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目录I.环境准备1.数据库准备2.项目环境II.实例演示1.实体类,Mapper类2.注册方式2.1@MapperScan注册方式2.2@Mapper注册方式2.3MapperSca
SpringBoot项目中借助mybatis来操作数据库,对大部分java技术栈的小伙伴来说,并不会陌生;我们知道,使用mybatis,一般会有下面几个
本篇博文中主要介绍是Mapper接口与对应的xml文件如何关联的几种姿势(这个问题像不像"茴"字有几个写法😬)
使用Mysql作为本文的实例数据库,新增一张表
CREATE TABLE `money` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT,
`name` varchar(20) NOT NULL DEFAULT '' COMMENT '用户名',
`money` int(26) NOT NULL DEFAULT '0' COMMENT '钱',
`is_deleted` tinyint(1) NOT NULL DEFAULT '0',
`create_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT '创建时间',
`update_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP COMMENT '更新时间',
PRIMARY KEY (`id`),
KEY `name` (`name`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8mb4;
本文借助 springBoot 2.2.1.RELEASE + Maven 3.5.3 + idea进行开发
pom依赖如下
<dependencies>
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>2.2.0</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
</dependency>
</dependencies>
db配置信息 application.yml
spring:
datasource:
url: jdbc:mysql://127.0.0.1:3306/story?useUnicode=true&characterEncoding=UTF-8&useSSL=false&serverTimezone=Asia/Shanghai
username: root
passWord:
前面基础环境搭建完成,接下来准备下Mybatis的Entity,Mapper等基础类
数据库实体类MoneyPo
@Data
public class MoneyPo {
private Integer id;
private String name;
private Long money;
private Integer isDeleted;
private Timestamp createAt;
private Timestamp updateAt;
}
对应的Mapper接口(这里直接使用注解的方式来实现CURD)
public interface MoneyMapper {
@Options(useGeneratedKeys = true, keyProperty = "po.id", keyColumn = "id")
@Insert("insert into money (name, money, is_deleted) values (#{po.name}, #{po.money}, #{po.isDeleted})")
int save(@Param("po") MoneyPo po);
@Update("update money set `money`=#{money} where id = #{id}")
int update(@Param("id") int id, @Param("money") long money);
@Delete("delete from money where id = #{id}")
int delete(@Param("id") int id);
@Select("select * from money where id = #{id}")
@Results(id = "moneyResultMap", value = {
@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)})
MoneyPo getById(@Param("id") int id);
}
对应的Service类
@Slf4j
@Service
public class MoneyService {
@Autowired
private MoneyMapper moneyMapper;
public void basicTest() {
int id = save();
log.info("save {}", getById(id));
boolean update = update(id, 202L);
log.info("update {}, {}", update, getById(id));
boolean delete = delete(id);
log.info("delete {}, {}", delete, getById(id));
}
private int save() {
MoneyPo po = new MoneyPo();
po.setName("一灰灰blog");
po.setMoney(101L);
po.setIsDeleted(0);
moneyMapper.save(po);
return po.getId();
}
private boolean update(int id, long newMoney) {
int ans = moneyMapper.update(id, newMoney);
return ans > 0;
}
private boolean delete(int id) {
return moneyMapper.delete(id) > 0;
}
private MoneyPo getById(int id) {
return moneyMapper.getById(id);
}
}
注意,上面写完之后,若不通过下面的几种方式注册Mapper接口,项目启动会失败,提示找不到MoneyMapper对应的bean
Field moneyMapper in com.git.hui.boot.mybatis.service.MoneyService required a bean of type 'com.git.hui.boot.mybatis.mapper.MoneyMapper' that could not be found.
在配置类or启动类上,添加@MapperScan注解来指定Mapper接口的包路径,从而实现Mapper接口的注册
@MapperScan(basePackages = "com.git.hui.boot.mybatis.mapper")
@SpringBootApplication
public class Application {
public Application(MoneyService moneyService) {
moneyService.basicTest();
}
public static void main(String[] args) {
SpringApplication.run(Application.class);
}
}
执行之后输出结果如下
2021-07-06 19:12:57.984 INFO 1876 --- [ main] c.g.h.boot.mybatis.service.MoneyService : save MoneyPo(id=557, name=一灰灰blog, money=101, isDeleted=0, createAt=2021-07-06 19:12:57.0, updateAt=2021-07-06 19:12:57.0)
2021-07-06 19:12:58.011 INFO 1876 --- [ main] c.g.h.boot.mybatis.service.MoneyService : update true, MoneyPo(id=557, name=一灰灰blog, money=202, isDeleted=0, createAt=2021-07-06 19:12:57.0, updateAt=2021-07-06 19:12:57.0)
2021-07-06 19:12:58.039 INFO 1876 --- [ main] c.g.h.boot.mybatis.service.MoneyService : delete true, null
注意:
前面的@MapperScan指定mapper的包路径,这个注解则直接放在Mapper接口上
@Mapper
public interface MoneyMapper {
...
}
测试输出省略...
使用MapperScannerConfigurer来实现mapper接口注册,在很久以前,还是使用Spring的xml进行bean的声明的时候,mybatis的mapper就是这么玩的
<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
<property name="basePackage" value="xxx"/>
<property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
</bean>
对应的java代码如下:
@Configuration
public class AutoConfig {
@Bean(name = "sqlSessionFactory")
public SqlSessionFactory sqlSessionFactory(DataSource dataSource) throws Exception {
SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
bean.setDataSource(dataSource);
bean.setMapperLocations(
// 设置mybatis的xml所在位置,这里使用mybatis注解方式,没有配置xml文件
new PathMatchingResourcePatternResolver().getResources("classpath*:mapping/*.xml"));
return bean.getObject();
}
@Bean("sqlSessionTemplate")
public SqlSessionTemplate sqlSessionTemplate(SqlSessionFactory storySqlSessionFactory) {
return new SqlSessionTemplate(storySqlSessionFactory);
}
@Bean
public MapperScannerConfigurer mapperScannerConfigurer() {
MapperScannerConfigurer mapperScannerConfigurer = new MapperScannerConfigurer();
mapperScannerConfigurer.setBasePackage("com.git.hui.boot.mybatis.mapper");
mapperScannerConfigurer.setSqlSessionFactoryBeanName("sqlSessionFactory");
mapperScannerConfigurer.setSqlSessionTemplateBeanName("sqlSessionTemplate");
return mapperScannerConfigurer;
}
}
测试输出省略
本文主要介绍Mybatis中Mapper接口的三种注册方式,其中常见的两种注解方式
那么疑问来了,为啥要介绍这三种方式,我们实际的业务开发中,前面两个基本上就满足了;什么场景会用到第三种方式?
如写通用的Mapper(类似Mybatis-Plus中的BaseMapper)
如一个Mapper,多数据源的场景(如主从库,冷热库,db的操作mapper一致,但是底层的数据源不同)
工程:https://GitHub.com/liuyueyi/spring-boot-demo
源码:Https://github.com/liuyueyi/spring-boot-demo/tree/master/spring-boot/104-mybatis-ano
到此这篇关于SpringBoot+Mybatis使用Mapper接口注册的几种方式的文章就介绍到这了,更多相关SpringBoot Mapper接口注册内容请搜索编程网以前的文章或继续浏览下面的相关文章希望大家以后多多支持编程网!
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本文标题: SpringBoot+Mybatis使用Mapper接口注册的几种方式
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