//现在时间的TIMESTAMP

long epoch = System.currentTimeMillis()/1000;

//某一时间的TIMESTAMP

Calendar c = Calendar.getInstance();

c.setTime(....);

c.getTimeInMillis()/1000;

Calendar c = Calendar.getInstance();

c.set(2010,3,11); //注意此处,应该是3不是4

c.getTimeInMillis()/1000;