一、新建Maven项目
1）打开IDEA开发工具，点击"Create New Project"
2)选择左侧的"Maven"，点Next
3）填入"GroupId"和“ArtifactId”:
4)Finish
Mave项目新建完成后，项目结构如下：
image.png
二、导入依赖，编写实体类及其配置文件：
1)在"pom.xml"中导入需要的依赖：
<?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>com.zl</groupId>
<artifactId>hello_mybatis</artifactId>
<version>1.0-SNAPSHOT</version>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<source>8</source>
<target>8</target>
</configuration>
</plugin>
</plugins>
</build>
<packaging>jar</packaging>
<dependencies>
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.4.5</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.32</version>
</dependency>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.17</version>
</dependency>
</dependencies>
</project>
2）src.main.java包下新建com.zl.domain包，然后新建实体类User:
package com.zl.domain;
import java.io.Serializable;
import java.util.Date;
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 + '\'' +
'}';
}
}
3)新建com.zl.dao包，然后新建UserDao接口:
新增一个查询方法：
package com.zl.dao;
import com.zl.domain.User;
import java.util.List;
public interface UserDao {
/**
* 查询所有用户
* @return
*/
List<User> findAll();
}
4)在src.main.resources下新建com.zl.dao包，然后新建UserDao.xml:
注意:resources下的包结构必须和java包下的路径结构一致，还需要注意的是，resources文件夹下无法一次新建com.zl.dao包，只能一级一级的新建目录。
<?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.zl.dao.UserDao">
<!--查询所有-->
<select id="findAll" resultType="com.zl.domain.User">
select * from user
</select>
</mapper>
5)在resources根目录下新建SqlMapConfig.xml主配置文件：
<?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mybatis环境-->
<environments default="mysql">
<!--配置mysql环境-->
<environment id="mysql">
<!--配置事务类型-->
<transactionManager type="JDBC"></transactionManager>
<!--配置数据库信息：用的是数据源（连接池）-->
<dataSource type="POOLED">
<property name="driver" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/mybatis"/>
<property name="username" value="root"/>
<property name="password" value="root"/>
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="com/zl/dao/UserDao.xml" />
</mappers>
</configuration>
三、新建测试类：
1)在src.test.java包下新建UserTest测试类：
import com.zl.dao.UserDao;
import com.zl.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 org.junit.Test;
import java.io.IOException;
import java.io.InputStream;
import java.util.List;
public class UserTest {
@Test
public void testFindAll(){
try {
//1.读取配置文件
InputStream in = Resources.getResourceAsStream("SqlMapConfig.xml");
//2.创建session工厂
SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(in);
//3.创建session
SqlSession sqlSession = factory.openSession();
//4.获取dao接口的代理对象
UserDao userDao = sqlSession.getMapper(UserDao.class);
//5.执行方法
List<User> users = userDao.findAll();
//6.输出语句
users.stream().forEach(System.out::println);
//7.释放资源
sqlSession.close();
in.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
四、数据库表：
User表：
DROP TABLE IF EXISTS `user`;
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;
插入数据：
insert into 'user'('id','sername','birthday','sex','address'
values (41,'张三','2018-02-27 17:33:08','男','上海'),
(42,'张小宝','2019-03-02 15:09:24','女','上海徐家汇'),
(43,'张大宝','2019-03-04 11:34:12','女','上海长宁'),
(45,'杨过','2019-03-04 14:07:08','男','上海浦东'),
(46,'小龙女','2019-03-07 13:11:56','女','上海'),
(48,'哈哈哈','2018-09-08 12:33:01','女','上海徐家汇');
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