spring容器中bean的作用域bean的后处理器

容器bean中的作用域

applicationcontext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

<!-- 注册Service，
scope="prototype" 原型模式，其对象的创建时机不是在Spring容器初始化时创建，而是在代码中真正访问时才创建
scope="singleton" 单例模式，其对象的创建时机是在Spring容器初始化时创建，是默认值
-->
<bean id="myService" class="com.bjpowernode.ba04.SomeServiceImpl" scope="singleton"/>

</beans>接口：
public interface ISomeService {
void doSome();
}

工厂类：

public class ServiceFactory {
public static ISomeService getSomeService() {
return new SomeServiceImpl();
}
}

实现类：

public class SomeServiceImpl implements ISomeService {
private int a;

public SomeServiceImpl() {
System.out.println("执行无参构造器");
}

/*
public SomeServiceImpl(int a) {
this.a = a;
}
*/

@Override
public void doSome() {
System.out.println("执行doSome()方法");
}

}测试类
public class MyTest {

@Test
public void test01() {
// 创建容器对象，加载Spring配置文件
String resource = "com/bjpowernode/ba03/applicationContext.xml";
ApplicationContext ac = new ClassPathXmlApplicationContext(resource);
ISomeService service = (ISomeService) ac.getBean("myService");
service.doSome();
}

}


后处理器：
applicationcontext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

<!-- 注册Service -->
<bean id="myService" class="com.bjpowernode.ba05.SomeServiceImpl"/>
<bean id="myService2" class="com.bjpowernode.ba05.SomeServiceImpl"/>

<!-- 注册Bean后处理器 -->
<bean class="com.bjpowernode.ba05.MyBeanPostProcessor"/>

</beans>

处理器类：
通过处理改变输出字母的大小写

public class MyBeanPostProcessor implements BeanPostProcessor {

// bean：表示当前正在进行初始化的Bean对象
// beanName：表示当前正在进行初始化的Bean对象的id
@Override
public Object postProcessBeforeInitialization(Object bean, String beanName)
throws BeansException {
System.out.println("执行 ----before---()方法");
return bean;
}

@Override
public Object postProcessAfterInitialization(final Object bean, String beanName)
throws BeansException {
System.out.println("执行 ----after---()方法");
if ("myService".equals(beanName)) {
Object obj = Proxy.newProxyInstance(bean.getClass()
.getClassLoader(), bean.getClass().getInterfaces(),
new InvocationHandler() {

@Override
public Object invoke(Object proxy, Method method,
Object[] args) throws Throwable {
Object invoke = method.invoke(bean, args);
if ("doSome".equals(method.getName())) {
return ((String) invoke).toUpperCase();
}
return invoke;
}
});
return obj;
}
return bean;
}

}

接口类
public interface ISomeService {
String doSome();
String doOther();
}实现类
public class SomeServiceImpl implements ISomeService {

@Override
public String doSome() {
System.out.println("执行doSome()方法");
return "abcde";
}

@Override
public String doOther() {
System.out.println("执行doOther()方法");
return "fghig";
}

}


测试类：
public class MyTest {

@Test
public void test01() {
// 创建容器对象，加载Spring配置文件
String resource = "com/bjpowernode/ba05/applicationContext.xml";
ApplicationContext ac = new ClassPathXmlApplicationContext(resource);

ISomeService service = (ISomeService) ac.getBean("myService");
System.out.println(service.doSome());
System.out.println(service.doOther());

System.out.println("======================");

ISomeService service2 = (ISomeService) ac.getBean("myService2");
System.out.println(service2.doSome());
System.out.println(service2.doOther());
}

}