SpringBoot系列教程Mybatis+註解整合篇

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SpringBoot系列教程Mybatis+註解整合篇

SpringBoot 系列教程 Mybatis+註解整合篇

上一篇博文介紹了 SpringBoot 整合 mybatis 的過程,但是 xml 的方式,總感覺讓人有點蛋疼;本文將介紹一種 noxml 的使用姿勢,純用註解的方式來支持 CURD

I. 環境

本文使用 SpringBoot 版本為 2.2.1.RELEASE, mybatis 版本為1.3.2,數據庫為 mysql 5+

1. 項目搭建

推薦是用官方的教程來創建一個 SpringBoot 項目; 如果直接創建一個 maven 工程的話,將下面配置內容,拷貝到你的pom.xml

  • 主要引入的是mybatis-spring-boot-starter,可以減少令人窒息的配置
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.2.1.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<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>
<pluginManagement>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</pluginManagement>
</build>
<repositories>
<repository>
<id>spring-snapshots</id>
<name>Spring Snapshots</name>
<url>https://repo.spring.io/libs-snapshot-local</url>
<snapshots>
<enabled>true</enabled>
</snapshots>
</repository>
<repository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/libs-milestone-local</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</repository>
<repository>
<id>spring-releases</id>
<name>Spring Releases</name>
<url>https://repo.spring.io/libs-release-local</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</repository>
</repositories>

2. 配置信息

application.yml 配置文件中,加一下 db 的相關配置

spring:
datasource:
url: jdbc:mysql://127.0.0.1:3306/story?useUnicode=true&characterEncoding=UTF-8&useSSL=false
username: root
password:

接下來準備一個測試表(依然借用之前 db 操作系列博文中的表結構),用於後續的 CURD;表結果信息如下

DROP TABLE IF EXISTS `money`;
CREATE TABLE `money` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT,
`name` varchar(20) NOT NULL DEFAULT '' COMMENT '用戶名',
`money` int(26) NOT NULL DEFAULT '0' COMMENT '有多少錢',
`is_deleted` tinyint(1) NOT NULL DEFAULT '0',
`create_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT '創建時間',
`update_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP COMMENT '更新時間',
PRIMARY KEY (`id`),
KEY `name` (`name`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

II. 實例整合

在前一篇的基礎上進行擴展,重點在於幹掉了 xml 文件,在 DAO 接口上通過註解來實現 CURD

1. PO

創建表對應的 PO 對象: MoneyPo

@Data
public class MoneyPo {
private Integer id;
private String name;
private Long money;
private Integer isDeleted;
private Timestamp createAt;
private Timestamp updateAt;
}

2. DAO 接口

表的操作接口,下面簡單的寫了四個接口,分別對應 CRUID 四種操作

@Mapper
public interface MoneyMapper {
// 支持主鍵寫回到po
@Options(useGeneratedKeys = true, keyProperty = "po.id", keyColumn = "id")
@Insert("insert into money (name, money, is_deleted) values (#{po.name}, #{po.money}, #{po.isDeleted})")
int savePo(@Param("po") MoneyPo po);
@Select("select * from money where name=#{name}")
@Results({@Result(property = "id", column = "id", id = true, jdbcType = JdbcType.INTEGER),
@Result(property = "name", column = "name", jdbcType = JdbcType.VARCHAR),
@Result(property = "money", column = "money", jdbcType = JdbcType.INTEGER),
@Result(property = "isDeleted", column = "is_deleted", jdbcType = JdbcType.TINYINT),
@Result(property = "createAt", column = "create_at", jdbcType = JdbcType.TIMESTAMP),
@Result(property = "updateAt", column = "update_at", jdbcType = JdbcType.TIMESTAMP)})
List<MoneyPo> findByName(@Param("name") String name);
@Update("update money set money=money+#{money} where id=#{id}")
int addMoney(@Param("id") int id, @Param("money") int money);
@Delete("delete from money where id = #{id,jdbcType=INTEGER}")
int delPo(@Param("id") int id);
@Select("<script> select * from money " +
"<trim prefix=\"WHERE\" prefixOverrides=\"AND | OR\">" +
"   <if test=\"id != null\">" +
"       id = #{id}" +
"   </if>" +
"   <if test=\"name != null\">" +
"       AND name=#{name}" +
"   </if>" +
"   <if test=\"money != null\">" +
"       AND money=#{money}" +
"   </if>" +
"</trim>" +
"</script>")
@Results({@Result(property = "id", column = "id", id = true, jdbcType = JdbcType.INTEGER),
@Result(property = "name", column = "name", jdbcType = JdbcType.VARCHAR),
@Result(property = "money", column = "money", jdbcType = JdbcType.INTEGER),
@Result(property = "isDeleted", column = "is_deleted", jdbcType = JdbcType.TINYINT),
@Result(property = "createAt", column = "create_at", jdbcType = JdbcType.TIMESTAMP),
@Result(property = "updateAt", column = "update_at", jdbcType = JdbcType.TIMESTAMP)})
List<MoneyPo> findByPo(MoneyPo po);
}

從 mapper 的實現上,也可以看出來,通過 @Insert, @Select, @Update, @Delete 四個註解來實現 CURD,使用上面這種方式時,有幾個點需要注意

  • insert: 當我們希望插入的主鍵寫回到 PO 時,可以配置@Options(useGeneratedKeys = true, keyProperty = "po.id", keyColumn = "id")
  • 動態 sql: 在註解中,通過<script>來包裝動態 sql
  • @Results 實現<resultMap>的映射關係

5. 測試

接下來簡單測試一下上面的四個接口,看是否可以正常工作

啟動類

@SpringBootApplication
public class Application {
public Application(MoneyRepository repository) {
repository.testMapper();
}
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}

測試類

@Repository
public class MoneyRepository {
@Autowired
private MoneyMapper moneyMapper;
private Random random = new Random();
public void testMapper() {
MoneyPo po = new MoneyPo();
po.setName("mybatis noxml user");
po.setMoney((long) random.nextInt(12343));
po.setIsDeleted(0);
moneyMapper.savePo(po);
System.out.println("add record: " + po);
moneyMapper.addMoney(po.getId(), 200);
System.out.println("after update: " + moneyMapper.findByName(po.getName()));
moneyMapper.delPo(po.getId());
System.out.println("after delete: " + moneyMapper.findByName(po.getName()));
}
}

輸出結果

SpringBoot系列教程Mybatis+註解整合篇

II. 其他

0. 項目

1. 一灰灰 Blog

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SpringBoot系列教程Mybatis+註解整合篇

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