Spring中的自动装配

src\dayday\Person.java

package dayday;
 
/**
 * Created by I am master on 2016/11/28.
 */
public class Person {
    private String name;
    private int age;
    private City city;
    private Car car;
    public void setName(String name){
        this.name=name;
    }
    public void setAge(int age){
        this.age=age;
    }
    public void setCity(City city){
        this.city=city;
    }
    public void setCar(Car car){
        this.car=car;
    }
   public void toprint(){
       System.out.println("["+"name="+name+" age="+age+" car"+car+" city"+city+"]");
   }
}

src\daydayCity.java

package dayday;
 
/**
 * Created by I am master on 2016/11/28.
 */
public class City {
    private String livecity;
    private String street;
    public void setLivecity(String livecity) {
        this.livecity=livecity;
    }
    public void setStreet(String street{
        this.street=street;
    }
    public String getLivecity(){
        return livecity;
    }
    public String getStreet(){
        return street;
    }
    public String toString(){
        return "["+"city="+livecity+" street"+street +"]";
    }
}

src\dayday\Car.java

package dayday;
 
/**
 * Created by I am master on 2016/11/28.
 */
public class Car {
    private String name;
    public void setName(String name){
        this.name=name;
    }
    public String getName(){
        return name;
    }
    public String toString(){
        return "["+"carname="+name+"]";
    }
}

src\dayday\Main.java

package dayday;
 
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
 
/**
 * Created by I am master on 2016/11/28.
 */
public class Main {
    public static void main(String[] args){
        ApplicationContext ctx= new ClassPathXmlApplicationContext("beans.xml");
        Person person1=ctx.getBean("person1",Person.class);
        Person person2=ctx.getBean("person1",Person.class);
        person1.toprint();
        person2.toprint();
    }
}

src\beans.xml<?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 name="car" class="dayday.Car" p:name="Audi"/>
       <bean name="city" class="dayday.City" p:livecity="shaoxing" p:street="xinchang"/>
       <!--通过byType进行装配-->
       <bean name="person1" class="dayday.Person" p:name="dayday" p:age="18" autowire="byType"/>
       <!--通过byName进行装配-->
       <bean name="person2" class="dayday.Person" p:name="dayday" p:age="18" autowire="byName"/>
</beans>
运行结果

[name=dayday age=18 car[carname=Audi] city[city=shaoxing streetxinchang]]
[name=dayday age=18 car[carname=Audi] city[city=shaoxing streetxinchang]]

装配机制

byName根据bean的名字和当前bean的setter风格的属性名进行自动匹配，若有匹配的，则进行自动装配，若没有匹配的，则不装配

比如bean中有setXXX()的方法，且在配置文件中，bean中id="XXX"则可进行自动装配，id="XXX1"就不可以装配

byType根据bean的类型和当前bean的属性进行自动装配，若IOC容器中有一个及以上的类型匹配的bean，则将抛出异常

在实际开发中很少用自动装配，因为代码不够一目了然，而且存在很多局限性，如不能两种装配方式同时进行，如果选择了自动了装配，就不能手动配置...