像这样,

Random random = new Random();
int randomNumber = random.nextInt(upperBound - lowerBound) + lowerBound;

int Random = (int)(Math.random()*100);

如果您需要生成多个值，那么只需使用 For循环

 for (int i = 1; i <= 10 ; i++)
       {
        int Random = (int)(Math.random()*100);
        System.out.println(Random);
       }

如果你想指定一个更合适的范围，比如从10到100(两者都在这个范围内)

所以代码是:

   int Random =10 +  (int)(Math.random()*(91));
   /* int Random = (min.value ) + (int)(Math.random()* ( Max - Min + 1));
  *Where min is the smallest value You want to be the smallest number possible to       
  generate and Max is the biggest possible number to generate*/

使用Random.nextInt (int)。

在你的例子中，它看起来是这样的:

a[i][j] = r.nextInt(101);

假设上界是上界，下界是下界，那么你可以在两个上界之间做一个随机数r:

int r = (int) (Math.random() * (upper - lower)) + lower;

Java不像Python那样在两个值之间有一个随机生成器。它实际上只需要一个值来生成Random。然后，您需要做的是将一个特定的数字添加到生成的数字中，这将使该数字在一个范围内。例如:

package RandGen;

import java.util.Random;

public class RandGen {


    public static Random numGen =new Random();

public static int RandNum(){
    int rand = Math.abs((100)+numGen.nextInt(100));

    return rand;
}

public static void main(String[]Args){
   System.out.println(RandNum());
}

}

This program's function lies entirely in line 6 (The one beginning with "int rand...". Note that Math.abs() simply converts the number to absolute value, and it's declared as an int, that's not really important. The first (100) is the number I am ADDING to the random one. This means that the new output number will be the random number + 100. numGen.nextInt() is the value of the random number itself, and because I put (100) in its parentheses, it is any number between 1 and 100. So when I add 100, it becomes a number between 101 and 200. You aren't actually GENERATING a number between 100 and 200, you are adding to the one between 1 and 100.

你可以用r.nextInt(101)

对于更通用的“在两个数字之间”使用:

Random r = new Random();
int low = 10;
int high = 100;
int result = r.nextInt(high-low) + low;

这将为您提供一个介于10(包含)和100(不包含)之间的随机数