面试官：小伙子，你给我说一下SpringBoot怎么整合UidGenerator吧

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。

	com.baidu.fsg
	uid-generator
	${uid-generator.version}
	
		
			org.mybatis
			mybatis
		
		
			org.mybatis
			mybatis-spring
		
	


	com.baomidou
	mybatis-plus-boot-starter
	${mybatis-plus.version}

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{

}

五、接口及实现类

public interface IWorkNodeService extends IService{

	public WorkNode getWorkerNodeByHostPort(String host,String port);

	public void addWorkerNode(WorkNode workNode);
}

@Service("workNodeService")
public class WorkNodeServiceImpl extends ServiceImpl implements IWorkNodeService{

	@Override
	public WorkNode getWorkerNodeByHostPort(String host, String port) {
		QueryWrapper 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.

     * If there is host name & port in the environment, we considered that the node runs in Docker container

     * 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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