如何從applicationContext.xml中的bean讀取值？

Question

我需要在我的applicationContext.xml設置參數值接口IP地址

我讀這個設置從屬性文件我用它這種方式：

<bean id="hazelcastInterface" class="com.hazelcast.config.InterfacesConfig"> 
     <property name="interfaces"> 
      <list> 
       <value>${interface.ip_address}</value> 
      </list> 
     </property> 
     <property name="enabled" value="true" /> 
    </bean> 

現在我需要得到該值一個命令行參數。我使用Apache Commons CLI解析器，解析參數並從中創建自己的bean commandLineConf，並將其設置爲ApplicationContext。

ExternalBeanReferneceFactoryBean.setInstance("commandLineConf", conf); 
beanFactory.registerBeanDefinition(
    "commandLineConf", 
    BeanDefinitionBuilder.rootBeanDefinition(
     ExternalBeanReferneceFactoryBean.class) 
     .getBeanDefinition()); 

GenericApplicationContext rootAppContext = new GenericApplicationContext(
    beanFactory); 
rootAppContext.refresh(); 

但我不知道如何從這個bean在applicationContext.xml中獲得價值。我嘗試了很多方法，例如但它對我不起作用。

<bean id="hazelcastInterface" class="com.hazelcast.config.InterfacesConfig"> 
     <property name="interfaces"> 
      <list> 
       <value>#{commandLineConf.ipAddress}</value> 
      </list> 
     </property> 
     <property name="enabled" value="true" /> 
    </bean> 

我在做什麼錯？

Answer 1

我用適當的類測試你的XML應用程序上下文，我不得不從這個主預期的ip地址：

public static void main(String[] args) { 

     CommandLineConf conf = new CommandLineConf(); 
     conf.setIpAddress("127.0.0.1"); 
     // create root beanFactory 
     DefaultListableBeanFactory beanFactory = new DefaultListableBeanFactory(); 

     // register bean definition for the command line 
     ExternalBeanReferneceFactoryBean.setInstance("commandLineConf", conf); 
     beanFactory.registerBeanDefinition(
      "commandLineConf", 
      BeanDefinitionBuilder.rootBeanDefinition(
       ExternalBeanReferneceFactoryBean.class) 
       .getBeanDefinition()); 

     GenericApplicationContext rootAppContext = new GenericApplicationContext(
      beanFactory); 
     rootAppContext.refresh(); 

     // create the application context 
     ApplicationContext appContext = new ClassPathXmlApplicationContext(new String[] { 
      "/applicationContext.xml" 
     }, rootAppContext); 

     InterfacesConfig hazelcastInterface = (InterfacesConfig)appContext.getBean("hazelcastInterface"); 
     System.out.println(hazelcastInterface.getInterfaces().get(0)); 

    } 

所以你使用正確的語法來引用的地址，這就是：＃{commandLineConf。 ipAddress}

這讓我覺得問題出在conf變量中。你的代碼不會顯示它是如何填充的，我懷疑ipAddress是否丟失。我不能確定，因爲你沒有在你的snipplets中解析參數。 在開始構建spring上下文（即通過打印它）之前，請確保ipAddress存在於conf變量中。

我包括其餘類你可能需要有一個工作代碼：

• InterfacesConfig.java

  public class InterfacesConfig { 
      private List<String>interfaces; 
      private boolean enabled; 
  
      public List<String> getInterfaces() { 
       return interfaces; 
      } 
  
      public void setInterfaces(List<String> interfaces) { 
       this.interfaces = interfaces; 
      } 
      public boolean isEnabled() { 
       return enabled; 
      } 
  
      public void setEnabled(boolean enabled) { 
       this.enabled = enabled; 
      } 
  
  } 
  

• CommandLineConf.java

  public class CommandLineConf { 
      private String ipAddress; 
      public String getIpAddress() { 
       return ipAddress; 
      } 
  
      public void setIpAddress(String ipAddress) { 
       this.ipAddress = ipAddress; 
      } 
  } 
  

• ExternalBeanReferneceFactoryBean.java

  import java.util.HashMap; 
  import java.util.Map; 
  
  import org.springframework.beans.factory.BeanNameAware; 
  import org.springframework.beans.factory.config.AbstractFactoryBean; 
  
  public class ExternalBeanReferneceFactoryBean extends AbstractFactoryBean implements BeanNameAware { 
  
      private static Map<String, Object> instances = new HashMap<String, Object>(); 
      private String beanName; 
  
      /** 
      * @param instance the instance to set 
      */ 
      public static void setInstance(String beanName, Object instance) { 
       instances.put(beanName, instance); 
      } 
  
      @Override 
      protected Object createInstance() 
       throws Exception { 
       return instances.get(beanName); 
      } 
  
      @Override 
      public Class<?> getObjectType() { 
       return instances.get(beanName).getClass(); 
      } 
  
      @Override 
      public void setBeanName(String name) { 
       this.beanName = name; 
      } 
  
  } 
  

• 的applicationContext.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:context="http://www.springframework.org/schema/context" 
      xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd 
      http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd"> 
  <bean id="hazelcastInterface" class="com.hazelcast.config.InterfacesConfig"> 
       <property name="interfaces"> 
        <list> 
         <value>#{commandLineConf.ipAddress}</value> 
        </list> 
       </property> 
       <property name="enabled" value="true" /> 
      </bean> 
  </beans>