本来打算写个使用Sharding-JDBC的例程，但是在搭建Mybatis的过程中，一波三折，因为好久没搭建项目了，另外加上换了电脑。所以很破折，在这里记录一下Spring Boot整合Mybatis吧。可能很简单，但是我长时间没用忘记了，我这里备忘一下吧。
一、项目目录结构
注意这里Application文件的位置，它是与controller、entity、mapper、service等包处于并列的关系。
二、数据库文件
SET NAMES utf8mb4; SET FOREIGN_KEY_CHECKS = 0; -- ---------------------------- -- Table structure for t_user_00 -- ---------------------------- DROP TABLE IF EXISTS `t_user_00`; CREATE TABLE `t_user_00` ( `id` int(0) NOT NULL AUTO_INCREMENT, `user_id` int(0) NOT NULL, `name` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL, `age` int(0) NOT NULL, PRIMARY KEY (`id`) USING BTREE ) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic; SET FOREIGN_KEY_CHECKS = 1;
三、pom.xml
<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.13.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.gougou</groupId>
<artifactId>shardingjdbc-shardingtable-demo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>shardingjdbc-shardingtable-demo</name>
<description>shardingjdbc-shardingtable-demo</description>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>1.3.2</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
四、application.yml
# 数据源 spring: application: name: shardingjdbc-shardingtable-demo datasource: url: jdbc:mysql://localhost:3306/sharding_0?serverTimezone=UTC username: root password: root driver-class-name: com.mysql.jdbc.Driver dbcp2: min-idle: 5 # 数据库连接池的最小维持连接数 initial-size: 5 # 初始化连接数 max-total: 5 # 最大连接数 max-wait-millis: 150 # 等待连接获取的最大超时时间 # mybatis配置 mybatis: mapper-locations: classpath:mapper/*.xml # mapper映射文件位置 type-aliases-package: com.gouggou.shardingtable.entity # 实体类所在的位置 configuration: log-impl: org.apache.ibatis.logging.stdout.StdOutImpl #用于控制台打印sql语句
五、启动类Application
说明：
1、@MapperScan的：扫描mapper接口的位置
2、@ComponentScan：如果Application文件的位置不是与controller、entity、mapper、service等包处于并列的关系。就要用此注解，否则可以不用；
@MapperScan("com.gouggou.shardingtable.mapper")
@SpringBootApplication
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
六、controller
@RequestMapping("student")
@RestController
public class UserController {
@Autowired
private UserService userService;
@RequestMapping("save")
public String save() {
User user = new User();
user.setUserId(new Random().nextInt( 1000 ) + 1);
user.setName("张三"+user.getUserId());
user.setAge(new Random().nextInt( 80 ) + 1);
userService.insert(user);
return user.getName()+"创建成功！";
}
}
七、service
public interface UserService {
Integer insert(User u);
List<User> findAll();
List<User> findByUserIds(List<Integer> userIds);
}
@Service
public class UserServiceImpl implements UserService {
@Autowired
private UserMapper userMapper;
@Override
public Integer insert(User u) {
return userMapper.insert(u);
}
@Override
public List<User> findAll() {
return userMapper.findAll();
}
@Override
public List<User> findByUserIds(List<Integer> userIds) {
return userMapper.findByUserIds(userIds);
}
}
八、entity
@Data
public class User implements Serializable {
private static final long serialVersionUID = -5514139686858156155L;
private Integer id;
private Integer userId;
private String name;
private Integer age;
}
九、Mapper
@Repository
public interface UserMapper {
Integer insert(User u);
List<User> findAll();
List<User> findByUserIds(List<Integer> userIds);
}
<?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.gouggou.shardingtable.mapper.UserMapper" >
<resultMap id="resultMap" type="com.gouggou.shardingtable.entity.User" >
<id column="id" property="id" jdbcType="INTEGER" />
<result column="user_id" property="userId" jdbcType="INTEGER" />
<result column="name" property="name" jdbcType="VARCHAR" />
<result column="age" property="age" jdbcType="INTEGER" />
</resultMap>
<insert id="insert">
insert into t_user_00 (user_id,name,age) values (#{userId},#{name},#{age})
</insert>
<select id="findAll" resultMap="resultMap">
select <include refid="columnsName"/> from t_user_00
</select>
<select id="findByUserIds" resultMap="resultMap">
select <include refid="columnsName"/> from t_user_00 where user_id in (
<foreach collection="list" item="item" separator=",">
#{item}
</foreach>
)
</select>
<sql id="columnsName">
id,user_id,name,age
</sql>
</mapper>
十、遇到的问题
