@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
public @interface AutoIncKey {
}

@Data
@NoArgsConstructor
@AllArgsConstructor
public class SeqInfo {

    @Id
    private String id;// 主键

    @Field
    private String collName;// 集合名称

    @Field
    private Long seqId;// 序列值

}

/**
 * 监听器用于监听Mongo Event，
 * 该类继承AbstractMongoEventListener类，
 * 因为我们需要在JAVA对象转换成数据库对象的时候操作id字段实现id自增，
 * 所以覆盖onBeforeConvert方法
 */

@Component
public class SaveEventListener extends AbstractMongoEventListener<Object> {

    @Autowired
    private MongoTemplate mongo;

    @Override
    public void onBeforeConvert(BeforeConvertEvent<Object> event) {
        final Object source = event.getSource();
        if (source != null) {
            ReflectionUtils.doWithFields(source.getClass(),new ReflectionUtils.FieldCallback(){
                @Override
                public void doWith(Field field)throws IllegalArgumentException,
                        IllegalAccessException {
                    ReflectionUtils.makeAccessible(field);
                    // 如果字段添加了我们自定义的AutoIncKey注解
                    if (field.isAnnotationPresent(AutoIncKey.class)) {
                        // 设置自增ID
                        field.set(source, getNextAutoId(source.getClass().getSimpleName()));
                    }
                }
            });
        }
    }

    /**
     * 获取下一个自增ID
     *
     * @param collName
     *            集合（这里用类名，就唯一性来说最好还是存放长类名）名称
     * @return 序列值
     */
    private Long getNextAutoId(String collName) {
        Query query = new Query(Criteria.where("collName").is(collName));
        Update update = new Update();
        update.inc("seqId", 1);
        FindAndModifyOptions options = new FindAndModifyOptions();
        options.upsert(true);
        options.returnNew(true);
        SeqInfo seq = mongo.findAndModify(query, update, options, SeqInfo.class);
        assert seq != null;
        return seq.getSeqId();
    }
}