spring-framework-中文文档三:依赖注入DI

public class SimpleMovieLister {

  // the SimpleMovieLister has a dependency on a MovieFinder
  private MovieFinder movieFinder;

  // a constructor so that the Spring container can 'inject' a MovieFinder
  public SimpleMovieLister(MovieFinder movieFinder) {
      this.movieFinder = movieFinder;
  }

  // business logic that actually 'uses' the injected MovieFinder is omitted...
}

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;
  }
}

public class SimpleMovieLister {

  // SimpleMovieLister对MovieFinder有依赖性
  private MovieFinder movieFinder;

  //一个setter方法，以便Spring容器可以'注入'一个MovieFinder
  public void setMovieFinder(MovieFinder movieFinder) {
      this.movieFinder = movieFinder;
  }

  //实际“使用”注入的MovieFinder的业务逻辑被省略。
}

<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;
  }
}

<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;
  }
}

<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;
  }
}

<bean id="myDataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">

<!-- results in a setDriverClassName(String) call -->
<property name="driverClassName" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/mydb"/>
<property name="username" value="root"/>
<property name="password" value="masterkaoli"/>
</bean>

<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="myDataSource" class="org.apache.commons.dbcp.BasicDataSource"
      destroy-method="close"
      p:driverClassName="com.mysql.jdbc.Driver"
      p:url="jdbc:mysql://localhost:3306/mydb"
      p:username="root"
      p:password="masterkaoli"/>

</beans>

<bean id="mappings"
    class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">

 <!-- typed as a java.util.Properties -->
 <property name="properties">
    <value>
       jdbc.driver.className=com.mysql.jdbc.Driver
       jdbc.url=jdbc:mysql://localhost:3306/mydb
    </value>
 </property>
</bean>

<bean  id = “theTargetBean”  class = “...” />

<bean  id = “theClientBean”  class = “...” > 
  <property  name = “targetName” > 
      <idref  bean = “theTargetBean” /> 
  </ property> 
</ bean>

<bean  id = “theTargetBean”  class = “...” />

<bean  id = “client”  class = “...” > 
  <property  name = “targetName”  value = “theTargetBean” /> 
</ bean>

<property  name = “targetName” > 
 <！ - 一个ID为'theTargetBean'的bean必须存在; 否则会抛出异常 - >
  <idref  local = “theTargetBean” /> 
</ property>

<ref  bean = “someBean” />

<ref  local = “someBean” />

<！ - 在父上下文中 - >
 <bean  id = “accountService”  class = “com.foo.SimpleAccountService” > 
  <！ - 根据需要插入依赖关系 - >
 </ bean>



<！ - 在子（后代）上下文中 - >
 <bean  id = “accountService”   < -  bean名称与父bean相同 - >
    类= “的org.springframework.aop.framework.ProxyFactoryBean”>
    <property  name = “target” > 
        <ref  parent = “accountService” />   <！ - 注意我们如何引用父bean  - >
     </ property> 
  <！ - 根据需要插入其他配置和依赖关系 - >
 </ bean>

<bean  id = “outer”  class = “...” > 
<！ - 而不是使用对目标bean的引用，只需定义目标bean inline  - >
 <property  name = “target” > 
  <bean  class = “com.example.Person” >  <！ - 这是内部bean  - >
     <property  name = “name”  value = “Fiona Apple” /> 
    <property  name = “age”  value = “25” /> 
  < / bean> 
</ property> 
</ bean>

<bean  id = “moreComplexObject”  class = “example.ComplexObject” > 
<！ - 导致setAdminEmails（java.util.Properties）调用 - >
 <property  name = “adminEmails” > 
  <props> 
      <prop  key = “管理员“ > administrator@example.org </ prop> 
      <prop  key = ”support“ > support@example.org </ prop> 
      <prop  key = ”development“ > development@example.org </ prop>
  </ props> 
</ property>
<！ - 产生一个setSomeList（java.util.List）调用 - >
 <property  name = “someList” > 
  <list> 
      <value>一个列表元素，后跟一个引用 </ value> 
      <ref  bean = “myDataSource “ /> 
  </ list> 
</ property> 
<！ - 导致setSomeMap（java.util.Map）调用 - >
 <property  name = ”someMap“ > 
  <map> 
      <entry  key = ”entry“  value = “只是一些字符串” /> 
      <entry  key = “a ref”  value-ref = “myDataSource”/> 
  </ map> 
</ property> 
<！ - 导致setSomeSet（java.util.Set）调用 - >
 <property  name = “someSet” > 
  <set> 
      <value>只是一些字符串</ value> 
      <ref  bean = “myDataSource” /> 
  </ set> 
</ property> 
</ bean>

<beans>
<bean id="parent" abstract="true" class="example.ComplexObject">
  <property name="adminEmails">
      <props>
          <prop key="administrator">administrator@example.com</prop>
          <prop key="support">support@example.com</prop>
      </props>
  </property>
</bean>
<bean id="child" parent="parent">
  <property name="adminEmails">
      <!-- the merge is specified on the *child* collection definition -->
      <props merge="true">
          <prop key="sales">sales@example.com</prop>
          <prop key="support">support@example.co.uk</prop>
      </props>
  </property>
</bean>
<beans>