spring学习笔记三 自动装配

地址类 Address.java

package 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;}@Overridepublic String toString() {return "Address [city=" + city + ", street=" + street + "]";}     }

车类car.java

package 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;}@Overridepublic String toString() {return "car [brand=" + brand + ", price=" + price + "]";}     }

人  person.java

package autowire;import org.omg.CosNaming.NamingContextExtPackage.AddressHelper;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;}@Overridepublic String toString() {return "person [name=" + name + ", address=" + address + ", car=" + car + "]";}    }

  
Main2.java

package autowire;import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;public class Main2 {public static void main(String[] args) {// TODO Auto-generated method stub        ApplicationContext ctx=new ClassPathXmlApplicationContext("atowire.xml");                person p=(person) ctx.getBean("person");        System.out.println(p);      }}

 

配置文件atowire.java

<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns:p="http://www.springframework.org/schema/p"xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd"><bean id="address" class="autowire.Address"p:city="BeiJing" p:street="HuiLongGuan"></bean><bean id="car" class="autowire.car" p:brand="Audi" p:price="300000"></bean><!-- <bean id="person" class="autowire.person"p:name="Tom" p:address-ref="address" p:car-ref="car"></bean> --><bean id="person" class="autowire.person"p:name="Tom" autowire="byType"></bean></beans>

运行结果：

person [name=Tom, address=Address [city=BeiJing, street=HuiLongGuan], car=car [brand=Audi, price=300000.0]]

aotowire属性指定自动装配的方式
    byName 根据bean的名字和当前的bean的setter风格的属性名进行自动匹配，若匹配不上，则不装配
    byType 根据bean当前的属性类型进行自动装配，若ioc容器中有一个以上的类型匹配，则抛异常

XML 配置里的 Bean 自动装配的缺点
•在 Bean 配置文件里设置 autowire 属性进行自动装配将会装配 Bean 的所有引用属性. 然而, 若只希望装配个别属性时, autowire 属性就不够灵活了.
•autowire 属性要么根据类型自动装配, 要么根据名称自动装配, 不能两者兼而有之.
•一般情况下，在实际的项目中很少使用自动装配功能，因为和自动装配功能所带来的好处比起来，明确清晰的配置文档更有说服力一些