<分区>
在这里，我设法在单个服务器和单个客户端之间建立连接，但现在我的新障碍是如何在 Java 客户端实现 TCP 连接池。我浏览了很多站点，但最终没有找到有效的解决方案。这是我用来获取与服务器的连接的类:
public class TCPIPCommunicator {
private final String MODULE="TCPIPCommunicator :";
//private DeviceEntity deviceEntity;
private static InetAddress inetServer = null;
private static int devicePort = -1;
private Socket clientSocket;
private BufferedOutputStream outputStream;
private BufferedInputStream inputStream;
private static boolean isLinkActive = false;
private String IP="";
public TCPIPCommunicator(String IP, int devicePort) {
this.IP=IP;
this.devicePort=devicePort;
initialize();
}
public static boolean isLinkActive(){
return isLinkActive;
}
public static void setLinkStatus(boolean status){
isLinkActive = status;
}
private void initialize() {
System.out.println(MODULE+ "Inside initialize()" );
setLinkStatus(false);
try{
inetServer = InetAddress.getByName(IP);
}catch (UnknownHostException uhe) {
System.out.println(MODULE+ "Error while creating inetaddress, Reason:"+uhe.getMessage());
}
System.out.println(MODULE+ "Connecting to - " +inetServer.getHostAddress() + ":" + devicePort);
establishConnection();
if(!isLinkActive()){
//sendNotification(TCPIPConstants.LINK_DOWN);
releaseResources();
//resumeLinkSanityHelper();
}
System.out.println(MODULE+ "out of initialize(), isLinkActive :" + isLinkActive() );
}
public boolean establishConnection(){
boolean isConnected = false;
//Get the Connection to PMS Server.
if(inetServer != null && devicePort > 0){
try{
clientSocket = new Socket(inetServer, devicePort);
clientSocket.setKeepAlive(true);
}catch(ConnectException ce){
ce.printStackTrace();
setLinkStatus(false);
System.out.println(MODULE+ "Exception in initialize() " + "Couldnot Connect Server. Reason:"+ce.getMessage());
}catch(Exception e){
e.printStackTrace();
setLinkStatus(false);
System.out.println(MODULE+ "Exception in initialize() " + "while creating socket ,Reason: " + e.getMessage());
}
//If got connection, Get the streams.
if(clientSocket != null && !clientSocket.isClosed()){
System.out.println(MODULE+ "in initialize(), Got Socket Connection." );
try{
outputStream = new BufferedOutputStream(clientSocket.getOutputStream());
}catch(Exception e){
e.printStackTrace();
outputStream=null;
setLinkStatus(false);
System.out.println(MODULE+ "Exception in initialize() while getting socket outputStream : " + e.getMessage());
}
if(outputStream != null){
try{
inputStream = new BufferedInputStream(clientSocket.getInputStream());
}catch(Exception e){
setLinkStatus(false);
System.out.println(MODULE+ "Exception in initialize() " + "while getting socket inputStream : " + e.getMessage());
}
setLinkStatus(true);
}
if(outputStream != null && inputStream != null){
isConnected = true;
}
}else{
System.out.println(MODULE+ "in initialize(), Connection is closed or null." );
setLinkStatus(false);
}
}
return isConnected;
}
public int writeData(byte[] msg){
int retValue = -1;
try{
if(isLinkActive() && (outputStream !=null)){
System.out.println(MODULE+ "Writting data ::::" + new String(msg)+ "::::");
outputStream.write(msg);// ed
outputStream.flush();
retValue = 1;
}else{
System.out.println(MODULE+ " in writeData() link is down so status:" + retValue );
}
}catch(Exception e){
e.printStackTrace();
retValue = -1;
System.out.println(MODULE+ "Exception in write() < message to be sent was = " + new String(msg) + " > : " + e.getMessage());
}
if(retValue == -1 && isLinkActive()){
setLinkStatus(false);
//sendNotification(TCPIPConstants.LINK_DOWN);
//releaseResources();
//resumeLinkSanityHelper();
}
System.out.println(MODULE+ " in writeData() Write status for ::"+ new String(msg) + ":: -->" +retValue);
return retValue;
}
public String readData() {
System.out.println(MODULE+"\tInside readDAta");
String response = null;
int bytesReceived=-1;
byte[] readBuffer = new byte[1024];
try{
long timetoread = System.currentTimeMillis();
if(inputStream == null || !(isLinkActive())){
System.out.println(MODULE+"Inputstream is null or link is down, returning null");
return null;
}
try{
System.out.println("Waiting to read data");
bytesReceived = inputStream.read(readBuffer);
System.out.println(MODULE+"# Byte Receieved #" + bytesReceived);
}catch(Exception e){
e.printStackTrace();
System.out.println(MODULE+"Error in readData() , Reason:"+e.getMessage());
if(isLinkActive()){
setLinkStatus(false);
//sendNotification(TCPIPConstants.LINK_DOWN);
releaseResources();
//resumeLinkSanityHelper();
}
}
if(bytesReceived > 0){
response = new String(readBuffer,0,bytesReceived); // ed
timetoread = System.currentTimeMillis() - timetoread;
System.out.println(MODULE + "Total Bytes Received: " + bytesReceived);
System.out.println(MODULE+ "Total Time Taken : " + timetoread);
System.out.println(MODULE+ "Length of data received : " + response.length());
System.out.println(MODULE+ "Data Received : ####" + response + "####");
}else{
////////// HERE MEANS TCP CONNECTION STATUS WILL CLOSE_WAIT
////////// SO RELEASING CONNECTION.
System.out.println(MODULE+ " Releasing Resource. bytesReceived is <= 0 : Total Bytes Received :"+ bytesReceived );
if(isLinkActive()){
setLinkStatus(false);
//sendNotification(TCPIPConstants.LINK_DOWN);
releaseResources();
//resumeLinkSanityHelper();
}
System.out.println(MODULE+ " Resource has been released.");
}
}catch(Exception e){
e.printStackTrace();
System.out.println(MODULE+ "In catch : Data Received : ####" + response + "####");
System.out.println(MODULE+ "Exception in readdata() : " + e);
}finally{
readBuffer=null;
}
return response;
}
public void releaseResources(){
System.out.println(MODULE+ "Releasing Resources....");
try{
if(clientSocket !=null)
clientSocket.close();
}catch(Exception e){
System.out.println(MODULE+ "In releaseResources() :Error closing socket."+e.getMessage());
}
try{
if(inputStream !=null )
inputStream.close();
}catch(Exception e){
System.out.println(MODULE+ "In releaseResources() :Error closing inputStream."+e.getMessage());
}
try{
if(outputStream != null){
outputStream.close();
}
}catch(Exception e){
System.out.println(MODULE+ "in releaseResources() :Error closing outputStream.");
}
System.out.println(MODULE + "Resources Relased...");
}
}
这里的establishConnection()方法将建立与服务器的连接。
注意:我一直在考虑使用ThreadPoolExecutor，但由于要求是同步的，所以我放弃了使用它的想法。