问题:要么是因为构造方法改变了,要么就是构造方法入参实例化失败(比如没有实现) 问题 在练习spring构造器注入方式的小程序的时候报错: Exception in thread “main” org.springframework.beans.factory.BeanCreationException: Error creating bean with name ‘poeticDuke’ defined in class path resource [com/springinaction/sp…

在spark-shell中输入范例中的代码: import akka.actor.Actor import akka.actor.Props import akka.event.Logging class MyActor extends Actor { val log = Logging(context.system, this) def receive = { case "test" ⇒ log.info("received test") case _ ⇒ log…

http://czmmiao.iteye.com/blog/1480247创建一个表,含有位图index和b-tree index SQL> create table t as select object_id id ,object_name from dba_objects; Table created. SQL> create index b_tree_ind on t(id); Index created. SQL> create bitmap index b_bm_name on…

Item3:Enforce the singleton property with a private constructor or an enum type 采用枚举类型(ENUM)实现单例模式. public enum Elvis { INSTANCE; public void leaveTheBuiding(){ System.out.println("a single-element enum type is the best way to implement a singleton&q…

Newtonsoft.Json DeserializeObject 反序列化  IdentityServer4.Models Cliecnt 错误: Newtonsoft.Json.JsonSerializationException: Unable to find a constructor to use for type System.Security.Claims.Claim. A class should either have a default constructor, one co…

1.postman请求接口 http://ip:端口/index/type/_delete_by_query?conflicts=proceed body为: { "query": { "match_all": {} } } 注意,请求是POST方式. 2.curl curl -u用户名:密码 -XPOST 'ip:9200/index_name/type_name/_delete_by_query?refresh&slices=5&pretty'…

关于index_hint 在mysql查询语句中可以通过指定index_hint来告诉优化器如何使用索引,详细可以参考这里 index_hint: USE {INDEX|KEY} [FOR {JOIN|ORDER BY|GROUP BY}] ([index_list]) | IGNORE {INDEX|KEY} [FOR {JOIN|ORDER BY|GROUP BY}] (index_list) | FORCE {INDEX|KEY} [FOR {JOIN|ORDER BY|GROUP BY}…

开始看到这个错误有点匪夷所思,完全不知道问题指向哪里, 最后用过排除法,把之前建立多个类进行了一一排除,发现有个属性是 @property(nonatomic, assign) NSInteger *folderId; 解决方案: 把指针删除就可以正常编译通过了…

Principle When implement the singleton pattern please decorate the INSTANCE field with "static final" and decorate the constructor with "private". // Singleton with static factory public class Elvis { private static final Elvis INSTANC…

正确写法: @Override @SuppressWarnings("unchecked") public List<Device> queryOSDevice(String cpu){ String sql = null; if(cpu.equals("os_xp")){ sql = "from "+this.clazz.getName()+" this WHERE this.os.id = (select id from…