Maven项目整合Mybatis
2021-02-21
预计阅读时间：3分钟
下面详细记录下Maven项目整合Mybatis的详细步骤：
- 在IDEA中开始界面选择“New Project”
- 左侧项目类型选择“Maven”，右侧选择jdk版本，这里不选取项目模板来进行全新创建
- 填写项目名称、GroupId、ArtifactId，选择项目存储位置后点击“Finish”
- 创建项目完成后，继续完成下面的项目结构
src
└ main
└ java
└ mapper
StudentMapper.java
└ pojo
Student.java
└ service
StudentService.java
└ Impl
StudentServiceImpl.java
└ util
DataBaseUtil.java
└ resources
└ mappers
StudentMaper.xml
MyBatisConfig.xml
jdbc.properties
└ test
└ java
MybatisTest.java
pom.xml
pom.xml——引入项目依赖：
<?xml version="1.0" encoding="UTF-8"?>
<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/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.devon</groupId>
<artifactId>mybatis_quiz</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>jar</packaging>
<properties>
<maven.compiler.source>8</maven.compiler.source>
<maven.compiler.target>8</maven.compiler.target>
</properties>
<dependencies>
<!-- https://mvnrepository.com/artifact/org.mybatis/mybatis -->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.6</version>
</dependency>
<!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.28</version>
</dependency>
<!-- https://mvnrepository.com/artifact/junit/junit -->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.13.1</version>
<scope>test</scope>
</dependency>
<!-- 开启lombok -->
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.18.24</version>
<optional>true</optional>
</dependency>
</dependencies>
</project>
StudentMapper.java——定义Mapper接口方法：
package mapper;
import pojo.Student;
import java.util.List;
public interface StudentMapper {
List<Student> getList();
}
Student.java——定义实体类：
package pojo;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
@Data
@AllArgsConstructor
@NoArgsConstructor
public class Student {
private Integer number;
private String name;
private String sex;
private Integer age;
private String dept;
}
StudentService.java——定义service层接口方法，与mapper层同名：
package service;
import pojo.Student;
import java.util.List;
public interface StudentService {
List<Student> getList();
}
StudentServiceImpl.java——定义service接口实现类：
package service.impl;
import mapper.StudentMapper;
import org.apache.ibatis.session.SqlSession;
import pojo.Student;
import service.StudentService;
import util.DataBaseUtil;
import java.util.List;
public class StudentServiceImpl implements StudentService {
@Override
public List<Student> getList() {
List<Student> students = null;
SqlSession session = DataBaseUtil.getSqlSession();
StudentMapper stumapper = session.getMapper(StudentMapper.class);
students = stumapper.getList();
return students;
}
}
DataBaseUtil.java——定义数据库连接工具类：
package util;
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;
public class DataBaseUtil {
private static SqlSessionFactory sqlSessionFactory;
private DataBaseUtil(){};
public static SqlSession getSqlSession(){
try {
//加载核心配置文件
InputStream resourceAsStream = Resources.getResourceAsStream("MyBatisConfig.xml");
if (sqlSessionFactory == null){
//获取SqlSessionFactoryBuilder
SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();
//将获得的 SqlSessionFactory 对象赋给初始化的对象 sqlSessionFactory
sqlSessionFactory = sqlSessionFactoryBuilder.build(resourceAsStream);
}
//获取SqlSession
SqlSession sqlSession = sqlSessionFactory.openSession();
return sqlSession;
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
}
StudentMaper.xml——绑定与mapper接口对应的SQL语句：
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"https://mybatis.org/dtd/mybatis-3-mapper.dtd">
<!--注意：这里的 namespace 属性需要填写上面 mapper 接口的全类名-->
<mapper namespace="mapper.StudentMapper">
<select id="getList" resultType="pojo.Student">
select * from student
</select>
</mapper>
MyBatisConfig.xml——Mybatis核心配置文件：
<?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>
<!-- 数据库属性文件 -->
<properties resource="jdbc.properties"></properties>
<!-- 环境配置时主体内容 -->
<environments default="development">
<environment id="development">
<!-- 单独使用时配置成 MANAGED 没有事务 -->
<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>
<!--加载映射文件，注意这个是XML文件，路径使用“/”,而不是包使用com.bjwl.mapper-->
<mappers>
<mapper resource="mappers/StudentMapper.xml"/>
</mappers>
</configuration>
MybatisTest.java——测试service接口是否正常：
import org.junit.Test;
import pojo.Student;
import service.impl.StudentServiceImpl;
import java.util.List;
public class MybatisTest {
@Test
public void studentTest(){
StudentServiceImpl studentService = new StudentServiceImpl();
List<Student> list = studentService.getList();
if(list != null){
for (int i = 0; i < list.size(); i++) {
System.out.println(list.get(i).toString());
}
}
}
}
完成上述编码，执行测试类，执行结果如下：
另：jdbc.properties（可选）
driver=com.mysql.cj.jdbc.Driver
url=jdbc:mysql://<IP>:3306/<databaseName>?serverTimezone=GMT%2b8
username=<username>
password=<password>
附：student 表建表 SQL 语句
-- ----------------------------
-- Table structure for student
-- ----------------------------
DROP TABLE IF EXISTS `student`;
CREATE TABLE `student` (
`number` int(10) unsigned NOT NULL AUTO_INCREMENT,
`name` varchar(100) NOT NULL,
`sex` varchar(10) NOT NULL,
`age` int(11) NOT NULL,
`dept` varchar(100) NOT NULL,
PRIMARY KEY (`number`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8;
-- ----------------------------
-- Records of student
-- ----------------------------
BEGIN;
INSERT INTO `student` (`number`, `name`, `sex`, `age`, `dept`) VALUES (1, '张三', '男', 21, '初三（1）班');
INSERT INTO `student` (`number`, `name`, `sex`, `age`, `dept`) VALUES (2, '李四', '女', 22, '高三（4）班');
INSERT INTO `student` (`number`, `name`, `sex`, `age`, `dept`) VALUES (3, '李娜', '女', 18, '高一（1）班');
INSERT INTO `student` (`number`, `name`, `sex`, `age`, `dept`) VALUES (4, '王强', '男', 19, '高三（10）班');
COMMIT;