一、简介：什么是MyBatis
1.MyBatis是一款优秀的持久层框架，支持定制化SQL、存储过程以及高级映射。MyBatis避免了几乎所有的JDBC代码和手动设置参数以及获取结果集。MyBatis可以使用简单的XML或者注解来配置和映射原生信息，将接口和Java的POJOs映射成数据库中的记录
二、入门
1.安装mybatis-x.x.x.jar将文件置于classpath即可，使用maven来构造项目，则需要将下面的dependency代码放在pom.xml文件中：
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>x.x.x</version>
</dependency>
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.2.1</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.17</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
</dependency>
2.创建数据库
create database mybatis;
3.创建users表
create table users(id int primary key auto_increment,name varchar(20),age int)
4.创建必要的包
com.jd.ssm.dao.impl
com.jd.ssm.service.impl
com.jd.ssm.dao.domain
com.jd.ssm.util
com.jd.ssm.ssm.web.controller
5.测试连接
package com.jd.ssm.mybatisdao; 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; public class APP {
public static void main(String[] args){
try{
//指定配置文件的类路径
String resource ="mybatis-config.xml";
//加载文件，形成输入流
InputStream inputStream = Resources.getResourceAsStream(resource);
//创建会话工厂，相当于连接池
SqlSessionFactory sf=new SqlSessionFactoryBuilder().build(inputStream);
//通过sf开启会话，相当于打开连接了
SqlSession s= sf.openSession();
System.out.println(s);
} catch ( Exception e) {
e.printStackTrace();
}
}
}
6.编写mapper文件
a)创建User类，和users对应
package com.jd.ssm.domain;
public class User {
private Integer id;
private String name;
private int age;
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 int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
}b).创建UserMapper.xml映射文件
<?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="users">
<insert id="insert">
insert into users(name,age) values(#{name},#{age});
</insert>
</mapper>
三、复杂应用
1.准备数据
sql.sql
source C:\Users\shizeqi\Desktop\sql.sql
2.创建java类
(1)User类
package com.jd.ssm.domain;
public class User {
private Integer id;
private String name;
private int age;
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 int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
}(2)Order类
package com.jd.ssm.domain; //创建订单类
public class Order {
private Integer id ;
private String orderNo; public Integer getId() {
return id;
} public void setId(Integer id) {
this.id = id;
} public String getOrderNo() {
return orderNo;
} public void setOrderNo(String orderNo) {
this.orderNo = orderNo;
} public User getUser() {
return user;
} public void setUser(User user) {
this.user = user;
} //这个地方需要用到uid，直接加上User就可以
private User user; }
(3)Item类
package com.jd.ssm.domain; /*
* 订单项
* */
public class Item {
private Integer id;
private String itemName;
private Order order ; public Integer getId() {
return id;
} public void setId(Integer id) {
this.id = id;
} public String getItemName() {
return itemName;
} public void setItemName(String itemName) {
this.itemName = itemName;
} public Order getOrder() {
return order;
} public void setOrder(Order order) {
this.order = order;
}
}
3.创建订单Order映射文件
[resource/OrderMapper.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="orders">
<insert id="insert">
insert into orders(orderno,uid) values(#{orderNo},#{user.id});
</insert>
</mapper>