333
Spring?????????@Scope-??????-????????????-?????????
??????spring4.0??????
scope???????????????
When you create a bean definition, you create a recipe for creating actual instances of the class defined by that bean definition. The idea that a bean definition is a recipe is important, because it means that, as with a class, you can create many object instances from a single recipe.
?????????
1???singleton??????? ??
???? ??(Default) Scopes a single bean definition to a single object instance per Spring IoC container.
2???prototype??????? ??
???? ??Scopes a single bean definition to any number of object instances.
3???request???
???? ??Scopes a single bean definition to the lifecycle of a single HTTP request; that is, each HTTP request has its own instance of a bean created off the back of a single bean definition. Only valid in the context of a web-aware Spring ApplicationContext.
4???session???
???? ??Scopes a single bean definition to the lifecycle of an HTTP Session. Only valid in the context of a web-aware Spring ApplicationContext.
5???globalSession???
???? ??Scopes a single bean definition to the lifecycle of a global HTTP Session. Typically only valid when used in a Portlet context. Only valid in the context of a web-aware Spring ApplicationContext.
6???application???
???? ??Scopes a single bean definition to the lifecycle of a ServletContext. Only valid in the context of a web-aware Spring ApplicationContext.
7???websocket???
???? ??Scopes a single bean definition to the lifecycle of a ServletContext. Only valid in the context of a web-aware Spring ApplicationContext.
????????????singleton???prototype??????????????????????????????
1???spring ??????scope ??????????????????
2???@Scope("prototype")??????spring?????????controller?????????????????????????????????
3???Spring???Action????????????@Scope("prototype")?????????????????????????????????????????????Action?????????
??????????????????@Scope("singleton"),??????????????????,??????????????????????????????Action???
?? ?? ??eg????????????????????????,???????????????????????????,???????????????,??????????????????????????????,Action???????????????????????????????????????
?????????
1. singleton???????????????
???? ??singleton?????????bean?????????????????????????????????????????????????????????????????????bean????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????singleton???bean???
???? ???????????singleton?????????bean?????????????????????????????????????????????????????????????????????????????????????????????????????????????????????bean????????????????????????????????????????????????????????????????????????bean???scope???singleton?????????????????????scope???
2. prototype???????????????
???? ??scope???prototype???bean?????????????????????????????????????????????????????????????????????????????? ???????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????? ???????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????? ??????????????????????????????????????????
???? ????????????????????????????????????????????????????????????????????????????????bean???scope??????????????? prototype????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????? ?????????????????????????????????????????????????????????????????????????????????????????????????????????scope??????prototype?????????????????????prototype??? bean???????????????????????????????????????????????????????????????????????????
??
???????????????
package com.yiibai.customer.services;
public class CustomerService {
String message;
public String getMessage() {
return message;
}
public void setMessage(String message) {
this.message = message;
}
}
??
<beans xmlns="https://www.springframework.org/schema/beans"
xmlns:xsi="https://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="https://www.springframework.org/schema/beans
https://www.springframework.org/schema/beans/spring-beans-2.5.xsd">
<bean
/>
</beans>
???????????????
package com.yiibai.common;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.yiibai.customer.services.CustomerService;
public class App {
public static void main( String[] args ) {
ApplicationContext context = new ClassPathXmlApplicationContext(new String[] {"Spring-Customer.xml"});
CustomerService custA = (CustomerService)context.getBean("customerService");
custA.setMessage("Message by custA");
System.out.println("Message : " + custA.getMessage());
//retrieve it again
CustomerService custB = (CustomerService)context.getBean("customerService");
System.out.println("Message : " + custB.getMessage());
}
}
????????????
Message : Message by custA Message : Message by custA??
????????bean??????????CustomerService'???????????????????????????????????????????????custB??????????????????????????custA'????????????????????????????????????????getBean()???????????????????????????????????????Spring??IoC???????????????????????????????????????????????? getBean()???????????????????????????????????????????????????
??
<beans xmlns="https://www.springframework.org/schema/beans"
xmlns:xsi="https://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="https://www.springframework.org/schema/beans
https://www.springframework.org/schema/beans/spring-beans-2.5.xsd">
<bean
scope="prototype"/>
</beans>
??????-??????
Message : Message by custA Message : null
最后更新：2017-09-25 16:03:58