A Bean definition contains the following piece of information called configuration metadata, which helps the container know the following things.<\/p>\n
\u2022 The way a bean should be created.
\n\u2022 Life cycle details of a bean.
\n\u2022 Associated Bean dependencies.<\/p>\n
The above metadata for the bean configuration is provided as a set of properties or attributes in an XML file (configuration file) which together prepare a bean definition. The following are the set of properties.<\/p>\n
| Properties<\/th>\n | Usage<\/th>\n<\/tr>\n\n |
|---|---|
| class<\/td>\n | In a bean definition, it is a mandatory attribute. It is used to specify the bean class which can be used by the container to create the bean.<\/td>\n<\/tr>\n |
| name<\/td>\n | In a bean definition, this attribute is used to specify the bean identifier uniquely. In XML based configuration metadata for a bean, we use the id and\/or name attributes in order to specify the bean identifier(s).<\/td>\n<\/tr>\n |
| scope<\/td>\n | This attribute is used to specify the scope of the objects which are created from a particular bean definition.<\/td>\n<\/tr>\n |
| constructor-arg<\/td>\n | In a bean definition, this attribute is used to inject the dependencies.<\/td>\n<\/tr>\n |
| properties<\/td>\n | In a bean definition, this attribute is used to inject the dependencies.<\/td>\n<\/tr>\n |
| autowiring mode<\/td>\n | In a bean definition, this attribute is used to inject the dependencies.<\/td>\n<\/tr>\n |
| lazy-initialization mode<\/td>\n | In a bean definition, a lazy-initialized bean informs the IoC container to create a bean instance only when it is first requested, instead of startup.<\/td>\n<\/tr>\n |
| initialization method<\/td>\n | In a bean definition, a callback to be called after all required properties on the bean have been set up by the container.<\/td>\n<\/tr>\n |
| destruction method<\/td>\n | In a bean definition, a callback to be used when the container that contains the bean is destroyed.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n In the following example, we are going to look into an XML based configuration file which has different bean definitions. The definitions include lazy initialization (lazy-init), initialization method (init-method), and destruction method (destroy-method) as shown below. This configuration metadata file can be loaded either through BeanFactory or ApplicationContext <\/p>\n \r\n<?xml version = "1.0" encoding = "UTF-8"?>\r\n\r\n<beans xmlns = "http:\/\/www.springframework.org\/schema\/beans"\r\n xmlns:xsi = "http:\/\/www.w3.org\/2001\/XMLSchema-instance"\r\n xsi:schemaLocation = "http:\/\/www.springframework.org\/schema\/beans\r\n http:\/\/www.springframework.org\/schema\/beans\/spring-beans-3.0.xsd">\r\n\r\n <!-- A simple bean definition -->\r\n <bean id = "..." class = "...">\r\n <!\u2014 Here will be collaborators and configuration for this bean -->\r\n <\/bean>\r\n\r\n <!-- A bean definition which has lazy init set on -->\r\n <bean id = "..." class = "..." lazy-init = "true">\r\n <!-- Here will be collaborators and configuration for this bean -->\r\n <\/bean>\r\n\r\n <!-- A bean definition which has initialization method -->\r\n <bean id = "..." class = "..." init-method = "...">\r\n <!-- Here will be collaborators and configuration for this bean -->\r\n <\/bean>\r\n\r\n <!-- A bean definition which has destruction method -->\r\n <bean id = "..." class = "..." destroy-method = "...">\r\n <!-- collaborators and configuration for this bean go here -->\r\n <\/bean>\r\n\r\n <!-- more bean definitions can be written below -->\r\n \r\n<\/beans>\r\n<\/pre>\n","protected":false},"excerpt":{"rendered":" |