求素数

转来的 求素数：

package com.test;

public class TestS extends Thread{
	private final int number = 10000000;
	private final int nMax = (int) Math.sqrt( number);
	private final int []primeArr = new int[number+1];
	private int count;
	private double timeBegin;
	private double timeEnd;
	public void run(){
		suShu();
	}
	private void init() {
		// TODO Auto-generated method stub
		count = 0;
		for(int i=1;i<=number;i++){
			primeArr[i]=i;
		}
	}
	private void reMove(){
		for(int i=2;i<=nMax;i++){
			for(int k=i*2;k<=number;k+=i){
				primeArr[k]=0;
			}
		}
	}
	public void suShu(){
		init();
		timeBegin = System.currentTimeMillis();
		reMove();
		timeEnd = System.currentTimeMillis();
		//输出素数，并计算素数个数
		for(int i=2;i<=number;i++){
			if(primeArr[i]!=0){
				count++;
			}
		}
		System.out.println("Thread"+getId()+":"+number+"之内总共有"+count+"个素数");
		System.out.println("Thread"+getId()+":"+"查找素数总共用时"+(timeEnd-timeBegin)+"毫秒");
	}
	public static void main(String[] args) {
		new Thread(new TestS()).start();
	}
}