Spring实例化的3种方式

1、使用类构造器

applicationContext.xml

<bean id="helloBean1" class="com.yourcompany.spring.spring1.HelloBean"/>


HellBean.java

package com.yourcompany.spring.spring1;

public class HelloBean {
public void play(){
System.out.println("播放钢琴音乐1...");
}
}

Hello.java

package com.yourcompany.spring.spring1;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Hello{
public static void main(String[] args){
ApplicationContext context=new ClassPathXmlApplicationContext("applicationContext.xml");
HelloBean hello1=(HelloBean)context.getBean("helloBean1");
hello1.play();
}
}

2、使用静态工厂方法

applicationContext.xml

<bean id="helloFactory2" class="com.yourcompany.spring.spring2.HelloFactory" factory-method="createHello"/>

IHello.java

package com.yourcompany.spring.spring2;

public interface IHello {
public void play();
}

HelloFactory.java

package com.yourcompany.spring.spring2;

public class HelloFactory {
public static IHello createHello(){
return new IHello(){
public void play(){
System.out.println("播放钢琴音乐2...");
}
};
}
}

Hello.java

package com.yourcompany.spring.spring2;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Hello {
public static void main(String[] args) {
ApplicationContext context=new ClassPathXmlApplicationContext("applicationContext.xml");
IHello hello2=(IHello)context.getBean("helloFactory2");
hello2.play();
}
}

3、使用实例工厂方法

applicationContext.xml

<bean id="beanFactory" class="com.yourcompany.spring.spring3.HelloFactory" />
<bean id="helloBean3" factory-bean="beanFactory" factory-method="createHello"/>

IHello.java

package com.yourcompany.spring.spring3;

public interface IHello {
public void play();
}

HelloFactory.java

package com.yourcompany.spring.spring3;

public class HelloFactory {
public IHello createHello() {
return new IHello(){
public void play(){
System.out.println("播放钢琴音乐3...");
};
};
}
}

Hello.java

package com.yourcompany.spring.spring3;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Hello{
public static void main(String[] args){
ApplicationContext context=new ClassPathXmlApplicationContext("applicationContext.xml");
IHello hello=(IHello)context.getBean("helloBean3");
hello.play();
}
}