Spring Jndi Context 和 PropertyPlaceholderConfigurer

Question

使用 Spring，我想读取 Webspehere 上下文中的变量。

Read a Environment Variable in Java with Websphere

在 web.xml 中定义数据....

<env-entry>
   <env-entry-name>varName</env-entry-name>
   <env-entry-value>56</env-entry-value>
   <env-entry-type>java.lang.String</env-entry-type>
</env-entry>

用java看

Context envEntryContext = (Context) new InitialContext().lookup("java:comp/env");
String mydata = (String)envEntryContext.lookup(“varName”);

但我想在我的 common.xml 中获取数据

<bean id="propertyPlaceholderConfigurer"
    class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
    <property name="locations">
        <list>
            <value>/WEB-INF/context/servweb.properties</value>
        </list>
    </property>
    <property name="ignoreUnresolvablePlaceholders">
        <value>true</value>
    </property>
</bean>

也许有类似的东西

 <constructor-arg>
     <jee:jndi-lookup jndi-name="java:comp/env" default-value="data" /> 
  </constructor-arg>

但在上下文中做同样的事情

Context envEntryContext = (Context) new InitialContext().lookup("java:comp/env");
String mydata = (String)envEntryContext.lookup(“varName”);

也许是这样的:

 <constructor-arg>
    <jee:jndi-lookup  jndi-name="java:comp/env">
      <jee:environment>
          varName=default
     </jee:environment>
  </jee:jndi-lookup>

有人知道正确的方法吗？

提前致谢

Answer 1

您可以创建自己的 PropertyPlaceholderConfigurer

public class JndiPropertyPlaceholderConfigurer extends PropertyPlaceholderConfigurer {

    private String jndiPrefix = "java:comp/env/";
    private JndiTemplate jndiTemplate = new JndiTemplate();

    @Override
    protected String resolvePlaceholder(String placeholder, Properties props) {
        String value = null;
        value = resolveJndiPlaceholder(placeholder);
        if (value == null) {
            value = super.resolvePlaceholder(placeholder, props);
        }
        return value;
    }

    private String resolveJndiPlaceholder(String placeholder) {
        try {
            String value = (String)jndiTemplate.lookup(jndiPrefix + placeholder, String.class);
            return value;
        } catch (NamingException e) {
            // ignore
        } 
        return null;
    }

    public void setJndiPrefix(String jndiPrefix) {
        this.jndiPrefix = jndiPrefix;
    }

    public void setJndiTemplate(JndiTemplate jndiTemplate) {
        this.jndiTemplate = jndiTemplate;
    }
}

然后在您的 applicationContext.xml 中使用它

<bean id="propertyPlaceholderConfigurer"
      class="mypkg.helper.JndiPropertyPlaceholderConfigurer">
    <property name="properties">
        <props>
            <prop key="varName">default</prop>
        </props>
    </property>
</bean>

或用于在属性文件中定义默认值

<bean id="propertyPlaceholderConfigurer"
      class="mypkg.helper.JndiPropertyPlaceholderConfigurer">
    <property name="location" value="classpath:/defaults.properties"/>
</bean>