对于一个小型大学项目，我必须编写服务器和客户端UDP通信代码。
如果客户端发送数据而服务器只读取，一切都很好。一旦我开始从服务器向客户端发送数据，我的小程序就会出错。
public class Sensors {
private static List<Produkt> allSensors = new ArrayList<Produkt>();
public static void main(String[] args) throws Exception {
//Preparing Our Data
initSensors();
//Server Config
String serverIP = new String();
BufferedReader eingabe = new BufferedReader(new InputStreamReader(System.in));
System.out.print("IP Eintragen:");
serverIP = eingabe.readLine();
System.out.println("");
//Preparing Data to Send
try{
DatagramSocket serverSocket = new DatagramSocket(1234);
byte[] receiveData = new byte[4];
DatagramPacket receivePacket = new DatagramPacket(receiveData,
receiveData.length);
for(;;){
//Sending
for (Produkt s : allSensors) {
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
ObjectOutputStream os = new ObjectOutputStream(outputStream);
os.writeObject(s);
byte[] sendData = outputStream.toByteArray();
InetAddress ia = InetAddress.getByName(serverIP);
DatagramPacket sendPacket= new DatagramPacket(sendData,sendData.length,ia,1223);
serverSocket.send(sendPacket);
outputStream.close();
}
for (Produkt s : allSensors) {
System.out.println(s);
}
//Empfangen
try{
serverSocket.receive(receivePacket);
String sentence = new String( receivePacket.getData(), 0,
receivePacket.getLength() );
System.out.println("RECEIVED: " + sentence);
}catch(IOException e){
}
Thread.sleep(1000);
reduceValue();
}
}catch (IOException e) {
System.out.println(e);
}
}
static public void initSensors() {
allSensors.add(new Produkt("Äpfel", 0, 100, ""));
allSensors.add(new Produkt("Birnen", 0, 100, ""));
allSensors.add(new Produkt("Kiwis", 0, 100, ""));
allSensors.add(new Produkt("Bananen", 0, 100, ""));
for (Produkt s : allSensors) {
System.out.print(s.p_name + " : " + s.p_quant + "\n");
}
}
static public void reduceValue() {
for (Produkt s : allSensors) {
if (s.p_quant > 0) {
s.p_quant -= 20;
}
}
}
static public void fillValue() {
for (Produkt s : allSensors) {
s.p_quant = 100;
}
}
}
public class Fridge extends Thread {
private static int port;
private static String htmlInsert = "";
private static DataShare ds;
public Fridge(int port, DataShare ds) {
this.port = port;
this.ds = ds;
}
@Override
public void run() {
System.out.println("Start Fridge Server");
try {
handleRequest();
} catch (Exception ex) {
Logger.getLogger(Fridge.class.getName()).log(Level.SEVERE, null, ex);
}
}
static public void handleRequest() throws Exception {
try{
DatagramSocket serverSocket = new DatagramSocket(port);
byte[] recivingData = new byte[512];
DatagramPacket receivePacket = new DatagramPacket(recivingData, recivingData.length);
for(;;)
{
if(!ds.produkte.isEmpty()){
if(ds.produkte.get(0).p_quant == 0){
ds.reOrder = true;
}else{
ds.reOrder = false;
}
}
//Empfangen
serverSocket.receive(receivePacket);
//prepare Data for conversion into Produkt
recivingData = receivePacket.getData();
ByteArrayInputStream in = new ByteArrayInputStream(recivingData);
ObjectInputStream is = new ObjectInputStream(in);
Produkt reveivedProdukt = (Produkt) is.readObject();
//Decoding Produkt into DataShare
//System.out.println(reveivedProdukt);
decodeData(reveivedProdukt);
writeHTML();
//Senden
String reorder = new String();
if(ds.reOrder){
reorder = "FILL";
}else{
reorder ="NOT";
}
System.out.println(reorder);
byte[] sendingDate = reorder.getBytes("UTF-8");
DatagramPacket sendingPacket = new DatagramPacket(sendingDate, sendingDate.length,
receivePacket.getAddress(),receivePacket.getPort());
serverSocket.send(sendingPacket);
}
}catch(IOException e){
System.out.println(e);
}catch(ClassNotFoundException e){
e.printStackTrace();
}
}
static public void writeHTML() throws Exception {
List<String> lines = new ArrayList<String>(Arrays.asList("<!DOCTYPE html>\n",
"<html>\n",
" <head>\n",
" <meta charset=\"utf-8\">\n",
" <title>Test</title>\n",
" </head>\n",
" <body>\n",
"\n",
" <h1 style=\"color:red;\">Das ist ein Test</h1>\n",
"\n",
" </body>\n",
"</html>"));
htmlInsert += "<p>";
for(Produkt p : ds.produkte){
htmlInsert+= p.p_name +" Preis: " + p.p_price + " Shopname: "+
p.shop_name + " Quantity: " + p.p_quant + "</br>";
}
htmlInsert+= "</p></br>";
lines.add(6, htmlInsert);
/* WINDOWS Path file = Paths.get(".\\src\\HttpServer\\data.html");*/
/* LINUX*/ Path file = Paths.get("/home/debian/GitRepo/VSSS17/Fridge/src/HttpServer/data.html");
Files.write(file, lines, Charset.forName("UTF-8"));
}
static public void decodeData(Produkt data) {
Produkt comp = ds.getProduktByName(data.p_name);
if (!comp.p_name.equals("Fail")) {
//System.out.println("Changed" + data.p_name + "for amount: " + data.p_quant);
ds.setQuant(data.p_name, data.p_quant);
} else {
ds.addProdukt(data);
}
//System.out.println("---");
if (ds.getLegnth() != 0) {
// ds.print();
}
//System.out.println("---");
}
}
因此，一旦我从Sensordata的数量为0，我开始发送＆＃34; FILL＆＃34;字符串到我的客户端。客户只获得＆＃34; NOT＆＃34;包。这将持续大约50个包，直到客户收到＆＃34; FILL＆＃34;包。在此之后，服务器正在发送＆＃34; NOT＆＃34;包装，因为数量回到100.但客户仍然收到＆＃34; FILL＆＃34;包装再次约50包。我有不同的方法，如打开2个插座，一个用于阅读一个用于写作。但它仍然是同一个问题。
我真的不明白为什么它不起作用。无法在互联网上找到它的任何营养。也许你们可以帮助我。
答案 0 :(得分：0)
我发现了我的问题。我正在向服务器发送4 Packats。服务器正在发送4个数据包。对于我的客户端正在读取数据包的每个循环，他发送了4个新数据包并获得了4个新数据包。所以Stack of Packets刚刚增长。
我把我的客户的阅读和写作分成两个主题。现在它的工作完美