具有MethodInvokingFactoryBean的PropertySourcesPlaceholderConfigurer-未解决的值

Question

I am using PropertySourcesPlaceholderConfigurer to access a file that contains 2 values : key1=value1 key2=value2.

<bean id="mainProperties"      
      class="org.springframework.context.support.PropertySourcesPlaceholderConfigurer" id="">
    <property name="locations">
        <list>
           <value>file:datafile.properties</value>
        </list>
    </property>
</bean>

values in datafile.properties are then set into system properties using MethodInvokingFactoryBean.

<bean class="org.springframework.beans.factory.config.MethodInvokingFactoryBean">
    <property name="targetObject">
        <!-- System.getProperties() -->
        <bean class="org.springframework.beans.factory.config.MethodInvokingFactoryBean">
            <property name="targetClass" value="java.lang.System" />
            <property name="targetMethod" value="getProperties" />
        </bean>
    </property>
    <property name="targetMethod" 
              value="putAll" />
    <property name="arguments">
        <!-- The new Properties -->
        <util:properties>
            <prop key="my.key1">${key1}</prop>
            <prop key="my.key2">${key2}</prop>
        </util:properties>
    </property>
</bean>

ISSUE - ${key1} & ${key2} are not resolved. I was expecting that these values will be resolved since i am loading datafile.properties using PropertySourcesPlaceholderConfigurer. Can someone please help ?

Answer 1

I am beginner in Spring. My solution is:

1. File datafile.properties :

key1=Hellow
key2=world.

2. Configuration in root-content.xml

<bean id="propertySources"
      class="org.springframework.context.support.PropertySourcesPlaceholderConfigurer">
    <property name="locations">
      <array>
        <value>/WEB-INF/jdbc.properties</value>
        <value>/WEB-INF/datafile.properties</value>
      </array>       
    </property>
</bean>

<bean id="sysProps"
      class="org.springframework.beans.factory.config.MethodInvokingFactoryBean">
    <property name="targetClass" value="java.lang.System"/>
    <property name="targetMethod" value="getProperties"/>
</bean>

<bean id="myNewProps"
      class="org.springframework.beans.factory.config.MethodInvokingFactoryBean">
    <property name="targetObject" ref="sysProps"/>
    <property name="targetMethod" value="putAll"/>
    <property name="arguments">
      <map>
        <entry key="my.key1" value="${key1}"/>
        <entry key="my.key2" value="${key2}"/>
      </map>
    </property
</bean>

3. In my central controller MainController.java :

@RequestMapping(value = "/", method = RequestMethod.GET)
public String home() {
  //...
  Properties prop = System.getProperties();
  String myKey1 = prop.getProperty("my.key1");
  String myKey2 = prop.getProperty("my.key2");

  System.out.println("\nProperties:\n my.key1 = " + myKey1 +
  "\n my.key2 = " + myKey2);
  //...
}

Console output:

Properties:
 my.key1 = Hellow
 my.key2 = world.

Note:

When using two placeholderConfigurers, may cause exception: Could not resolve placeholder 'key1' in string value "${key1}" . Each of used placeholderConfigurer must have a different placeholder.

For example:

<bean id="propertyConfigurer"
    class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
    <property name="location" value="/WEB-INF/jdbc.properties"/>        
</bean>
<!-- default placeholder ${ } -->

<bean id="propertySources"
    class="org.springframework.context.support.PropertySourcesPlaceholderConfigurer">
    <property name="locations">
      <array>    
        <value>file:datafile.properties</value>
      </array>       
    </property>
    <property name="placeholderPrefix" value="#["></property>
    <property name="placeholderSuffix" value="]"></property>        
</bean> 
<!-- placeholder #[ ] for datafile.properties -->