详解Spring Bean 之间的特殊关系

<!-- 父 Bean-->
<bean id="abstractBook" class="net.deniro.spring4.bean.Book"
   p:name="面纱" abstract="true">
</bean>
<!-- 子 Bean-->
<bean id="book1" class="net.deniro.spring4.bean.Book"
   p:press="重庆出版社" parent="abstractBook"/>
<bean id="book2" class="net.deniro.spring4.bean.Book"
   p:press="上海译文出版社" parent="abstractBook"/>

public class Settings {
  /**
   * 密码过期时间（单位：天）
   */
  public static int PASS_TIMEOUT = 30;
  /**
   * 是否开启监控
   */
  public static boolean IS_MONITOR = false;
}

public class System {
  public System() {
    init();
  }
  /**
   * 初始化
   */
  private void init() {
    //假设这些值来源于数据库
    Settings.PASS_TIMEOUT = 20;
    Settings.IS_MONITOR = true;
  }
}

public class PassManager {
  int timeout;
  public PassManager() {
    timeout = Settings.PASS_TIMEOUT;
    timerTask();
  }
  /**
   * 检测密码是否过期的定时任务
   */
  private void timerTask() {
  }
  public int getTimeout() {
    return timeout;
  }
}

<bean id="system" class="net.deniro.spring4.bean.System"/>
<bean id="manager" class="net.deniro.spring4.bean.PassManager"
   depends-on="system"/>

<bean id="author" class="net.deniro.spring4.bean.Author"/>
<bean id="book" class="net.deniro.spring4.bean.Book"
   p:authorId="author"/>

/**
 * author Bean 的 ID
 */
private String authorId;

<bean id="author10" class="net.deniro.spring4.bean.Author"/>
<bean id="book10" class="net.deniro.spring4.bean.Book"
    >
  <property name="authorId">
    <idref bean="author10"/>
  </property>
</bean>