java - 使用 xml 配置不会禁用 Autowiring

Question

尽管给 bean 的 autowire-candidate 属性设置了 false 值，它们还是会被 Autowiring 。无法找到我所缺少的东西。

Color.java

package org.manya.autowire;

public class Color {

    private String color;

    public void setColor(String color)
    {
        this.color = color;
    }

    public String getColor()
    {
        return this.color;
    }

    public String toString()
    {
        return this.color;
    }
}

Engine.java

package org.manya.autowire;

public class Engine {
    private String engine;

    public void setEngine(String engine)
    {
        this.engine = engine;
    }

    public String getEngine()
    {
        return engine;
    }

    public String toString()
    {
        return this.engine;
    }
}

Car.java

package org.manya.autowire;

public class Car {
    private Color color;
    private Engine engine;
    public Color getColor() {
        return color;
    }
    public void setColor(Color color) {
        System.out.println("From the setter of Color in org.manya.innerBean.Car");
        this.color = color;
    }
    public Engine getEngine() {
        return engine;
    }
    public void setEngine(Engine engine) {
        System.out.println("From the setter of Engine in org.manya.innerBean.Car");
        this.engine = engine;
    }

    public String toString()
    {
        return "This car has, engine : " + this.engine + ", color : " + this.color;
    }
}

autowire.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 id="car" class="org.manya.autowire.Car" autowire="byName"
     />

    <bean name="color" class="org.manya.autowire.Color" autowire-candidate="false">
        <property name="color">
            <value>Grey</value> 
        </property> 
    </bean> 

    <bean id="engine" class="org.manya.autowire.Engine" autowire-candidate="false"
    p:engine="v10"  
    />

</beans>

In autowire.xml i have declared car as autowired by name, but both of its dependencies i have declared as autowire-candidate as false. So this code should have given me an Exception. But when i am running it, Car is getting instantiated. What am i missing here?

Answer 1

根据这个Spring JIRA ticket autowire-candidate="false" 仅影响基于类型的 Autowiring 尝试，不会影响按名称的直接引用...也不会影响 autowire="byName"。

While the latter may be debatable, I'm not inclined to change it at this point since autowire="byName" is an outdated mechanism to begin with. I'm therefore turning this into a documentation issue.