android java获取随机数
String
获取 x 位 由0到9组成的随机字符串。
调用方法
java
Log.i("lxh", "获取由数字0到9组成的随机字符串:" + getStr(12));
函数
java
public String RandomStr(int length) {
String characters = "0123456789";
Random random = new Random();
StringBuilder sb = new StringBuilder(length);
for (int i = 0; i < length; i++) {
int randomIndex = random.nextInt(characters.length());
char randomChar = characters.charAt(randomIndex);
sb.append(randomChar);
}
return sb.toString();
}
private static Set<String> stringSet = new HashSet<>();
public boolean isRepeat(String str) {
if (stringSet.size() >= 10000) {
stringSet.clear();
}
if (!stringSet.contains(str)) {
stringSet.add(str);
return true;
}
return false;
}
public String getStr(int length) {
String back = "";
while (true) {
String ss = RandomStr(length);
Log.d("TAG", "rs=" + ss);
if (isRepeat(ss)) {
back = ss;
break;
}
}
return back;
}
未完待续...
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