Bean 的配置方式

Bean 的配置方式 的三种方式：

                              ①. 通过全类名（反射）

                              ②. 通过工厂方法（静态工厂方法 & 实例工厂方法）

                              ③. FactoryBean

1.  通过全类名（反射）

package com.baidu.spring.beans.test;

public class Person {
	
	private String name;
	private int age;
	
	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 showName() {
		System.out.println("Person's name: " + name);
	}
	
}

通过全类名配置Bean

2. 通过工厂方法

Phone.java

package com.baidu._StaticFactory;

public class Phone {
	private String brand;
	private double price;

	public String getBrand() {
		return brand;
	}
	public void setBrand(String brand) {
		this.brand = brand;
	}
	public double getPrice() {
		return price;
	}
	public void setPrice(double price) {
		this.price = price;
	}
	@Override
	public String toString() {
		return "Phone [brand=" + brand + ", price=" + price + "]";
	}
	
	public Phone() {
		System.out.println("Phone`s Constructor....");
	}
	public Phone(String brand, double price) {
		super();
		this.brand = brand;
		this.price = price;
	}
}

静态工厂方法

StaticPhoneFactory.java

package com.baidu._StaticFactory;

import java.util.HashMap;
import java.util.Map;
/**
 * 静态工厂方法：直接调用某一个类的静态方法就可以返回Bean 的实例
 */
public class StaticPhoneFactory {
	
	private static Map phones = new HashMap();
	
	static {
		
		phones.put("HuaWei", new Phone( "HuaWei",4899));
		phones.put("Mi", new Phone( "Mi",1999));
	}
	//静态工厂方法
	public static Phone getPhone(String brand) {
		return phones.get(brand);
	}
}

实例工厂方法

InstanceFactory.java

package com.baidu._InstanceFactory;

import java.util.HashMap;
import java.util.Map;

import com.baidu._StaticFactory.Phone;
/**
 * 实例工厂方法：实例工厂的方法，即需要先创建工厂本身，在调用工厂的实例方法来返回bean 的实例
 */
public class InstanceFactory {
	
	private Map phones = null;
	
	public InstanceFactory() {
		phones = new HashMap();
		phones.put("HuaWei", new Phone( "HuaWei",4899));
		phones.put("Mi", new Phone( "Mi",1999));
	}
	
	public  Phone getPhone(String brand) {
		return phones.get(brand);
	}
}

配置Bean

 beans_staticefactory_instancefactory.xml

测试：

TestStaticFactoryAndInstanceFactory.java

package com.baidu._StaticFactory;

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

public class TestStaticFactoryAndInstanceFactory {
	
	public static void main(String[] args) {
		
		ApplicationContext applicationContext = new ClassPathXmlApplicationContext(" beans_staticefactory_instancefactory.xml");
		
		Phone phone1 = (Phone) applicationContext.getBean("phone1");
		System.out.println(phone1);
		
		Phone phone2= (Phone) applicationContext.getBean("phone2");
		System.out.println(phone2);
	}
}

运行结果：

Phone [brand=HuaWei, price=4899.0]
Phone [brand=Mi, price=1999.0]

3.  FactoryBean

Phone.java

package com.baidu.FactoryBean;

public class Phone {
	private String brand;
	private double price;

	public String getBrand() {
		return brand;
	}
	public void setBrand(String brand) {
		this.brand = brand;
	}
	public double getPrice() {
		return price;
	}
	public void setPrice(double price) {
		this.price = price;
	}
	@Override
	public String toString() {
		return "Phone [brand=" + brand + ", price=" + price + "]";
	}
	
	public Phone() {
		System.out.println("Phone`s Constructor....");
	}
	public Phone(String brand, double price) {
		super();
		this.brand = brand;
		this.price = price;
	}
}

PhoneFactoryBean.java

package com.baidu.FactoryBean;

import org.springframework.beans.factory.FactoryBean;
//自定义的FactoryBean 需要实现FactoryBean 接口
public class PhoneFactoryBean implements FactoryBean {
	
	//配置属性 这里只是为了演示可以这样配置
	private String brand;
	
	public void setBrand(String brand) {
		this.brand = brand;
	}

	//返回bean 的对象
	@Override
	public Phone getObject() throws Exception {
		return new Phone(brand, 4889);
	}

	//返回bean 的类型
	@Override
	public Class getObjectType() {
		return Phone.class;
	}

	//返回bean 是否为单实例
	@Override
	public boolean isSingleton() {
		return true;
	}
}

配置bean

beans_factorybean.xml

测试方法：

package com.baidu.FactoryBean;

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

public class TestSpringFactoryBean {
	
	public static void main(String[] args) {
		ApplicationContext applicationContext = new ClassPathXmlApplicationContext("beans_factorybean.xml");
		
		Phone phone = (Phone) applicationContext.getBean("phone");
		System.out.println(phone);
	}
}

运行结果：

Phone [brand=HuaWei, price=4889.0]