详解SpringBoot Mongo 自增长ID有序规则

< dependencies >

     < dependency >

         < groupId >org.springframework.boot</ groupId >

         < artifactId >spring-boot-starter-web</ artifactId >

     </ dependency >

     < dependency >

         < groupId >org.springframework.boot</ groupId >

         < artifactId >spring-boot-starter-data-mongodb</ artifactId >

     </ dependency >

     < dependency >

         < groupId >org.springframework.boot</ groupId >

         < artifactId >spring-boot-starter-test</ artifactId >

         < scope >test</ scope >

     </ dependency >

</ dependencies >

@Document

@Data

public class Incr {

     @Id

     private String id;

     private String collectionName;

     private Long incrId;

}

@Service

public class IncrService {

     @Autowired

     private MongoTemplate mongoTemplate;

     /**

      * 获取自增ID

      * @param collectionName

      * @return

      */

     public Long getIncrId(String collectionName){

         Query query = new Query(Criteria.where( "collectionName" ).is(collectionName));

         Update update = new Update();

         update.inc( "incrId" );

         FindAndModifyOptions options = FindAndModifyOptions.options();

         options.upsert( true );

         options.returnNew( true );

         Incr incr = mongoTemplate.findAndModify(query,update,options,Incr. class );

         return incr.getIncrId();

     }

}

@RestController

@RequestMapping (value = "incr" )

public class IncrController {

     @Autowired

     private IncrService incrService;

     @RequestMapping (value = "test" )

     public Object test(){

         long start = System.currentTimeMillis();

         List<String> aas = new ArrayList<>();

         for ( int i= 0 ;i< 10000 ;i++){

             aas.add(i+ "" );

         }

         int i = 0 ;

         aas.parallelStream().forEach(aa -> {

             incrService.getIncrId(aa+ "" );

         });

         System.out.println(System.currentTimeMillis()-start);

         return true ;

     }

}