Spring入門學習 第四節

• 自動裝配

自動裝配

1. 分別建立三個類Address.java，Car.java，Person.java
   其中Perosn類包含有Address和Car的屬性

   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. 建立相應的bean配置檔案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>
   

   在之前是通過bean的引用來給屬性賦值，現在可以使用自動裝配的方式直接賦值。

   <!-- 通過ref引用來賦值的 -->
   <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進行自動裝配
   byName根據bean的名字和當前bean的setter風格的屬性名進行自動裝配，若有匹配的則進行自動裝配，若沒有匹配的則不裝配
   byType根據bean的型別和當前bean的屬性的型別進行自動裝配,若IOC容器中有一個以上的型別匹配的bean，則丟擲異常

   <!-- 
   	可以使用autowire 屬性指定自動裝配的方式，
   	byName根據bean的名字和當前bean的setter風格的屬性名進行自動裝配，若有匹配的則進行自動裝配，若沒有匹配的則不裝配
   	byType根據bean的型別和當前bean的屬性的型別進行自動裝配,若IOC容器中有一個以上的型別匹配的bean，則丟擲異常
   -->
   <bean id="person" class="com.fafa.spring.autowire.Person"
   	p:name="Tom" autowire="byType"></bean>
   

3. 測試：
   測試方法：

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

   測試結果：

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