java - 如何查找 arraylist 是否包含类字段中的值？

Question

我有课:

static class AnotherClass {
        int number;
        String isPrime;

        public int getNumber() {
            return number;
        }

        public String getPrime() {
            return isPrime;
        }

        public void setNumber(int number) {
            this.number = number;
        }

        public void setPrime(String prime) {
            isPrime = prime;
        }

    }

在主课上我有:

    List<AnotherClass> listx = new ArrayList<AnotherClass>();//just a arraylist

for (int z = 0; z < howManyQuestions; z++) {//in loop i add class with fields
            AnotherClass classx = new AnotherClass();
            int valuex = Integer.parseInt(keyboardkey.readLine());

            classx.setNumber(valuex);//save value in this class

            String answer = Check(valuex);//i just get here string answer YES NO
            classx.setPrime(answer);

            listx.add(classx);//and i add this two fields of class to list

            System.out.println();

        }

INPUT: (i add value and check if it was input before)343OUTPUTNONOYESHow can i check if, for example value "3" is containing by list?

Answer 1

1 AnotherClass 必须实现 equals()(并相应地实现 hashCode())。

2 使用 listx 中的方法 contains(Object o)。