int rangeStart = 99;
int rangeEnd = 180;

for (int i = 0; i < 100; i++) {
// 确定模
int mod = rangeEnd - rangeStart;

//生成随机数
randNum = Math.random();
// num的值会在0到mod-1,也就是0到rangeEnd - rangeStart -1
int num = ((int) (randNum * rangeEnd * 100)) % mod;

// num加rangeStart之后,值域是0到rangeEnd - 1
num += rangeStart;

if (num <= rangeStart) {
num = rangeStart + 1;
}
// 根据数据分析,这个条件不会满足,只是为了做最后的防护
if (num >= rangeEnd) {
num = rangeEnd - 1;
}
System.out.println("这次的随机数是:" + num);
}