resultType表示返回的类型-->
    <select id="findAll" resultType="com.mantishell.domain.User" >
        select * from user
    </select>
</mapper>

6、表的内容

CREATE TABLE `user` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(50) DEFAULT NULL,
  `address` varchar(100) DEFAULT NULL,
  `sex` varchar(10) DEFAULT NULL,
  `birthday` date DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8

7、测试

可以写个main方法

public static void main(String[] args) throws Exception{
        //1、读取配置
        InputStream in = Resources.getResourceAsStream("SqlMapConfig.xml");
        //2、创建SqlSessionFactory工厂
        SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();//创建工厂  mybatis使用了构建者模式，构建者模式：把对象的创建细节隐藏，使使用者直接调用方法即可拿到对象。
        SqlSessionFactory factory = builder.build(in);//builder就是构建者
        //3、使用工厂生产SqlSession对象
        SqlSession session = factory.openSession();//生产SqlSession  使用了工厂模式
        //4、使用SqlSession创建Dao接口的代理对象
        IUserDao userDao = session.getMapper(IUserDao.class);//创建Dao接口实现类 使用了代理模式
        //5、使用代理对象执行方法
        List<User> users = userDao.findAll();
        for (User user : users) {
            System.out.println(user);
        }
        //6、释放资源
        session.close();
        in.close();
    }

 8、log4j 配置文件

# 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=e:/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