Mybatis入门(一)之操作数据库

 

 

Whats Mybatis

 

持久层框架, 替代MVC层中DAO,因为DAO 层的要求就是
:能与数据库交互的靶子、 能执行SQL语句。

 

不同于JDBC的connection,MyBatis 中有个SqlSession
,什么是SqlSession,以及它的法力是哪些:

 

 

1 向SQL语句流传参数

 

2执行SQL语句

 

3 获取执行SQL语句的结果

 

4 事务的决定

 

哪些得到SqlSession

 

1 通过配备文件获取数据库连接的相关要求

 

2 通过配备文件构建SqlSessionFactory

 

3 通过SqlSessionFactory 打开openSession

 

 

 

下面看代码具体操作:

 

目录结构:

 

 图片 1

 

MyBatis 配置文件

MySQL-connector…….对应的驱动文件

Ojdbc14.jar……..oracle 对应的驱动文件

 图片 2

Userinfo.java(数据库对应的实体类)

package bean;

public class Userinfo {

    private String uname;
    private String upass;
    private int id;


    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getUname() {
        return uname;
    }
    public void setUname(String uname) {
        this.uname = uname;
    }
    public String getUpass() {
        return upass;
    }
    public void setUpass(String upass) {
        this.upass = upass;
    }

}

Mapper

 1 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 2 <!DOCTYPE mapper
 3     PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
 4     "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
 5   
 6 <mapper namespace="UserinfoMapper">
 7     <!--  
 8     public String getuser (int id){}
 9     -->
10     <select id="getuser" parameterType="int" resultType="java.lang.String" >
11          select uname from userinfo where id=#{id}
12     </select>
13 </mapper>

Test

 1 package Test;
 2 
 3 import java.io.InputStream;
 4 
 5 import org.apache.ibatis.io.Resources;
 6 import org.apache.ibatis.session.SqlSession;
 7 import org.apache.ibatis.session.SqlSessionFactory;
 8 import org.apache.ibatis.session.SqlSessionFactoryBuilder;
 9 
10 
11 
12 
13 public class Demo {
14 
15     /**
16      * 
17      * 测试连接数据库,执行SQL语句
18      */
19     public static void main(String[] args) throws Exception {
20         // TODO Auto-generated method stub
21 
22         // 加载Mybatis的主配置文件
23         InputStream is = Resources.getResourceAsStream("SqlMapConfig.xml");
24         
25         // 创建生产session的工厂类 session不是作用域 -- 相当于connection
26         SqlSessionFactoryBuilder sfb = new SqlSessionFactoryBuilder();
27         SqlSessionFactory ssf = sfb.build(is);
28         // 打开session
29         SqlSession session=ssf.openSession();
30         //执行sql语句
31         /**
32          * UserinfoMapper 是UserinfoMapper.xml namespace 的名字
33          * getuser select id 对应的方法名字
34          * 3 是传的参数
35          */
36         
37         String  name=session.selectOne("UserinfoMapper.getuser", 3);
38         System.out.println("name:"+ name);
39         session.close();
40         System.out.println("over");
41         
42     }
43 
44 }

SqlMapConfig.xml

<?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>
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC" />
            <!-- 配置数据源 相当于JDBC连接数据库
              Class.forName("oracle.jdbc.driver.OracleDriver");
              String user = "scott";
               String password = "tiger";
              String url = "jdbc:oracle:thin:@localhost:1521:orcl";
            -->
            <dataSource type="POOLED">
                <property name="driver" value="oracle.jdbc.driver.OracleDriver"/>
                <property name="url" value="jdbc:oracle:thin:@localhost:1521:orcl"/>
                <property name="username" value="scott" />
                <property name="password" value="tiger" />
            </dataSource>
        </environment>
    </environments>
    <!-- 读取Mapper包下的UserinfoMapper.xml文件 -->
    <mappers>
        <mapper resource="Mapper/UserinfoMapper.xml" />
    </mappers>
</configuration>

 

支配台出口的文件

图片 3

 

网站地图xml地图