初识框架之MyBatis

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <!-- xml文件的头文件，起到对文件的约束作用(例如:必须存在哪些节点) -->
 3 <!DOCTYPE configuration
 4         PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
 5         "http://mybatis.org/dtd/mybatis-3-config.dtd">
 6 <configuration>
 7     <!--指向配置文件-->
 8     <properties resource="database.properties"></properties>
 9     <!--声明别名-->
10     <typeAliases>
11         <!--第一种方法-->
12         <!--<typeAlias type="com.cn.Dao.类名" alias="Monkey"></typeAlias>-->
13         <!--第二种方法，这玩意好用,别名就是其类名-->
14         <package name="com.cn.entity"></package>
15     </typeAliases>
16     <environments default="development">
17         <environment id="development">
18             <!--事务管理器:type JDBC or UNSIGNED(托管)-->
19             <transactionManager type="JDBC"></transactionManager>
20             <!--数据源:type jndi pooled unpooled-->
21             <dataSource type="POOLED">
22                 <!--连接数据库的4个连接参数-->
23                 <property name="driver" value="${driver}"></property>
24                 <property name="url" value="${url}"></property>
25                 <property name="username" value="${username}"></property>
26                 <property name="password" value="${password}"></property>
27             </dataSource>
28         </environment>
29     </environments>
30     <!--指向小配置文件xml-->
31     <mappers>
32         <package name="com.cn.Dao"></package>
33     </mappers>
34 </configuration>

 1 <build>
 2   <resources>
 3     <resource>
 4       <directory>src/main/java</directory>
 5       <includes>
 6         <include>**/*.xml</include>
 7       </includes>
 8     </resource>
 9   </resources>
10 </build>

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <!DOCTYPE mapper
 3         PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
 4         "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
 5 <!--namespace:该属性值为本配置文件所指向的接口的相对路径-->
 6 <mapper namespace="com.cn.Dao.UserDao">
 7     <!--增加语句-->
 8     <insert id="addUser" parameterType="User"><!--这里id为接口中的方法名，parameterType入参的类型(设置了configuration.xml中的别名这里就是该别名了，否则就是全类名)-->
 9         insert into user values(default ,#{name},#{pwd})/*如果接口的入参是对象，那么这里的name和pwd就是对象中的属性名*/
10     </insert>
11     <!--修改语句-->
12     <update id="updateUser" parameterType="User">
13         update user set name=#{name},pwd=#{pwd} where id=#{id}
14     </update>
15     <!--删除语句-->
16     <delete id="delUser" parameterType="int">
17         delete from user where id=#{id}/*如果接口的入参是基本类型，那么这里的id就是其变量名*/
18     </delete>
19     <!--查询语句-->
20     <select id="getUser" parameterType="int" resultType="User">/*resultType是返回值的类型*/
21         select * from user where id=#{id}
22     </select>
23 </mapper>

 1 package com.cn.util;
 2 
 3 import org.apache.ibatis.session.SqlSessionFactory;
 4 import org.apache.ibatis.session.SqlSessionFactoryBuilder;
 5 
 6 import java.io.InputStream;
 7 
 8 public class SqlSessionUtil {
 9     private static SqlSessionFactory factory;
10     public static SqlSessionFactory getFactory(){
11         if (factory==null){
12             SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
13             //将配置文件configuration.xml，也就是最外层的配置Mybatis的xml文件放转换成流
14             InputStream is = SqlSessionUtil.class.getResourceAsStream("/configuration.xml");
15             //获取工厂
16             factory = builder.build(is);
17         }
18         return factory;
19     }
20 }

package com.cn.Dao;

import com.cn.entity.User;
import com.cn.util.SqlSessionUtil;
import org.apache.ibatis.session.SqlSession;


public class UserDaoImpl implements UserDao {
    @Override
    public void addUser(User user) {
        //获取会话（SqlSessoin）对象
        SqlSession session = SqlSessionUtil.getFactory().openSession();
        try {
            //把入参传入该会话的insert房中，其中“addUser为接口中的方法名，也就是小配置文件中的id属性”
            session.insert("addUser", user);
            //提交事务
            session.commit();
        } catch (Exception e) {
            //如果发生异常，回滚事务
            session.rollback();
        } finally {
            //最后必须要把此次会话关闭
            session.close();
        }
    }

    @Override
    public void delUser(int id) {
        SqlSession session = SqlSessionUtil.getFactory().openSession();
        try {
            session.delete("delUser", id);
            session.commit();

        } catch (Exception e) {
            session.rollback();
        } finally {
            session.close();
        }
    }

    @Override
    public void updateUser(User user) {
        SqlSession session = SqlSessionUtil.getFactory().openSession();
        try {
            session.update("updateUser", user);
            session.commit();
        } catch (Exception e) {
            session.rollback();
        } finally {
            session.close();
        }
    }

    @Override
    public User getUser(int id) {
        SqlSession session = SqlSessionUtil.getFactory().openSession();
        try {
            User getUser = (User)session.selectOne("getUser", id);
            session.commit();
            return getUser;
        } catch (Exception e) {
            session.rollback();
        } finally {
            session.close();
        }
        return null;
    }
}

package com.cn.text;

import com.cn.Dao.UserDao;
import com.cn.Dao.UserDaoImpl;
import com.cn.entity.User;
import org.junit.Test;

public class TextMybatis {
    UserDao ud= new UserDaoImpl();
    @Test
    public void test1(){
        User user=new User(-1,"sjdf","123");
        ud.addUser(user);
    }
    @Test
    public void test2(){
        User user=new User(1,"山间的风","789132");
        ud.updateUser(user);
    }
    @Test
    public void test3(){
        ud.delUser(1);
    }
    @Test
    public void test4(){
        User user = ud.getUser(1);
        System.out.println(user.toString());
    }
}