Mybatis框架 的快速入门

MyBatis

 简介

什么是 MyBatis?

MyBatis 是支持普通 SQL 查询,存储过程和高级映射的优秀持久层框架。MyBatis 消除 了几乎所有的 JDBC 代码和参数的手工设置以及结果集的检索。MyBatis 使用简单的 XML 或注解用于配置和原始映射,将接口和 Java 的 POJOs(Plan Old Java Objects,普通的 Java 对象)映射成数据库中的记录。

Mybatis快速入门

1.添加jar包

mybatis：

  mybatis-3.1.1.jar

oracle：

 ojdbc6.jar（根据个人情况，不同数据库选择相应的包）

2.表

create table user_name (id number,name varchar2(200),age number);

insert into user_name values(1,'ddd',23);

insert into user_name values(2.'fff',24)

3.添加mybatis的配置文件config.xm

1 <?xml version="1.0" encoding="UTF-8"?>
 2 
 3 <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">
 4 
 5 <configuration>
 6 
 7          <environments default="development">
 8 
 9                    <environment id="development">
10 
11                             <transactionManager type="JDBC" />
12 
13                             <dataSource type="POOLED">
14 
15                                      <property name="driver" value="oracle.jdbc.driver.OracleDriver" />
16 
17                                      <property name="url" value="jdbc:oracle:thin:@localhost:1521:Oracle" />
18 
19                                      <property name="username" value="root" />
20 
21                                      <property name="password" value="root" />
22 
23                             </dataSource>
24 
25                    </environment>
26 
27          </environments>
28 
29 </configuration>

4.定义表所对应的实体类

package cn.zr.maybatis;

public class User {
 
    private String id;
    
    private String userName;
    
    private String passWord;

    public User() {
        super();
        // TODO Auto-generated constructor stub
    }

    public User(String id, String userName, String passWord) {
        super();
        this.id = id;
        this.userName = userName;
        this.passWord = passWord;
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public String getPassWord() {
        return passWord;
    }

    public void setPassWord(String passWord) {
        this.passWord = passWord;
    }

    @Override
    public String toString() {
        return "User [id=" + id + ", userName=" + userName + ", passWord=" + passWord + "]";
    }
    
    
    
}

5.定义操作user_name表的sql映射文件userMapper.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="cn.zr.mybatis.userMapper"> 
<select id="getUser" parameterType="int" 
resultType="cn.zr.mybatis.User">
select * from user_name where id=#{id}
</select>
</mapper>

6.在config.xml文件中注册userMapper.xml文件

<mappers>
<mapper resource="cn/zr/mybatis/userMapper.xml"/>
</mappers>

7.编写测试代码，执行定义的select语句

public class Test {

         public static void main(String[] args) throws IOException {

                   String resource = "config.xml";

                   //加载mybatis的配置文件（它也加载关联的映射文件）

                   Reader reader = Resources.getResourceAsReader(resource);

                   //构建sqlSession的工厂

                   SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader);

                   //创建能执行映射文件中sql的sqlSession

                   SqlSession session = sessionFactory.openSession();

                   //映射sql的标识字符串

                   String statement = "com.atguigu.mybatis.bean.userMapper"+".selectUser";

                   //执行查询返回一个唯一user对象的sql

                   User user = session.selectOne(statement, 1);

                   System.out.println(user);

                  session.commit();

                  session.close();

         }

}