如何从Java方法临时替换tomcat的deploy.properties中的属性？

Question

I have a method that consumes a rest service. The URL for this rest service is taken from deployment.properties of tomcat using org.springframework.core.env.Environment

@PropertySource("file:${catalina.home}/conf/deployment.properties")
public class OriginalService{  
    @Autowired
    private Environment env;

    public void originalMethod(){   
    String endPoint = env.getProperty("rest.url");
    .
    .
    }
}

Though I own that original service, I don't want to change anything in that project. I wish to call this method as it is from another java project but, just replace the URL in the above line, so that the method consumes my dummy service instead of original one.

Both the projects are deployed on the same tomcat server.

Is there any way I can replace the rest.url property in the deployment.properties of tomcat temporarily from a java method?

Answer 1

Rather than updating the original file, it can be altered while loading the properties. It can be done by overriding the PropertyPlaceHolderConfigurer class as follows.

public class MyPropertyConfigurer extends PropertyPlaceHolderConfigurer{
   protected void convertProperties(Properties props){
        Enumeration<?> propertyNames = props.propertyNames();
        while(propertyNames.hasMoreElements()){
          String propName = (String)propertyNames.nextElement();
          String propValue = (String)props.getProperty(propName);
          if(propName.indexOf("rest.url") != -1){
             setPropertyValue(props,propName,propValue);  
          }  
      } 
   }

   private void setPropertyValue(Properties props,String propName,String propValue){
       String newRestUrl = "<your local url>";
       props.setProperty(propName,newRestUrl);
   }
}

MyPropertyConfigurer can be registered as any other bean. I think, this is much more cleaner way.