Mybatis相關知識-lxd

mybatis：是一個優秀的基于java的持久層架構，内部封裝了jdbc，使開發者隻需要關注SQL語句本身

Mybatis 架構快速入門

1. 導入坐标
2. 編寫實體類
3. 編寫持久層接口
4. 編寫持久層接口的映射檔案（建立位置：必須和持久層接口在相同的包中，名稱必須以持久層接口名稱命名檔案名，擴充名是.xml）
5. 編寫SqlMapConfig.xml配置檔案
6. 編寫測試檔案

//1.導入坐标
<dependencies>
 <dependency>
 <groupId>org.mybatis</groupId>
 <artifactId>mybatis</artifactId>
 <version>3.4.5</version>
 </dependency>
 <dependency>
 <groupId>junit</groupId>
 <artifactId>junit</artifactId>
 <version>4.10</version>
 <scope>test</scope>
 </dependency>
 <dependency>
 <groupId>mysql</groupId>
 <artifactId>mysql-connector-java</artifactId>
 <version>5.1.6</version>
 <scope>runtime</scope>
 </dependency>
 <dependency>
 <groupId>log4j</groupId>
 <artifactId>log4j</artifactId>
 <version>1.2.12</version>
 </dependency>
 </dependencies>
           

//編寫實體類
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 + "]";
}
}
           

//編寫持久層接口
public interface IUserDao {
/**
* 查詢所有使用者
* @return
*/
List<User> findAll();
}
           

//編寫持久層接口的映射檔案
<?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.itheima.dao.IUserDao">
<!-- 配置查詢所有操作 -->
<select id="findAll" resultType="com.itheima.domain.User">
select * from user
</select>
           

//編寫SqlMapConfig.xml配置檔案
<?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 的環境 -->
<environments default="mysql">
<!-- 配置 mysql 的環境 -->
<environment id="mysql">
<!-- 配置事務的類型 -->
<transactionManager type="JDBC"></transactionManager>
<!-- 配置連接配接資料庫的資訊：用的是資料源(連接配接池) -->
<dataSource type="POOLED">
<property name="driver" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/ee50"/>
<property name="username" value="root"/>
<property name="password" value="1234"/>
</dataSource>
</environment>
</environments>
<!-- 告知 mybatis 映射配置的位置 -->
<mappers>
<mapper resource="com/itheima/dao/IUserDao.xml"/>
</mappers>
</configuration>
           

//編寫測試類
public class MybatisTest {
public static void main(String[] args)throws Exception {
	//1.讀取配置檔案
	InputStream in = Resources.getResourceAsStream("SqlMapConfig.xml");
	//2.建立 SqlSessionFactory 的建構者對象
	SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
	//3.使用建構者建立工廠對象 SqlSessionFactory
	SqlSessionFactory factory = builder.build(in);
	//4.使用 SqlSessionFactory 生産 SqlSession 對象
	SqlSession session = factory.openSession();
	//5.使用 SqlSession 建立 dao 接口的代理對象
	IUserDao userDao = session.getMapper(IUserDao.class);
	//6.使用代理對象執行查詢所有方法
	List<User> users = userDao.findAll();
	for(User user : users) {
	System.out.println(user);
	}
	//7.釋放資源
	session.close();
	in.close();
	}
}