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javaspringdependency-injectionconstructorargument

Spring does not try to inject values to constructor-arg placeholder


I have this strange problem, that Spring does not try to pass defined values to placeholder in constructor-arg. Currently it is defined as ${myProperty} , but I could write anything there, there are no errors. It just passes the literal string ${myProperty} to the bean constructor, otherwise the configuration seems to work perfectly.

My beans.xml looks like:

<?xml version="1.0" encoding="UTF-8"?>
<beans 
  xmlns="http://www.springframework.org/schema/beans"
  xmlns:context="http://www.springframework.org/schema/context"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="
    http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
    http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

  <context:property-placeholder order="1" properties-ref="propertiesBean" />

  <bean id="propertiesBean" class="org.springframework.beans.factory.config.PropertiesFactoryBean">

   <property name="properties">
      <props>
        <prop key="myProperty">Foo</prop>
      </props>
  </property>

  </bean>

  <bean id="wrapperBean" class="springapp.bean.Wrapper">    
    <constructor-arg value="${myProperty}">          
    </constructor-arg>
  </bean>

</beans>

Does anyone have an idea what I am missing with this configuration. Maybe it is something obvious, I don't have much experience with Spring. Using Spring version 3.2.x and WildFly 8.1 as a container.

EDIT:

The beans.xml is loaded like this:

public class TestServlet extends HttpServlet {
  private static final long serialVersionUID = 1L;

  private static final Log log = LogFactory.getLog(TestServlet.class);

  private XmlBeanFactory factory;

  public void init() throws ServletException {
    ClassPathResource resource = new ClassPathResource("beans.xml", TestServlet.class.getClassLoader());
    factory = new XmlBeanFactory(resource);
  }

  public void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    Wrapper bean = (Wrapper) factory.getBean("wrapperBean");
    String value = bean.inner.value;
    resp.getWriter().print(value);
  }
}

Solution

  • Your loading is flawed you should use an ApplicationContext instead of a BeanFactory.

    public class TestServlet extends HttpServlet {
      private static final long serialVersionUID = 1L;
    
      private static final Log log = LogFactory.getLog(TestServlet.class);
    
      private ApplicationContext ctx;
    
      public void init() throws ServletException {
        ctx = new ClassPathXmlApplicationContext("beans.xml");
      }
    
      public void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        Wrapper bean = ctx.getBean("wrapperBean", Wrapper.class);
        String value = bean.inner.value;
        resp.getWriter().print(value);
      }
    }
    

    For the differences check the reference guide.