Yes, war can result in lasting peace, if nations are rebuilt and strong governments are put in place. An example of this would be post World War Two Germany. The United States built up the economy, and put a strong government in place that was then able to sustain itself. The two countries have worked together quite well ever since.
The thing is that people who make war, wants more war and it won't stop. It will keep going and world peace will impossible to make. Everyday we wonder if we can make the world better, we can but we can't make the world perfect. Even if you try with all you heart there will be war, there will be conflict, there will be struggles, but we can be for help to make the world stronger.
No. War will never create a lasting peace. War often creates peace through force, which really isn't peace at all. Peace through force is only tyrannical leadership of the opposing country's military forces. The people of the invaded country will never know true peace when someone else is running their government.