void setPerspective(IWorkbenchPage page, String perspectiveId) {
  IPerspectiveRegistry registry = page.getWorkbenchWindow()
    .getWorkbench().getPerspectiveRegistry();
  page.setPerspective(registry.findPerspectiveWithId(perspectiveId));
}

    public void switchToPerspective(String perspectiveId, IWorkbenchWindow win) {
        try {
            IPerspectiveDescriptor descr = win.getWorkbench().getPerspectiveRegistry().findPerspectiveWithId(perspectiveId);
            if (descr == null) {
                log.error("Cannot find perspective ID "+perspectiveId);
                return;
            }
            IPerspectiveDescriptor currentPersp = win.getActivePage().getPerspective();
            if (currentPersp.getId().equals(perspectiveId)) {
                return;
            }
            win.getWorkbench().showPerspective(perspectiveId, win);
        } catch (WorkbenchException ex) {
            log.error("", ex);
        }
    }