【MyBatis入门】—— 第一个MyBatis应用

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MyBatis学习笔记

MyBatis学习笔记

1.创建STUDENTS表并插入一些数据：

-- 创建数据库
CREATE DATABASE mybatis;
-- 使用数据库
USE mybatis;
-- 创建表
CREATE TABLE STUDENT (
	id BIGINT(20) NOT NULL AUTO_INCREMENT COMMENT 'PK',
	name VARCHAR(30) NOT NULL COMMENT '名称',
	email VARCHAR(30) NOT NULL COMMENT '邮箱',
	dob DATE DEFAULT NULL,
	PRIMARY KEY(id)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=gbk COMMENT '学生表';
-- 插入数据
INSERT INTO STUDENT(name, email, dob) VALUES('student1', 'student1@qq.com', '1990-01-01');
INSERT INTO STUDENT(name, email, dob) VALUES('student2', 'student2@qq.com', '1990-02-02');

2. 创建一个总的目录（文件夹名为mybatis-demos），用于存放所有的MyBatis应用示例

3. 打开DOS命令行窗体，进入到上面创建的文件夹mybatis-demos。使用Maven Archetype生成项目骨架：

3.1 输入命令：mvn archetype:generate

3.2 在运行到“Choose a number or apply filter (format: [groupId:]artifactId, case sensitive contains): 580:”和“Choose org.apache.maven.archetypes:maven-archetype-quickstart version:”外时直接敲回车

3.3 输入项目的groupId、artifactId、version、package，然后检查输入的groupId、artifactId、version、package信息是否正确，输入“Y”确认

使用Maven Archetype生成的项目的目录结构：

4. 修改mybatis-demo-01文件夹下的pom.xml文件，添加项目运行需要的依赖：

<dependencies>
  <dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>4.11</version>
    <scope>test</scope>
  </dependency>
  <dependency>
    <groupId>org.mybatis</groupId>
    <artifactId>mybatis</artifactId>
    <version>3.2.7</version>
  </dependency>
  <dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>5.1.22</version>
    <scope>runtime</scope>
  </dependency>
  <dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>slf4j-log4j12</artifactId>
    <version>1.7.7</version>
  </dependency>
</dependencies>

5. 在mybatis-demo-01\src\main\java\com\github\wangguocheng\mybatis\demo文件夹下新domain文件夹，然后在domain文件夹下创建Student实体类：

Student.java

package com.github.wangguocheng.mybatis.demo.domain;

import java.util.Date;

public class Student {

	private long id;
	private String name;
	private String email;
	private Date dob;
	
	public Student() {}

	public long getId() {
		return id;
	}

	public void setId(long id) {
		this.id = id;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public String getEmail() {
		return email;
	}

	public void setEmail(String email) {
		this.email = email;
	}

	public Date getDob() {
		return dob;
	}

	public void setDob(Date dob) {
		this.dob = dob;
	}
	
}

6.在mybatis-demo-01\src\main\java\com\github\wangguocheng\mybatis\demo文件夹下新建mapper文件夹，然后在mapper文件夹下创建StudentMapper类及StudentMapper.xml映射文件：

StudentMapper.java

package com.github.wangguocheng.mybatis.demo.mapper;

import java.util.List;

import com.github.wangguocheng.mybatis.demo.domain.Student;

public interface StudentMapper {
	
	public void insertStudent(Student student);

	public List<Student> findAllStudents();
	
	public Student findStudentById(long id);
}

StudentMapper.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.github.wangguocheng.mybatis.demo.mapper.StudentMapper">
  <resultMap type="Student" id="StudentResultMap">
    <id property="id" column="id"/>
    <result property="name" column="name"/>
    <result property="email" column="email"/>
    <result property="dob" column="dob"/>
  </resultMap>
  <select id="insertStudent" parameterType="Student">
    INSERT INTO STUDENT(name, email, dob)
    VALUES(#{name}, #{email}, #{dob})
  </select>
  <select id="findAllStudents" resultMap="StudentResultMap">
    SELECT * FROM STUDENT
  </select>
  <select id="findStudentById" resultMap="StudentResultMap" parameterType="long">
    SELECT * FROM STUDENT WHERE id = #{id}
  </select>
</mapper>

7. 在mybatis-demo-01\src\main文件夹下新建resources文件夹，然后在resources文件夹下创建mybatis配置文件及log4j配置文件

mybaits.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>
  <!-- 定义类型别名 -->
  <typeAliases>
    <typeAlias type="com.github.wangguocheng.mybatis.demo.domain.Student" alias="Student"/>
  </typeAliases>
  <environments default="development">
    <environment id="development">
      <transactionManager type="JDBC"/>
      <dataSource type="POOLED">
        <property name="driver" value="com.mysql.jdbc.Driver"/>
        <property name="url" value="jdbc:mysql://localhost:3306/mybatis"/>
        <property name="username" value="root"/>
        <property name="password" value="abc123"/>
      </dataSource>
    </environment>
  </environments>
  <mappers>
    <mapper resource="com/github/wangguocheng/mybatis/demo/mapper/StudentMapper.xml"/>
  </mappers>
</configuration>

log4j.properties

log4j.rootLogger=DEBUG, stdout
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d [%-5p] %c - %m%n

8. 在mybatis-demo-01\src\main\java\com\github\wangguocheng\mybatis\demo文件夹下新建util文件夹，然后在util文件夹下创建工具类

MyBatisSqlSessionFactory.java

package com.github.wangguocheng.mybatis.demo.util;

import java.io.IOException;
import java.io.InputStream;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

public class MyBatisSqlSessionFactory {

	private static SqlSessionFactory sqlSessionFactory;
	
	public static SqlSessionFactory getSqlSessionFactory() {
		if(sqlSessionFactory == null) {
			InputStream inputStream = null;
			try {
				inputStream = Resources.getResourceAsStream("mybatis.xml");
				sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
			} catch(IOException e) {
				throw new RuntimeException(e.getCause());
			}
		}
		return sqlSessionFactory;
	}
	
	public static SqlSession openSession() {
		return getSqlSessionFactory().openSession();
	}
}

9. 修改pom.xml文件，在<build>节点下添加如下代码：

<resources>
  <resource>
    <directory>src/main/java</directory>
	<includes>
	  <include>**/*.xml</include>
	</includes>
	<filtering>true</filtering>
  </resource>
  <resource>
    <directory>src/main/resources</directory>
  </resource>
</resources>

10. 在mybatis-demo-01\src\main\java\com\github\wangguocheng\mybatis\demo文件夹下新建service文件夹，然后在service文件夹下创建StudentService类

StudentService.java

package com.github.wangguocheng.mybatis.demo.service;

import java.util.List;

import org.apache.ibatis.session.SqlSession;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.github.wangguocheng.mybatis.demo.domain.Student;
import com.github.wangguocheng.mybatis.demo.mapper.StudentMapper;
import com.github.wangguocheng.mybatis.demo.util.MyBatisSqlSessionFactory;

public class StudentService {

	private Logger logger = LoggerFactory.getLogger(getClass());
	
	public List<Student> findAllStudents() {
		SqlSession sqlSession = MyBatisSqlSessionFactory.openSession();
		try {
			StudentMapper studentMapper = sqlSession.getMapper(StudentMapper.class);
			return studentMapper.findAllStudents();
		} finally {
			sqlSession.close();
		}
	}
	
	public Student findStudentById(Long id) {
		logger.debug("Select Student By ID :{}", id);
		SqlSession sqlSession = MyBatisSqlSessionFactory.openSession();
		try {
			StudentMapper studentMapper = sqlSession.getMapper(StudentMapper.class);
			return studentMapper.findStudentById(id);
		} finally {
			sqlSession.close();
		}
	}
	
	public void createStudent(Student student) {
		SqlSession sqlSession = MyBatisSqlSessionFactory.openSession();
		try {
			StudentMapper studentMapper = sqlSession.getMapper(StudentMapper.class);
			studentMapper.insertStudent(student);
			sqlSession.commit();
		} finally {
			sqlSession.close();
		}
	}
}

11. 在mybatis-demo-01\src\test\java\com\github\wangguocheng\mybatis\demo\service文件夹下新建service文件夹，然后在service文件夹下创建StudentServiceTest类

StudentServiceTest.java

package com.github.wangguocheng.mybatis.demo.service;

import java.util.Date;
import java.util.List;

import org.junit.AfterClass;
import org.junit.Assert;
import org.junit.BeforeClass;
import org.junit.Test;

import com.github.wangguocheng.mybatis.demo.domain.Student;

public class StudentServiceTest {

	private static StudentService studentService;
	
	@BeforeClass
	public static void setup() {
		studentService = new StudentService();
	}
	
	@AfterClass
	public static void tearDown() {
		studentService = null;
	}
	
	@Test
	public void testFindAllStudents() {
		List<Student> students = studentService.findAllStudents();
		Assert.assertNotNull(students);
		for(Student student : students) {
			System.out.println(student);
		}
	}
	
	@Test
	public void testFindStudentById() {
		Student student = studentService.findStudentById(1L);
		Assert.assertNotNull(student);
		System.out.println(student);
	}
	
	@Test
	public void testCreateStudent() {
		Student student = new Student();
		student.setName("new-student-02");
		student.setEmail("new-student-02@163.com");
		student.setDob(new Date());
		studentService.createStudent(student);
	}
}

12. 在DOS命令窗体中进入mybatis-demo-01文件夹，并运行命令mvn clean test