Can some code run when we first deploy a WAR file?

Question

Is there any method or API that I can use so that whenever I deploy a new WAR file, a part of code should execute or perhaps when Tomcat starts, the respective servlet should s

Answer 1

i find a way to run some code only at application (*.war) deployment: it works at least for jersey servlets with java servlet using javax.ws.rs.core.Application .

The application in the file ApplicationConfig.java (see below) contains a method public getClasses which is called at application deployment. So adding code in getClasses result in having it executed at application deployment. The only caveit i noticed is that strangely this function is called twice, do not know why ,so i added a global variable in the ApplicationConfig class to know if my code has already run.

Here is my solution:

package eu.oca;

import java.util.Set;
import javax.ws.rs.core.Application;

/**                                                                                                                             
 *                                                                                                                              
 * @author mattei                                                                                                               
 */
@javax.ws.rs.ApplicationPath("jersey")
public class ApplicationConfig extends Application {

    private boolean alreadyRun = false;

    @Override
    public Set> getClasses() {

        System.out.println("Sidonie : ApplicationConfig : getClasses : alreadyRun = " + String.valueOf(alreadyRun));
        alreadyRun = true;
        Set> resources = new java.util.HashSet<>();
        addRestResourceClasses(resources);
        return resources;
    }

    /**                                                                                                                         
     * Do not modify addRestResourceClasses() method.                                                                           
     * It is automatically populated with                                                                                       
     * all resources defined in the project.                                                                                    
     * If required, comment out calling this method in getClasses().                                                            
     */
    private void addRestResourceClasses(Set> resources) {
        resources.add(eu.oca.ResultatGeneralAF.class);
        resources.add(eu.oca.ResultatGeneralF.class);
        resources.add(eu.oca.ResultatMesuresAF.class);
        resources.add(eu.oca.ResultatMesuresF.class);
        resources.add(eu.oca.SidonieAccueilD.class);
        resources.add(eu.oca.SidonieWelcomeR.class);
    }

}