移除Builders

	public static void removeBuilders(IProject project, List builderids)
			throws CoreException {
		IProjectDescription desc = project.getDescription();
		ICommand[] oldSpec = desc.getBuildSpec();
		int oldLength = oldSpec.length;
		if (oldLength == 0)
			return;
		int remaining = 0;
		// null out all commands that match the builder to remove
		for (int i = 0; i < oldSpec.length; i++) {
			if (builderids.contains(oldSpec[i].getBuilderName()))
				oldSpec[i] = null;
			else
				remaining++;
		}
		// check if any were actually removed
		if (remaining == oldSpec.length)
			return;
		ICommand[] newSpec = new ICommand[remaining];
		for (int i = 0, newIndex = 0; i < oldLength; i++) {
			if (oldSpec[i] != null)
				newSpec[newIndex++] = oldSpec[i];
		}
		desc.setBuildSpec(newSpec);
		project.setDescription(desc, IResource.NONE, null);
	}