mybatis框架快速入门

 

通过快速入门示例，我们发现使用mybatis 是非常容易的一件事情，因为只需要编写 dao 接口并且按照

mybatis要求编写两个配置文件，就可以实现功能。远比我们之前的jdbc方便多了。（我们使用注解之后，将变得

更为简单，只需要编写一个mybatis配置文件就够了。）

       1.mybatis的环境搭建

第一步：创建maven工程并导入坐标

第二步：创建实体类和dao的接口

第三步：创建mybatis的主配置文件 sqlmapconifg.xml

第四步：创建映射配置文件  iuserdao.xml

• 创建maven工厂并导入坐标

 1 <?xml version="1.0" encoding="utf-8"?>
 2 
 3 <project xmlns="http://maven.apache.org/pom/4.0.0" xmlns:xsi="http://www.w3.org/2001/xmlschema-instance"
 4   xsi:schemalocation="http://maven.apache.org/pom/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
 5   <modelversion>4.0.0</modelversion>
 6 
 7   <groupid>com.itheima</groupid>
 8   <artifactid>mybatis_eesy_day01_quickstart</artifactid>
 9   <version>1.0-snapshot</version>
10   <packaging>jar</packaging>
11 
12   <name>mybatis_eesy_day01_quickstart</name>
13   <!-- fixme change it to the project's website -->
14   <url>http://www.example.com</url>
15 
16   <properties>
17     <project.build.sourceencoding>utf-8</project.build.sourceencoding>
18     <maven.compiler.source>1.8</maven.compiler.source>
19     <maven.compiler.target>1.8</maven.compiler.target>
20   </properties>
21 
22   <dependencies>
23       <dependency>
24           <groupid>org.mybatis</groupid>
25           <artifactid>mybatis</artifactid>
26           <version>3.4.5</version>
27       </dependency>
28     <dependency>
29       <groupid>mysql</groupid>
30       <artifactid>mysql-connector-java</artifactid>
31       <version>5.1.6</version>
32     </dependency>
33     <dependency>
34       <groupid>log4j</groupid>
35       <artifactid>log4j</artifactid>
36       <version>1.2.17</version>
37     </dependency>
38     <dependency>
39       <groupid>junit</groupid>
40       <artifactid>junit</artifactid>
41       <version>4.11</version>
42       <scope>test</scope>
43     </dependency>
44   </dependencies>
45 
46   <build>
47     <pluginmanagement><!-- lock down plugins versions to avoid using maven defaults (may be moved to parent pom) -->
48       <plugins>
49         <!-- clean lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#clean_lifecycle -->
50         <plugin>
51           <artifactid>maven-clean-plugin</artifactid>
52           <version>3.1.0</version>
53         </plugin>
54         <!-- default lifecycle, jar packaging: see https://maven.apache.org/ref/current/maven-core/default-bindings.html#plugin_bindings_for_jar_packaging -->
55         <plugin>
56           <artifactid>maven-resources-plugin</artifactid>
57           <version>3.0.2</version>
58         </plugin>
59         <plugin>
60           <artifactid>maven-compiler-plugin</artifactid>
61           <version>3.8.0</version>
62         </plugin>
63         <plugin>
64           <artifactid>maven-surefire-plugin</artifactid>
65           <version>2.22.1</version>
66         </plugin>
67         <plugin>
68           <artifactid>maven-jar-plugin</artifactid>
69           <version>3.0.2</version>
70         </plugin>
71         <plugin>
72           <artifactid>maven-install-plugin</artifactid>
73           <version>2.5.2</version>
74         </plugin>
75         <plugin>
76           <artifactid>maven-deploy-plugin</artifactid>
77           <version>2.8.2</version>
78         </plugin>
79         <!-- site lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#site_lifecycle -->
80         <plugin>
81           <artifactid>maven-site-plugin</artifactid>
82           <version>3.7.1</version>
83         </plugin>
84         <plugin>
85           <artifactid>maven-project-info-reports-plugin</artifactid>
86           <version>3.0.0</version>
87         </plugin>
88       </plugins>
89     </pluginmanagement>
90   </build>
91 </project>

• 创建实体类和dao接口

1 public class user implements serializable {
2     private integer id;
3     private string username;
4     private date birthday;
5     private string address;
6     private string sex;

public interface iuserdao {
//    查询所有用户
    list<user> findall();
}

 

• 创建主配置文件

<?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的环境-->
<environments default="mysql">
    <!--配置mysql的环境-->
    <environment id="mysql">
        <!--配置事务的类型-->
        <transactionmanager type="jdbc"></transactionmanager>
        <!--配置数据库的信息，用的是数据源（连接池技术）-->
        <datasource type="pooled">
            <property name="driver" value="com.mysql.jdbc.driver"/>
            <property name="url" value="jdbc:mysql://localhost:3306/eesy_mybatis"/>
            <property name="username" value="root"/>
            <property name="password" value="123"/>
        </datasource>
    </environment>
</environments>

    <!--告知mybatis映射文件的位置-->
    <mappers>
        <mapper resource="com/itheima/dao/iuserdao.xml"/>
    </mappers>
</configuration>

 

• 创建映射文件

<?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="com.itheima.dao.iuserdao">
    <select id="findall" resulttype="com.itheima.domain.user">
        select * from  user
    </select>
</mapper>

 

编写测试代码

package com.itheima;

import com.itheima.dao.iuserdao;
import com.itheima.domain.user;
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.ioexception;
import java.io.inputstream;
import java.util.list;

public class testmybatis {
    public static void main(string[] args) throws ioexception {
        //1.读取配置文件
        inputstream in = resources.getresourceasstream("sqlmapconfig.xml");
        //2.创建sqlsessionfactory的构建者对象
        sqlsessionfactorybuilder builder = new sqlsessionfactorybuilder();
        //3.使用构建者创建工厂对象sqlsessionfactory
        sqlsessionfactory factory = builder.build(in);
        //4.使用sqlsessionfactory创建sqlsession对象
        sqlsession sqlsession = factory.opensession();
        //5.使用sqlsession创建dao的代理对象
        iuserdao userdao = sqlsession.getmapper(iuserdao.class);
        //6.使用代理对象执行查询方法
        list<user> userlist = userdao.findall();
        for (user user :userlist){
            system.out.println(user.tostring());
        }
        //7.释放资源
        sqlsession.close();
        in.close();
    }
}

测试结果

user{id=41, username='老王', birthday=tue feb 27 17:47:08 cst 2018, address='北京', sex='男'}
user{id=42, username='小二王', birthday=fri mar 02 15:09:37 cst 2018, address='北京金燕龙', sex='女'}
user{id=43, username='小二王', birthday=sun mar 04 11:34:34 cst 2018, address='北京金燕龙', sex='女'}
user{id=45, username='传智播客', birthday=sun mar 04 12:04:06 cst 2018, address='北京金燕龙', sex='男'}
user{id=46, username='老王', birthday=wed mar 07 17:37:26 cst 2018, address='北京', sex='男'}
user{id=48, username='小马宝莉', birthday=thu mar 08 11:44:00 cst 2018, address='北京修正', sex='女'}