注解,lombok
2024-10-20 17:22:16
使用注解开发
- UserMapper
public interface UserMapper {
@Select("select * from db4.user")
List<User> getUsers();
}
- mybatis-config.xml
<mappers>
<mapper class="com.dao.UserMapper"/>
</mappers>
- test
public class test {
@Test
public void test1(){
SqlSession sqlSession = MybatisUtils.getSqlSession();
UserMapper mapper = sqlSession.getMapper(UserMapper.class);
List<User> users = mapper.getUsers();
for (User user : users) {
System.out.println(user);
}
sqlSession.close();
}
}
MybatisUtils.java自动提交事务
public class MybatisUtils {
private static SqlSessionFactory sqlSessionFactory;
static {
try {
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
} catch (IOException e) {
e.printStackTrace();
}
}
public static SqlSession getSqlSession() {
//自动提交事务
return sqlSessionFactory.openSession(true);
}
}
Lombok
说明
@Getter and @Setter
@FieldNameConstants
@ToString
@EqualsAndHashCode
@AllArgsConstructor, @RequiredArgsConstructor and @NoArgsConstructor
@Log, @Log4j, @Log4j2, @Slf4j, @XSlf4j, @CommonsLog, @JBossLog, @Flogger, @CustomLog
@Data
@Builder
@SuperBuilder
@Singular
@Delegate
@Value
@Accessors
@Wither
@With
@SneakyThrows
@val
@var
常用
@Data:无参构造,get,set,toString,hashcode,equals
@AllArgsConstructor
@NoArgsConstructor
步骤
- 安装插件
- 导入依赖
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.18.12</version>
<scope>provided</scope>
</dependency>
- 实体类上加注解
@Data
@AllArgsConstructor
@NoArgsConstructor
public class User {
private int id;
private String username;
private String pwd;
}
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