Spring入门学习（自动装配） 第四节

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自动装配

1. 分别创建三个类Address.java，Car.java，Person.java
   其中Perosn类包含有Address和Car的属性

   package com.fafa.spring.autowire;
   public class Address {
   
   	private String city;
   	private String street;
   
   	public String getCity() {
   		return city;
   	}
   
   	public void setCity(String city) {
   		this.city = city;
   	}
   
   	public String getStreet() {
   		return street;
   	}
   
   	public void setStreet(String street) {
   		this.street = street;
   	}
   
   	@Override
   	public String toString() {
   		return "Address [city=" + city + ", street=" + street + "]";
   	}
   }
   

   package com.fafa.spring.autowire;
   
   public class Car {
   
   	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 "Car [brand=" + brand + ", price=" + price + "]";
   	}
   }
   

   package com.fafa.spring.autowire;
   
   public class Person {
   
   	private String name;
   
   	private Address address;
   
   	private Car car;
   
   	public String getName() {
   		return name;
   	}
   
   	public void setName(String name) {
   		this.name = name;
   	}
   
   	public Address getAddress() {
   		return address;
   	}
   
   	public void setAddress(Address address) {
   		this.address = address;
   	}
   
   	public Car getCar() {
   		return car;
   	}
   
   	public void setCar(Car car) {
   		this.car = car;
   	}
   
   	@Override
   	public String toString() {
   		return "Person [name=" + name + ", address=" + address + ", car=" + car
   				+ "]";
   	}
   }
   

2. 创建相应的bean配置文件beans-autowire.xml

   <bean id="address" class="com.fafa.spring.autowire.Address" 
   	p:city="NanJing" p:street="QiXiaQu"></bean>
   	
   <!-- <bean id="address2" class="com.fafa.spring.autowire.Address" 
   	p:city="Dao" p:street="XuanWuQu"></bean> -->
   
   <bean id="car" class="com.fafa.spring.autowire.Car"
   	p:brand="Audi" p:price="300000"></bean>
   

   在之前是通过bean的引用来给属性赋值，现在可以使用自动装配的方式直接赋值。

   <!-- 通过ref引用来赋值的 -->
   <bean id="person" class="com.fafa.spring.autowire.Person"
   	p:name="Tom" p:address-ref="address" p:car-ref="car"></bean>
   

   Autowire可以byName或byType进行自动装配
   byName根据bean的名字和当前bean的setter风格的属性名进行自动装配，若有匹配的则进行自动装配，若没有匹配的则不装配
   byType根据bean的类型和当前bean的属性的类型进行自动装配,若IOC容器中有一个以上的类型匹配的bean，则抛出异常

   <!-- 
   	可以使用autowire 属性指定自动装配的方式，
   	byName根据bean的名字和当前bean的setter风格的属性名进行自动装配，若有匹配的则进行自动装配，若没有匹配的则不装配
   	byType根据bean的类型和当前bean的属性的类型进行自动装配,若IOC容器中有一个以上的类型匹配的bean，则抛出异常
   -->
   <bean id="person" class="com.fafa.spring.autowire.Person"
   	p:name="Tom" autowire="byType"></bean>
   

3. 测试：
   测试方法：

   @Test
   public void testPerson(){
   	ApplicationContext ctx = new ClassPathXmlApplicationContext("classpath*:beans-autowire.xml");
   	Person person = (Person) ctx.getBean("person");
   	System.out.println(person);
   }
   

   测试结果：

   Person [name=Tom, address=Address [city=NanJing, street=QiXiaQu], car=Car [brand=Audi, price=300000.0]]