Java隨機生成字母數字組合的驗證碼

import java.util.Random;

public class StringRandom {

//生成隨機數字和字母,
public String getStringRandom(int length) {

String val = "";
Random random = new Random();

//參數length，表示生成幾位隨機數
for(int i = 0; i < length; i++) {

String charOrNum = random.nextInt(2) % 2 == 0 ? "char" : "num";
//輸出字母還是數字
if( "char".equalsIgnoreCase(charOrNum) ) {
//輸出是大寫字母還是小寫字母
int temp = random.nextInt(2) % 2 == 0 ? 65 : 97;
val += (char)(random.nextInt(26) + temp);
} else if( "num".equalsIgnoreCase(charOrNum) ) {
val += String.valueOf(random.nextInt(10));
}
}
return val;
}

public static void main(String[] args) {
StringRandom test = new StringRandom();
//測試
System.out.println(test.getStringRandom(8));
}
}