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'}