zoukankan      html  css  js  c++  java
  • bean的singleton(没有看到生命周期范围??)

    4.5.1 The singleton scope

    Only one shared instance of a singleton bean is managed, and all requests for beans with an id or ids matching that bean definition result in that one specific bean instance being returned by the Spring container.

    To put it another way, when you define a bean definition and it is scoped as a singleton, the Spring IoC container creates exactly one instance of the object defined by that bean definition. This single instance is stored in a cache of such singleton beans(这种实例存储在这种单例beans的缓存中), and all subsequent requests and references for that named bean return the cached object.(所有后续的请求和对bean对象的引用都返回缓存的对象) 单例模式的特点

    Figure 4.2. 

    singleton

    Spring’s concept of a singleton bean differs from the Singleton pattern as defined in the Gang of Four (GoF) patterns book. The GoF Singleton hard-codes the scope of an object such that one and only one instance of a particular class is created per ClassLoader. The scope of the Spring singleton is best described as per container and per bean. This means that if you define one bean for a particular class in a single Spring container, then the Spring container creates one and only one instance of the class defined by that bean definition. The singleton scope is the default scope in Spring. To define a bean as a singleton in XML, you would write, for example:

    <bean id="accountService" class="com.foo.DefaultAccountService"/>
    
    <!-- the following is equivalent, though redundant (singleton scope is the default) -->
    <bean id="accountService" class="com.foo.DefaultAccountService" scope="singleton"/>
  • 相关阅读:
    light oj 1105 规律
    light oj 1071 dp(吃金币升级版)
    light oj 1084 线性dp
    light oj 1079 01背包
    light oj 1068 数位dp
    light oj 1219 树上贪心
    light oj 1057 状压dp TSP
    light oj 1037 状压dp
    矩阵快速幂3 k*n铺方格
    矩阵快速幂2 3*n铺方格
  • 原文地址:https://www.cnblogs.com/batman425/p/7476504.html
Copyright © 2011-2022 走看看