Spring3.0官网文档学习笔记（六）--3.4.1

标签：学习笔记   spring3.0   官网文档   

package x.y;

public class Foo {

  public Foo(Bar bar, Baz baz) {
      // ...
  }
}

<beans>
  <bean id="foo" class="x.y.Foo">
      <constructor-arg ref="bar"/>
      <constructor-arg ref="baz"/>
  </bean>

  <bean id="bar" class="x.y.Bar"/>
  <bean id="baz" class="x.y.Baz"/>

</beans>

package examples;

public class ExampleBean {

  // No. of years to the calculate the Ultimate Answer
  private int years;

  // The Answer to Life, the Universe, and Everything
  private String ultimateAnswer;

  public ExampleBean(int years, String ultimateAnswer) {
      this.years = years;
      this.ultimateAnswer = ultimateAnswer;
  }
}

<bean id="exampleBean" class="examples.ExampleBean">
<constructor-arg type="int" value="7500000"/>
<constructor-arg type="java.lang.String" value="42"/>
</bean>

<bean id="exampleBean" class="examples.ExampleBean">
<constructor-arg index="0" value="7500000"/>
<constructor-arg index="1" value="42"/>
</bean>

<bean id="exampleBean" class="examples.ExampleBean">
<constructor-arg name="years" value="7500000"/>
<constructor-arg name="ultimateanswer" value="42"/>
</bean>

package examples;

public class ExampleBean {

  // Fields omitted

  @ConstructorProperties({"years", "ultimateAnswer"})
  public ExampleBean(int years, String ultimateAnswer) {
      this.years = years;
      this.ultimateAnswer = ultimateAnswer;
  }
}

3.4.1.3 依赖解析过程
    容器在创建之后，会对每个bean进行验证，包括验证bean引用的属性是否是有效的。但是bean引用的properties只有在bean创建之后才会被创建。单例bean在容器被创建的时候就被创建，其他的bean只有在被请求才有用到。
    Spring设置properties或者解决依赖尽可能的晚。
    A依赖于B，那么B会先被创建，然后才创建A。
3.4.1.4 DI例子
    使用静态工厂方法，传参数。
    

<bean id="exampleBean" class="examples.ExampleBean"
    factory-method="createInstance">
<constructor-arg ref="anotherExampleBean"/>
<constructor-arg ref="yetAnotherBean"/>
<constructor-arg value="1"/>
</bean>

<bean id="anotherExampleBean" class="examples.AnotherBean"/>
<bean id="yetAnotherBean" class="examples.YetAnotherBean"/>

public class ExampleBean {

  // a private constructor
  private ExampleBean(...) {
    ...
  }
  
  // a static factory method; the arguments to this method can be
  // considered the dependencies of the bean that is returned,
  // regardless of how those arguments are actually used.
  public static ExampleBean createInstance (
          AnotherBean anotherBean, YetAnotherBean yetAnotherBean, int i) {

      ExampleBean eb = new ExampleBean (...);
      // some other operations...
      return eb;
  }
}

Spring3.0官网文档学习笔记（六）--3.4.1,布布扣,bubuko.com

Spring3.0官网文档学习笔记（六）--3.4.1

标签：学习笔记   spring3.0   官网文档   

原文地址：http://blog.csdn.net/abauch_d/article/details/32935949