小菜鸟学 Spring-Dependency injection(二)

注入方式一：set注入

<bean id="exampleBean" class="examples.ExampleBean">
 
<!-- setter injection using the nested <ref/> element -->
<property name="beanOne"><ref bean="anotherExampleBean"/></property>
 
<!-- setter injection using the neater 'ref' attribute -->
<property name="beanTwo" ref="yetAnotherBean"/>
<property name="integerProperty" value="1"/>
</bean>
 
<bean id="anotherExampleBean" class="examples.AnotherBean"/>
<bean id="yetAnotherBean" class="examples.YetAnotherBean"/>

public class ExampleBean {
 
  private AnotherBean beanOne;
  private YetAnotherBean beanTwo;
  private int i;
 
  public void setBeanOne(AnotherBean beanOne) {
      this.beanOne = beanOne;
  }
 
  public void setBeanTwo(YetAnotherBean beanTwo) {
      this.beanTwo = beanTwo;
  }
 
  public void setIntegerProperty(int i) {
      this.i = i;
  }
}

注入方式二：构造注入

<bean id="exampleBean" class="examples.ExampleBean">
 
<!-- constructor injection using the nested <ref/> element -->
<constructor-arg>
  <ref bean="anotherExampleBean"/>
</constructor-arg>
 
<!-- constructor injection using the neater 'ref' attribute -->
<constructor-arg ref="yetAnotherBean"/>
 
<constructor-arg type="int" value="1"/>
</bean>
 
<bean id="anotherExampleBean" class="examples.AnotherBean"/>
<bean id="yetAnotherBean" class="examples.YetAnotherBean"/>

public class ExampleBean {
 
  private AnotherBean beanOne;
  private YetAnotherBean beanTwo;
  private int i;
 
  public ExampleBean(
      AnotherBean anotherBean, YetAnotherBean yetAnotherBean, int i) {
      this.beanOne = anotherBean;
      this.beanTwo = yetAnotherBean;
      this.i = i;
  }
}

注入方式三：静态工厂方法注入

<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;
  }
}

注入方式四：自动装配