【持久化框架MyBatis3一】MyBatis版HelloWorld

来看看

　　MyBatis这个系列的文章，主要参考《Java Persistence with MyBatis 3》。

样例数据
　　本文以MySQL数据库为例，建立一个STUDENTS表，插入两条数据，然后进行单表的增删改查

CREATE TABLE STUDENTS
(
stud_id int(11) NOT NULL AUTO_INCREMENT,
name varchar(50) NOT NULL,
email varchar(50) NOT NULL,
dob date DEFAULT NULL,
PRIMARY KEY (stud_id)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=UTF-8;
/*Sample Data for the students table */
insert into students(stud_id,name,email,dob)
values (1,'Student1','student1@gmail.com','1983-06-25');
insert into students(stud_id,name,email,dob)
values (2,'Student2','student2@gmail.com','1983-06-25');

新建Maven项目，定义pom.xml
　　 MyBatis Maven项目依赖

    <dependencies>
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.2.2</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-api</artifactId>
<version>1.7.5</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
<version>1.7.5</version>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.17</version>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
<scope>test</scope>
</dependency>
</dependencies>
 
定义MyBatis的主配置文件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="config.properties"><!--定义配置信息，在本配置中可以使用${key}来引用-->
<!--同名的key，config.properties覆盖property子元素的属性值-->
<property name="name1" value="value.in.property.element"/>
</properties>
<typeAliases>
<!--类型的别名: 用法,在resultType和parameterType可以使用别名，而不是全限定的类名-->
<typeAlias alias="Student" type="com.mybatis3.domain.Student"/>
<!--包名下的Model类，使用类名作为别名，不区分大小写-->
<package name="com.mybatis3.domain"/>
</typeAliases>
<environments default="development"><!--默认的环境信息，在生产环境中需要修改production-->
<environment id="development"><!--开发环境的配置-->
<!--事务管理，MyBatis提供了两种方式，JDBC的连接事务管理以及Managed-->
<transactionManager type="JDBC"/>
<!--数据源配置-->
<dataSource type="POOLED">
<property name="driver" value="${driver}"/>
<property name="url" value="${url}"/>
<property name="username" value="${username}"/>
<property name="password" value="${password}"/>
</dataSource>
</environment>
<environment id="production"><!--生产环境的配置-->
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<property name="driver" value="${driver}"/>
<property name="url" value="${url}"/>
<property name="username" value="${username}"/>
<property name="password" value="${password}"/>
</dataSource>
</environment>
</environments>
<mappers>
<!--SQL映射文件，可以多个-->
<mapper resource="StudentMapper.xml"/>
</mappers>
</configuration>

 
定义SQL映射配置文件Students-Mapper.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.mybatis3.mappers.StudentMapper"> <!--namespace定义的Mapper可以作为Mapper接口-->
<!--SQL列与POJO的字段的映射关系-->
<resultMap type="Student" id="StudentResult">
<id property="studId" column="stud_id"/>
<result property="name" column="name"/>
<result property="email" column="email"/>
<result property="dob" column="dob"/>
</resultMap>
<select id="findAllStudents" resultMap="StudentResult">
SELECT * FROM STUDENTS
</select>
<select id="findStudentById" parameterType="int" resultType="Student">
SELECT STUD_ID AS STUDID, NAME, EMAIL, DOB
FROM STUDENTS WHERE STUD_ID=#{Id}
</select>
<insert id="insertStudent" parameterType="student">
INSERT INTO STUDENTS(STUD_ID,NAME,EMAIL,DOB)
VALUES(#{studId },#{name},#{email},#{dob})
</insert>
</mapper>

 
定义主配置文件使用的config.properties

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/test
username=root
password=root
key=value.in.config.properties

定义Model

package com.mybatis3.domain;
import java.util.Date;
public class Student {
private Long studId;
private String name;
private String email;
private Date dob;
public Long getStudId() {
return studId;
}
public void setStudId(Long studId) {
this.studId = studId;
}
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;
}
}

定义StudentMapper接口

package com.mybatis3.mappers;
import com.mybatis3.domain.Student;
import java.util.List;
public interface StudentMapper {
List<Student> findAllStudents();
Student findStudentById(Integer id);
void insertStudent(Student student);
}

定义StudentService

package com.mybatis3.serivces;
import com.mybatis3.domain.Student;
import com.mybatis3.mappers.StudentMapper;
import com.mybatis3.util.MyBatisSqlSessionFactory;
import org.apache.ibatis.session.SqlSession;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.List;
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 {
//If sqlSession is not closed then database Connection associated this sqlSession will not be
//returned to pool and application may run out of connections.
sqlSession.close();
}
}
public Student findStudentById(Integer studId) {
logger.debug("Select Student By ID :{}", studId);
SqlSession sqlSession =
MyBatisSqlSessionFactory.openSession();
try {
StudentMapper studentMapper =
sqlSession.getMapper(StudentMapper.class);
return studentMapper.findStudentById(studId);
} finally {
sqlSession.close();
}
}
public Student findStudentById2(Integer studId) {
logger.debug("Select Student By ID :{}", studId);
SqlSession sqlSession =
MyBatisSqlSessionFactory.openSession();
try {
Student student = (Student) sqlSession.
selectOne("com.mybatis3.mappers.StudentMapper.findStudentById",
studId);
return student;
} 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();
}
}
}


单元测试

package com.mybatis3.services;
import com.mybatis3.domain.Student;
import com.mybatis3.serivces.StudentService;
import org.junit.AfterClass;
import org.junit.Assert;
import org.junit.BeforeClass;
import org.junit.Test;
import java.util.Date;
import java.util.List;
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(1);
Assert.assertNotNull(student);
System.out.println(student);
}
@Test
public void testCreateStudent() {
Student student = new Student();
Long id = 1L;
student.setStudId(id);
student.setName("student_" + id);
student.setEmail("student_" + id + "gmail.com");
student.setDob(new Date());
studentService.createStudent(student);
Student newStudent = studentService.findStudentById(id.intValue());
Assert.assertNotNull(newStudent);
}

}