String [] s = {"sdf", "efd", "wefd", "efdd"};
        
        final String[] target = new String[3];
        
        final Random random = new Random();
        
        for(int i = 0 ; i < 3; i ++) {
                int index = random.nextInt(s.length);
            
                target[i] = s[index];
            }
        
            System.out.println(Arrays.toString(target));

------解决方案--------------------
用split数组分割法，保存到数组中，然后random,在取值