时间差

long startTime = System.currentTimeMillis();
//测试时间
long endTime = System.currentTimeMillis();
long timeLong = endTime - startTime;
//long类型时间差转为double类型时间差，单位毫秒
double timeDouble= Double.parseDouble(Long.toString(timeLong));
System.out.println("时间差为 " + timeDouble+ "毫秒，即 " + timeDouble/(double)1000 + "秒");