对于多个item的随机概率获取

public static int itemRatio(int[] item, int[] ratio, int rand) {

if (item == null || ratio == null || item.length == 0

|| ratio.length == 0) {

return -1;

}

int sum = 0;

for (int i = 0; i < ratio.length; i++) {

if (rand >= sum && rand < sum + ratio[i]) {

return item[i];

}

sum += ratio[i];

}

return 1;

}