Generating a number between 1 and 2 java Math.random() with a probability set for each number

I'm trying to generate a random numbers between 1 and 2 using the imported math.random() class and set the probability for each number.

The code below set the probability to be 1/2 for the two number each 1/2

int randomInt = (Math.random() <= 0.5) ? 1 : 2;

I want to be able to set the probability for each individual numbers, for example number 1 (20% probability) and number 2 (80% probability) or the ratio of 20:80. any solution?

Edit : the programme i need to make is be able to set the probability for number 1 and number 2 separately. like asking the user to input the probability for number 1 and 2