案例所用工具:
IDEA2018,Navicat
1 准备案例所需数据
打开navicat,新建数据库mybatis_learn.在数据库中新建查询.
CREATE TABLE `user` (
`id` int(11) NOT NULL auto_increment,
`username` varchar(32) NOT NULL COMMENT '用户名称',
`birthday` datetime default NULL COMMENT '生日',
`sex` char(1) default NULL COMMENT '性别',
`address` varchar(256) default NULL COMMENT '地址',
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
insert into `user`(`id`,`username`,`birthday`,`sex`,`address`) values (41,'老王','2018-02-27 17:47:08','男','北京'),(42,'小二王','2018-03-02 15:09:37','女','北京金燕龙'),(43,'小二王','2018-03-04 11:34:34','女','北京金燕龙'),(45,'传智播客','2018-03-04 12:04:06','男','北京金燕龙'),(46,'老王','2018-03-07 17:37:26','男','北京'),(48,'小马宝莉','2018-03-08 11:44:00','女','北京修正');
运行查询后,得到如下数据.
user表的设计
user表的数据
2 建立maven工程
2.1 建立工程项目之前,先建立文件夹用于存放工程.
2.2 新建空的project,命名为mybatis_learn01,将它作为项目的工作空间.
2.3 等idea弹出窗口后,记得配置Project SDK和Project language level.
2.4 新建mybatis_01demo,作为入门模块
3 引入依赖
在pom.xml文件中配置项目依赖
<!--配置打包方式-->
<packaging>jar</packaging>
<dependencies>
<!--mybatis核心配置文件依赖-->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.4.5</version>
</dependency>
<!--mysql数据库连接依赖-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.47</version>
</dependency>
<!--junit测试类依赖-->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
</dependency>
<!--log4j日志记录依赖-->
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.12</version>
</dependency>
</dependencies>
4 建立mybatis核心配置文件
4.1 在resources右键新建文件SqlMapConfig.xml
4.2 在SqlMapConfig.xml中编写配置
<?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主配置文件-->
<configuration>
<!--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">
<!--配置连接数据库的四个基本信息-->
<property name="driver" value="com.mysql.jdbc.Driver" />
<property name="url" value="jdbc:mysql://localhost:3306/mybatis_learn />
<property name="username" value="root" />
<property name="password" value="1234" />
</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>
<mapper resource="com/cncs/dao/UserDao.xml"/>
</mappers>
</configuration>
4.3 在resources右键新建文件,建立log4j.properties,该文件是log4j初始化必须文件
# 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=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
5 建立User实体类
5.1 建立包com.cncs.domain
5.2 建立User对象
public class User implements Serializable {
private Integer id;
private String username;
private Date birthday;
private String sex;
private String address;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public Date getBirthday() {
return birthday;
}
public void setBirthday(Date birthday) {
this.birthday = birthday;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", username='" + username + '\'' +
", birthday=" + birthday +
", sex='" + sex + '\'' +
", address='" + address + '\'' +
'}';
}
}
6 建立UserDao接口
6.1 建立包com.cncs.dao
6.2 建立UserDao接口
/**
* 用户的持久层接口
*/
public interface UserDao {
/**
* 查询所有用户
*
* @return
*/
List<User> findAll();
}
7 建立UserDao.xml关系映射文件
7.1 按照UserDao包结构建立文件夹.(注:在resources中只能建立目录)
7.2 新建UserDao.xml配置文件(可以写UserMapper.xml,此处为了方便展示与UserDao接口的映射关系)
7.3 编写UserDao.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.cncs.dao.UserDao">
<!--配置查询所有-->
<select id="findAll" resultType="com.cncs.domain.User">
select * from user;
</select>
</mapper>
8 建立UserTest测试类
8.1 在test中建立com.cncs.test包
8.2 建立MybatisTest测试类
package com.cncs.test;
import com.cncs.dao.UserDao;
import com.cncs.domain.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 java.io.InputStream;
import java.util.List;
public class MybatisTest {
public static void main(String[] args) throws Exception{
//1.读取配置文件
InputStream in = Resources.getResourceAsStream("SqlMapConfig.xml");
//2.创建SqlSessionFactory对象
SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
SqlSessionFactory factory = builder.build(in);
//3.通过factory对象创建SqlSession
SqlSession sqlSession = factory.openSession();
//4.通过session对象创建代理对象
UserDao userDao= sqlSession.getMapper(UserDao.class);
//5.执行dao方法
List<User> users = userDao.findAll();
//遍历列表集合
for (User user : users) {
System.out.println(user);
}
//6.释放资源
sqlSession.close();
in.close();
}
}
9 测试案例
测试结果如下
