随即生成不重复的数!

[luozhangwen]

package com.lzw.test;

import java.util.ArrayList;
import java.util.List;
import java.util.Random;

public class UnSeqRandomNumber {
    private int min;
    private int max;

    public UnSeqRandomNumber() {
	this.min = 0;
	this.max = 10;
    }

    public UnSeqRandomNumber(int min, int max) {
	this();
	if (max > min) {
	    this.min = min;
	    this.max = max;
	} else
	    System.out.println("max比min小,按默认的值生成UnrepeatRandomMumber对象!");
    }

    // 第一种方法:排除法.随机生成数字,如果是新生成的数字则放到结果集中
    // 否则不采取行动
    public Integer[] getRandomA(int length) {
	if (length <= 0) {
	    System.out.println("数字长度小");
	    return new Integer[0];
	} else if (length > (this.max - this.min)) {
	    System.out.println("结果列表长度达不到要求:" + length + "结果只能是:"
		    + (this.max - this.min));
	    length = this.max - this.min;
	}
	Random rand = new Random();
	List<Integer> list = new ArrayList<Integer>();
	while (list.size() < length) {
	    Integer randnum = new Integer(this.min
		    + rand.nextInt(this.max - this.min + 1));
	    if (!list.contains(randnum)) {
		list.add(randnum);
	    }
	}
	return (Integer[]) list.toArray(new Integer[0]);
    }

    public static void outputArray(Integer[] array) {
	if (array != null) {
	    for (int i = 0; i < array.length; i++) {
		System.out.println(array[i] + " ");
	    }
	}
	System.out.println();
    }

    public static void main(String[] args) {
	// TODO Auto-generated method stub
	UnSeqRandomNumber test = new UnSeqRandomNumber(5, 35);
	outputArray(test.getRandomA(100));
    }

}