面试官：小伙子，你给我说一下SpringBoot怎么整合UidG

一、基本概述

1.SpringBoot整合百度开源UidGenerator 并且替换默认的xml映射的方式为MyBatisPlus
2.SpringBoot版本为 2.2.8.RELEASE；MyBatisPlus版本为 3.3.2；UidGenerator版本为1.0.0-SNAPSHOT
3.替换默认的work_node 表结构和对应的实体类
4.替换默认的DisposableWorkerIdAssigner 并且修改注入的mapper接口为service接口

二、依赖及版本

注意事项：
由于UidGenerator 默认依赖了MyBatis 和MyBatis Spring相关依赖，在这使用的是MyBatisPlus，因此要把MyBatis 和MyBatis Spring的依赖排除。

<dependency>
    <groupId>com.baidu.fsg</groupId>
    <artifactId>uid-generator</artifactId>
    <version>${uid-generator.version}</version>
    <exclusions>
        <exclusion>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
        </exclusion>
        <exclusion>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis-spring</artifactId>
        </exclusion>
    </exclusions>
</dependency>
<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-boot-starter</artifactId>
    <version>${mybatis-plus.version}</version>
</dependency>

三、表结构及实体类替换

CREATE TABLE `sy_worker_node`  (
  `work_node_id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT '主键',
  `host_name` varchar(64)  NOT NULL COMMENT '主机名称',
  `port` varchar(64)  NOT NULL COMMENT '端口',
  `type` int(11) NOT NULL COMMENT '类型(ACTUAL or CONTAINER)',
  `launch_date` date NOT NULL COMMENT '年月日',
  `modeified` timestamp(0) NOT NULL  COMMENT '修改时间',
  `created` timestamp(0) NOT NULL  COMMENT '创建时间',
  PRIMARY KEY (`work_node_id`) USING BTREE
) ;

@TableName("sy_worker_node")
@Getter
@Setter
public class WorkNode {

    @TableId(value = "work_node_id",type = IdType.AUTO)
    private Long work_node_id;

    @TableField(value = "host_name")
    private String host_name;

    @TableField(value = "port")
    private String port;

    @TableField(value = "type")
    private Integer type;

    @TableField(value = "launch_date")
    private Date launch_date;

    @TableField(value = "modeified")
    private Date modeified;

    @TableField(value = "created")
    private Date created;

}

四、mapper接口

@Mapper
public interface WorkerNodeMapper extends BaseMapper<WorkNode>{

}

五、接口及实现类

public interface IWorkNodeService extends IService<WorkNode>{

    public WorkNode getWorkerNodeByHostPort(String host,String port);

    public void addWorkerNode(WorkNode workNode);
}

@Service("workNodeService")
public class WorkNodeServiceImpl extends ServiceImpl<WorkerNodeMapper, WorkNode> implements IWorkNodeService{

    @Override
    public WorkNode getWorkerNodeByHostPort(String host, String port) {
        QueryWrapper<WorkNode> queryWrapper=new QueryWrapper<>();
        queryWrapper.lambda().eq(WorkNode::getHost_name, host).eq(WorkNode::getPort, port);
        return getOne(queryWrapper);
    }

    @Override
    public void addWorkerNode(WorkNode workNode) {
        workNode.setCreated(new Date());
        workNode.setModeified(new Date());
        save(workNode);
    }

}

六、UidGenerator的配置类

@Configuration
public class IdGeneratorConfiguration {
    /*
        该类是在默认的基础上修改的
    */
    @Bean
    public DisposableWorkerIdAssigner disposableWorkerIdAssigner() {
        return new DisposableWorkerIdAssigner();
    }
    //默认注入的id生成器,使用时只需从容器取即可
    @Bean
    public CachedUidGenerator cachedUidGenerator() {
        CachedUidGenerator cachedUidGenerator = new CachedUidGenerator();
        cachedUidGenerator.setWorkerIdAssigner(disposableWorkerIdAssigner());
        return cachedUidGenerator;
    }

}

public class DisposableWorkerIdAssigner implements WorkerIdAssigner {
    private static final Logger LOGGER = LoggerFactory.getLogger(DisposableWorkerIdAssigner.class);
    /*
    @Autowired
    private WorkerNodeMapper workerNodeMapper;

    */
    //修改默认注入mapper为service接口
    @Autowired
    private IWorkNodeService workNodeService;

    /**
     * Assign worker id base on database.<p>
     * If there is host name & port in the environment, we considered that the node runs in Docker container<br>
     * Otherwise, the node runs on an actual machine.
     * 
     * @return assigned worker id
     */
    @Transactional
    public long assignWorkerId() {
        // build worker node entity
        WorkNode workNode = buildWorkerNode();

        // add worker node for new (ignore the same IP + PORT)
        workNodeService.addWorkerNode(workNode);
        LOGGER.info("Add worker node:" + workNode);

        return workNode.getWork_node_id();
    }

    /**
     * Build worker node entity by IP and PORT
     */
    private WorkNode buildWorkerNode() {
        WorkNode workNode = new WorkNode();
        if (DockerUtils.isDocker()) {
            workNode.setType(WorkerNodeType.CONTAINER.value());
            workNode.setHost_name(DockerUtils.getDockerHost());
            workNode.setPort(DockerUtils.getDockerPort());
            workNode.setLaunch_date(new Date());

        } else {
            workNode.setType(WorkerNodeType.ACTUAL.value());
            workNode.setHost_name(NetUtils.getLocalAddress());
            workNode.setPort(System.currentTimeMillis() + "-" + RandomUtils.nextInt(100000));
            workNode.setLaunch_date(new Date());
        }

        return workNode;
    }

}

七、测试类

@RestController
public class IndexController {
    //从容器中获取在配置类中注入的实例
    @Autowired
    private UidGenerator uidGenerator;

    @GetMapping("/index")
    public String index(){
        System.err.println(uidGenerator.getUID());
        return "success";
    }
}

测试结果：

八、总结

1. 首先要创建相关的表结构 每次启动服务会插入一条数据
2. 替换默认的DisposableWorkerIdAssigner 并且修改注入的实例
3. 在配置类中注入id的生成器及所需要的实例

最后

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