mybatis详解

首先就是hello world

maven配置

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.test02.service</groupId> <artifactId>service-say-hi</artifactId> <version>0.0.1</version> <dependencies> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.10</version> </dependency> <dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis</artifactId> <version>3.4.0</version> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.18</version> </dependency> </dependencies> </project>

UserDao.java

package com.test.dao; import com.test.model.User; /** * Created by lion on 17/3/8. */ public interface UserDao { User findUserById(String id); }

User.java

package com.test.model; import java.io.Serializable; /** * Created by lion on 17/3/8. */ public class User implements Serializable { private String name; private int age; private String hobby; public String getName() { return name; } public void setName(String name) { this.name = name; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } public String getHobby() { return hobby; } public void setHobby(String hobby) { this.hobby = hobby; } }

SessionFactoryUtil.java

package com.test.mybatis; 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; /** * Created by lion on 17/3/8. */ public class SqlSessionFactoryUtil { private static SqlSessionFactory sqlSessionFactory; public static SqlSessionFactory getSqlSessionFactory() { if (sqlSessionFactory == null) { InputStream inputStream = null; try { inputStream = Resources.getResourceAsStream("mybatis-config.xml"); sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream); } catch (IOException e) { e.printStackTrace(); } } return sqlSessionFactory; } public static SqlSession openSession() { return getSqlSessionFactory().openSession(); } }

TestMain.java

package com.test.mybatis; import com.test.dao.UserDao; import com.test.model.User; import org.apache.ibatis.session.SqlSession; /** * Created by lion on 17/3/8. */ public class TestMain { public static void main(String[] args) { SqlSession sqlSession = SqlSessionFactoryUtil.openSession(); UserDao userDao = sqlSession.getMapper(UserDao.class); String id = "1"; User users = userDao.findUserById(id); System.out.println(users.getName()); } }

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="com.test.dao.UserDao"> <select id="findUserById" parameterType="String" resultType="com.test.model.User"> select * from user where id=#{id} </select> </mapper>

jdbc.properties

jdbc.driverClassName=com.mysql.jdbc.Driver jdbc.url=jdbc:mysql://localhost:3306/test jdbc.username=root jdbc.password=123456

mybatis-config.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> <properties resource="jdbc.properties"/> <environments default="development"> <environment id="development"> <transactionManager type="JDBC" /> <dataSource type="POOLED"> <property name="driver" value="${jdbc.driverClassName}" /> <property name="url" value="${jdbc.url}" /> <property name="username" value="${jdbc.username}" /> <property name="password" value="${jdbc.password}" /> </dataSource> </environment> </environments> <mappers> <mapper resource="mappers/UserMapper.xml" /> </mappers> </configuration>