java - 在客户端/服务器应用程序中将元素添加到服务器端的 arrayList

Question

我制作了一个客户端/服务器应用程序，其中客户端迭代一些数字，并将每个数字发送到服务器。现在我想将这个数字添加到Arraylist中，但是每次包完成并启动另一个包时，第一个包中的数字就会丢失，所以我无法在服务器端保存该数字 - 有人可以帮助我吗？

这是我的客户

public class PingClientstripped {

public static void main(String[] args) throws Exception {

    String ServerName = "localhost";
    int port = 7007;
    DatagramSocket socket = new DatagramSocket();
    InetAddress IPAddress = InetAddress.getByName(ServerName);

    for (int i = 0; i < 10; i++) {
        String s = Integer.toString(i);
        DatagramPacket request = new DatagramPacket(s.getBytes(),
                s.length(), IPAddress, port);
        socket.send(request);

    }

}
// socket.close();
}

和服务器

public class PingServerstripped {

static int j = 0;
int n = 0;

public static void main(String[] args) throws Exception {
    int port = 7007;
    DatagramSocket socket = new DatagramSocket(port);
    while (true) {
        DatagramPacket request = new DatagramPacket(new byte[1024], 1024);
        socket.receive(request);
        Thread.sleep(100);
        calculation(request);

    }
}

public static void calculation(DatagramPacket request) throws IOException {
    byte[] buf = request.getData();

    ByteArrayInputStream bais = new ByteArrayInputStream(buf);
    InputStreamReader isr = new InputStreamReader(bais);
    BufferedReader br = new BufferedReader(isr);
    String receive = br.readLine();
    String line = new String(receive);

    List<String> numbers = new ArrayList<String>();
    List<String> duplicates = new ArrayList<String>();
    System.out.println("line printed" + line);
    numbers.add(line);
    System.out.println("Size of the array" + numbers.size());

    String value = null;
    for (int i = 0; i < numbers.size(); i++) {
        value = numbers.get(i);
        while (numbers.contains(value)) {
            System.out.println(i);
            duplicates.add(value);
            j++;
        }
    }

    int all = numbers.size();
    int dup = duplicates.size();
    System.out.println("final size of the array" + numbers.size());
    System.out.println("number of duplicates " + j);
    System.out.println("Those were duplicates" + dup);

   }
}

Answer 1

移动

List<String> numbers = new ArrayList<String>();
List<String> duplicates = new ArrayList<String>();

这样它们是类范围的字段而不是局部变量

例如

static int j = 0;
int n = 0;
List<String> numbers = new ArrayList<String>();
List<String> duplicates = new ArrayList<String>();

编辑

在此代码中，数字和值都没有改变，因此循环将是无限的，也许使用 if 而不是循环

     while (numbers.contains(value)) {
        System.out.println(i);
        duplicates.add(value);
        j++;
    }