bean的实例化

bean的实例化

   构造器方式

   静态方法方式

   普通工厂方式

 

一般的，默认bean实例化使用的是构造器方式，调用的是无参的构造方法

package com.Model;

public class Dog {
    private String name;
    private int age;
    
    public Dog(){
        System.out.println("初始化Dog类");
    }
    public Dog(String name,int age){
        this.name=name;
        this.age=age;
        System.out.println("这是有参数的构造方法");
    }
    public void shou(){
        System.out.println("旺旺");
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    

}
public void testContext(){
        ApplicationContext ac=
            new ClassPathXmlApplicationContext("com/test/applicationContext.xml");
        Dog dog=(Dog) ac.getBean("dog");
        dog.shou();
        //System.out.println(dog.getName()+"\t"+dog.getAge());
    }

配置让spring容器调用参构造方法，需要在application.xml的对应bean里面配置

<bean id="dog" class="com.Model.Dog" >
        <constructor-arg index="0" value="阿旺"></constructor-arg>
        <constructor-arg index="1" value="5"></constructor-arg>
</bean>

@Test
    public void testContext(){
        ApplicationContext ac=
            new ClassPathXmlApplicationContext("com/test/applicationContext.xml");
        Dog dog=(Dog) ac.getBean("dog");
        dog.shou();
        System.out.println(dog.getName()+"\t"+dog.getAge());
    }