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我正在使用以下代码从Applet客户端与java套接字进行连接。我在下面的代码中将addNewClient()函数中发生的每个NEW连接中存储了客户端的IP地址和一些随机数。我将此信息存储在HashMap中。我在HashMap的ArrayList中添加更多客户信息。HashMap数据不会将新数据附加到ArrayList中
如果ArrayList已经有客户信息了，我需要仔细阅读。我在SocketConnection课程中使用Iterator来尝试。
我看到的问题是，我将3个客户端信息添加到ArrayList。但是，当我使用Iterator来读取它时，它只能获得最后添加的客户端信息，而其他KEYS只是变空了。但是，在同一时间，它正确地给ArrayList的大小为3
请问有些专家请参考我的下面的完整代码，并告诉我什么可能是在那里的问题？
public class DataSharingSocketListner {
public static void main(String[] args) {
System.out.println("client trying to connect before thread creation");
Thread thr = new Thread(new SocketThread());
thr.start();
}
}
class SocketThread implements Runnable {
HashMap<String, ClientInfo> clientInfo = new HashMap<String, ClientInfo>();
ArrayList<HashMap<String, ClientInfo>> myList = new ArrayList<HashMap<String, ClientInfo>>();
@Override
public void run() {
try {
System.out.println("client trying to connect after thread creation");
ServerSocket server = new ServerSocket(8080);
while (true) {
SocketConnection client = new SocketConnection(server.accept(), clientInfo, myList);
client.start();
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
class SocketConnection extends Thread {
InputStream input;
PrintWriter output;
Socket socket;
ObjectOutputStream out = null;
OutputStream clientOutput;
Scanner scannerObj;
HashMap<String, byte[]> hm;
InetAddress addr;
HashMap<String, ClientInfo> clientinfo;
ArrayList<HashMap<String, ClientInfo>> clientList;
public SocketConnection(Socket socket, HashMap<String, ClientInfo> clientInfo, ArrayList<HashMap<String, ClientInfo>> myList) {
super("Thread 1");
this.socket = socket;
//this.hm = dataHashMap;
this.clientinfo = clientInfo;
this.clientList = myList;
try {
// IT IS PRINTING TOTAL SIZE 3 SUCCESSFULLY HERE
int totalClientList = clientList.size();
System.out.println("totalClientList: " + totalClientList);
if (totalClientList>0)
{
for (int i=0; i<totalClientList; i++)
{
System.out.println("client list reading " + i);
HashMap<String, ClientInfo> tmpData = (HashMap<String, ClientInfo>) clientList.get(i);
// IT IS GETTING ONLY THE LAST KEY, OTHER KEYS ARE SHOWING EMPTY
Set<String> key = tmpData.keySet();
Iterator it = key.iterator();
while (it.hasNext()) {
System.out.println("hasNexthasNext");
String hmKey = (String)it.next();
ClientInfo hmData = (ClientInfo) tmpData.get(hmKey);
System.out.println("Key: "+hmKey +" & Data: "+hmData.getRandomNo());
it.remove(); // avoids a ConcurrentModificationException
}
}
// TO ADD NEW CLIENT EVERY TIME
addNewClient();
}
else {
System.out.println("Client List shows empty");
// TO ADD NEW CLIENT EVERY TIME
addNewClient();
}
// Not used yet, will be used
input = socket.getInputStream();
scannerObj = new Scanner(socket.getInputStream());
clientOutput = socket.getOutputStream();
} catch (IOException e) {
e.printStackTrace();
}
}
public int genRandomNumber() {
Random r = new Random(System.currentTimeMillis());
return 10000 + r.nextInt(20000);
}
String getLocalIP() {
InetAddress inetAddress = null;
String ipAddress = null;
try {
inetAddress = InetAddress.getLocalHost();
ipAddress = inetAddress.getHostAddress();
} catch (UnknownHostException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println("ipAddress : " + ipAddress);
return ipAddress;
}
void addNewClient() {
String ipAddress = getLocalIP();
if (ipAddress!=null)
{
ClientInfo clientobj = new ClientInfo();
clientobj.setIPAdd(ipAddress);
int randno = genRandomNumber();
System.out.println("genRandomNumber() : " + randno);
clientobj.setRandomNo(randno);
String key = String.valueOf(randno);
clientinfo.put(key, clientobj);
clientList.add(clientinfo);
}
}
@Override
public void run() {
System.out.println("Going to Read client data");
//do something
{
String hostIP = addr.getHostAddress() ;
System.out.println("hostIP: " + hostIP);
//do something
}
}
}
class ClientInfo {
private String IPAddress;
private long RandomNumber;
private byte[] data;
public static void main(String []args) {
System.out.println("Client info Main");
}
//Setter
void setIPAdd (String ip) {
System.out.println("setIPAdd called");
IPAddress = ip;
}
void setRandomNo (long randomno) {
RandomNumber = randomno;
}
void setImageData (byte[] imgData) {
data = imgData;
}
//Getter
String getIPAdd() {
return IPAddress;
}
long getRandomNo() {
return RandomNumber;
}
byte[] getImageData() {
return data;
}
}
更新：按照Amrish的建议，更改了下面的代码，它解决了这个问题。
int totalClientList = clientList.size();
System.out.println("totalClientList: " + totalClientList);
if (totalClientList>0)
{
for (int i=0; i<totalClientList; i++)
{
System.out.println("client list reading " + i);
HashMap<String, ClientInfo> tmpData = (HashMap<String, ClientInfo>) clientList.get(i);
Set<String> key = tmpData.keySet();
System.out.println("key: " + key);
}
addNewClient();
}
else {
System.out.println("Client List shows empty");
addNewClient();
}
void addNewClient() {
String ipAddress = getLocalIP();
if (ipAddress!=null)
{
// CREATE NEW OBJECT EVERY TIME WHEN STORING
HashMap<String, ClientInfo> clientInfo = new HashMap<String, ClientInfo>();
ClientInfo clientobj = new ClientInfo();
//System.out.println("Test log 1" + clientobj);
clientobj.setIPAdd(ipAddress);
// System.out.println("Test log 2");
int randno = genRandomNumber();
System.out.println("genRandomNumber() : " + randno);
clientobj.setRandomNo(randno);
String key = String.valueOf(randno);
//System.out.println("key: " + key);
clientInfo.put(key, clientobj);
clientList.add(clientInfo);
}
}
我尝试添加HashMap对象分别为每个时间商店，但也观察到同样的问题。 – Stella
好吧，阿姆里什，你发现问题很完美！每次存储时我都尝试添加新的hasmap对象，现在它会正确列出所有项目。 – Stella
我现在更新了修改的工作代码。 – Stella