構(gòu)造方法和set方法的執(zhí)行順序

1. 配置文件配置如下：

    <bean id="computer" class="domain.Computer"></bean>

    <bean id="room" class="domain.Room">
        <property name="name" value="001"></property>
        <constructor-arg name="name" value="guanyu"></constructor-arg>
        <constructor-arg name="computer" ref="computer"></constructor-arg>
    </bean>

2.實(shí)體類：

public class Room {

    private String name;
    private Computer computer; //類與類關(guān)系 has a

    public Room(String name, Computer computer) {
        this.name = name;
        this.computer = computer;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Computer getComputer() {
        return computer;
    }

    public void setComputer(Computer computer) {
        this.computer = computer;
    }


    @Override
    public String toString() {
        return "Room{" +
                "name='" + name + '\'' +
                ", computer=" + computer +
                '}';
    }
}

3.測(cè)試代碼

        Room room = (Room) factory1.getBean("room");
        System.out.println(room);

4.運(yùn)行結(jié)果，展示的是set方法中的值

Room{name='001', computer=Computer{brand='null', name='null', price=null}}

5.原理：因?yàn)闃?gòu)造方法先執(zhí)行，構(gòu)造方法將值賦值為guanyu后，set方法又再次給name屬性賦值一次，將guanyu改為001

命名空間

• 本質(zhì)上就是配置文件的一種簡(jiǎn)寫
• property p:
• constructor-arg c:
  舉例：原來(lái)寫法

<bean id="room" class="domain.Room">
      <property name="name" value="001"></property>
 </bean>

簡(jiǎn)寫

<bean p:name="001"></bean>

1.配置文件中的頭部配置文件需要配置
xmlns:c="http://www.springframework.org/schema/c"

原來(lái)寫法
    <bean id="room" class="domain.Room">
        <constructor-arg name="name" value="guanyu"></constructor-arg>
        <constructor-arg name="computer" ref="computer"></constructor-arg>
    </bean>
簡(jiǎn)寫
    <bean id="room" class="domain.Room" c:name="guanyu" c:computer-ref="computer">

    </bean>

3.測(cè)試代碼

        Room room = (Room) factory1.getBean("room");
        System.out.println(room);

4.運(yùn)行結(jié)果，展示的是set方法中的值

Room{name='guanyu', computer=Computer{brand='null', name='null', price=null}}