while循环：

int number1 = 0;
int loop = 6;

while (loop > 0){
    number1 += (int) (Math.random () * 6 + 1);
    loop--;
}

for循环：

int number1 = 0;
int loop = 6;

for (int i = 0; i < loop; i++){
    number1 += (int) (Math.random() * 6 + 1);
}

您可以只使用一个变量编写更简单的解决方案：

for(int i = 0; i <= 6){
    number += (int) (Math.random () * 6 + 1);
}

方法1-使用do while循环

int sum =0;
do{
    sum += (int) (Math.random () * 6 + 1);
  }while(sum < 100);
System.out.println("Sum = " + sum);

方法2-使用while循环

int sum =0;
while(sum < 100){
     sum += (int) (Math.random () * 6 + 1);
}
System.out.println("Sum = " + sum);

方法3-使用for循环

int sum;
for(sum = 0; sum < 100;){
    sum += (int) (Math.random () * 6 + 1);
}
System.out.println("Sum = " + sum);

有很多方法可以做到这一点。一个简单的方法是使用一个无限循环，当 number1 == 100 . 检查也很重要 if (number1 > 100) 在添加一个随机数之后，如果 true .

public class Main {
    public static void main(String[] args) {
        int number1 = 0;
        while (true) {
            System.out.println("Current value: " + number1);
            if (number1 == 100) {
                break;
            }
            int random = (int) (Math.random() * 6 + 1);
            number1 += random;
            if (number1 > 100) {
                number1 -= random;
            }
        }
    }
}

示例运行：

Current value: 0
Current value: 4
Current value: 9
Current value: 13
Current value: 19
Current value: 24
Current value: 29
Current value: 35
Current value: 39
Current value: 43
Current value: 48
Current value: 51
Current value: 57
Current value: 58
Current value: 62
Current value: 66
Current value: 70
Current value: 74
Current value: 79
Current value: 85
Current value: 88
Current value: 93
Current value: 97
Current value: 97
Current value: 98
Current value: 98
Current value: 100

避免将生成的随机数 int ，我建议您使用 Random#nextInt(int bound) 如下图所示：

import java.util.Random;

public class Main {
    public static void main(String[] args) {
        int number1 = 0;
        Random rand = new Random();
        while (true) {
            System.out.println("Current value: " + number1);
            if (number1 == 100) {
                break;
            }
            int random = rand.nextInt(6) + 1;
            number1 += random;
            if (number1 > 100) {
                number1 -= random;
            }
        }
    }
}

一个简单的for循环就可以了。您没有指定何时结束，因此下面是一个运行10次迭代的示例：

int number1 = 0;
for(int i = 0; i < 10; ++i) {
    number1 += (int)(Math.random() * 6 + 1);
}

您还可以随机选择：

int number1 = 0;
Random random = new Random();
for(int i = 0; i < 10; ++i) {
    number1 += random.nextInt(6) + 1;
}