【备战春招】第18天 Spring入门

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课程名称：Spring入门

课程章节：第2章 Spring Bean作用域

课程讲师：西昆仑

课程内容：

一、自定义作用域

1、自定义作用域

代码示例：

//MyScope.class
public class MyScope implements Scope {
Map<String, Object> map1 = new ConcurrentHashMap<String, Object>();
Map<String, Object> map2 = new ConcurrentHashMap<String, Object>();
//获取一个实例
public Object get(String name, ObjectFactory<?> objectFactory){
if(!map1.containsKey(name)){
Object o = objectFactory.getObject();
map1.put(name, o);
return o;
}
if(!map2.containsKey(name)){
Object o = objectFactory.getObject();
map2.put(name, o);
return o;
}
int i = new Random().nextInt(2);
if(i==0){
return map1.get(name);
}else{
return map2.get(name);
}
}
//移除一个实例
@Nullable
public Object remove(String name){
if(map2.containsKey(name)){
Object o = map2.get(name);
map2.remove(name);
return o;
}
if(map1.containsKey(name)){
Object o = map1.get(name);
map1.remove(name);
return o;
}
return null;
}
}

//spring.xml
<bean class="com.imooc.spring.ioc.class09.MyScope" id="myScope"/>
<bean class="org.springframework.beans.factory.config.CustomScopeConfigurer">
<property name="scopes">
<map>
<entry key="myScope" value-ref="myScope"/>
</map>
</property>
</bean>
<bean id="bean" class="com.imooc.spring.ioc.class009.Bean" scope="myScope"/>

//Class009Test.class
public void test(){
ApplicationContext context = new ClassPathXmlApplicationContext("spring.xml");
for(int i=0;i<10;i++){
Bean bean = context.getBean("bean",Bean.class);
System.out.println("bean="+bean);
}
}

运行结果：

2、SimpleThreadScope

//spring.xml
<bean class="com.imooc.spring.ioc.class09.MyScope" id="myScope"/>
<bean class="org.springframework.context.support.SimpleThreadScope" id="simpleThreadScope"/>
<bean class="org.springframework.beans.factory.config.CustomScopeConfigurer">
<property name="scopes">
<map>
<entry key="myScope" value-ref="myScope"/>
<entry key="simpleThreadScope" value-ref="simpleThreadScope"/>
</map>
</property>
</bean>
<bean id="bean" class="com.imooc.spring.ioc.class009.Bean" scope="myScope"/>

//Class009Test.class
public void test(){
ApplicationContext context = new ClassPathXmlApplicationContext("spring.xml");
for(int i=0;i<10;i++){
Bean bean = context.getBean("bean",Bean.class);
System.out.println("bean="+bean);
}
for(int i=0;i<10;i++){
new Thread(new Runnable() {
public void Run(){
Bean bean = context.getBean("bean",Bean.class);
System.out.println("bean="+bean);
}
})
}
}