Spring之三种方法实例化Bean

1.使用构造方法实例化Bean

Bean1

public class Bean1 {
    public Bean1() {
        System.out.println("Bean.Bean");
    }
}

SpringBeans.xml

 <bean id="bean1" class="com.Learn.Class.Bean1" />

Testclass

ApplicationContext ctx=new ClassPathXmlApplicationContext("SpringBeans.xml");
        Bean1 bean1=ctx.getBean("bean1",Bean1.class);
        System.out.println("bean1 = " + bean1);

2.使用静态方法实例化Bean

Bean2

public class Bean2 {
    public Bean2(){
        System.out.println("Bean2.Bean2");
    }
}

Bean2Factory

public class Bean2Factory {
    public static Bean2 getBean2(){
        return new Bean2();

    }
}

SpringBeans.xml

 <bean id="bean2" class="com.Learn.Class.Bean2Factory" factory-method="getBean2"/>

TestClass

 ApplicationContext ctx=new ClassPathXmlApplicationContext("SpringBeans.xml");
 Bean2 bean2 = ctx.getBean("bean2",Bean2.class);
        System.out.println("bean2 = " + bean2);

 

3.使用实例方法实例化Bean

Bean3

public class Bean3 {
    public Bean3(){
        System.out.println("Bean3.Bean3");
    }
}

Bean3Factory

public class Bean3Factory {
    public  Bean3 getBean3(){
        return new Bean3();
    }
}

SprinBeans.xml

 <bean id="bean3Factory" class="com.Learn.Class.Bean3Factory" />
    <bean id="bean3" factory-bean="bean3Factory" class="com.Learn.Class.Bean3" factory-method="getBean3"/>

TestClass

 ApplicationContext ctx=new ClassPathXmlApplicationContext("SpringBeans.xml");
 Bean3 bean3 = ctx.getBean("bean3",Bean3.class);
        System.out.println("bean3 = " + bean3);