- java.lang.Object
-
- java.net.ServerSocket
-
- All Implemented Interfaces:
- Closeable, AutoCloseable
- Direct Known Subclasses:
- SSLServerSocket
public class ServerSocket extends Object implements Closeable
This class implements server sockets. A server socket waits for requests to come in over the network. It performs some operation based on that request, and then possibly returns a result to the requester.The actual work of the server socket is performed by an instance of the
SocketImpl
class. An application can change the socket factory that creates the socket implementation to configure itself to create sockets appropriate to the local firewall.- Since:
- JDK1.0
- See Also:
SocketImpl
,setSocketFactory(java.net.SocketImplFactory)
,ServerSocketChannel
-
-
Constructor Summary
Constructors Constructor and Description ServerSocket()
Creates an unbound server socket.ServerSocket(int port)
Creates a server socket, bound to the specified port.ServerSocket(int port, int backlog)
Creates a server socket and binds it to the specified local port number, with the specified backlog.ServerSocket(int port, int backlog, InetAddress bindAddr)
Create a server with the specified port, listen backlog, and local IP address to bind to.
-
Method Summary
Methods Modifier and Type Method and Description Socket
accept()
Listens for a connection to be made to this socket and accepts it.void
bind(SocketAddress endpoint)
Binds theServerSocket
to a specific address (IP address and port number).void
bind(SocketAddress endpoint, int backlog)
Binds theServerSocket
to a specific address (IP address and port number).void
close()
Closes this socket.ServerSocketChannel
getChannel()
Returns the uniqueServerSocketChannel
object associated with this socket, if any.InetAddress
getInetAddress()
Returns the local address of this server socket.int
getLocalPort()
Returns the port number on which this socket is listening.SocketAddress
getLocalSocketAddress()
Returns the address of the endpoint this socket is bound to, ornull
if it is not bound yet.int
getReceiveBufferSize()
Gets the value of the SO_RCVBUF option for this ServerSocket, that is the proposed buffer size that will be used for Sockets accepted from this ServerSocket.boolean
getReuseAddress()
Tests if SO_REUSEADDR is enabled.int
getSoTimeout()
Retrieve setting for SO_TIMEOUT.protected void
implAccept(Socket s)
Subclasses of ServerSocket use this method to override accept() to return their own subclass of socket.boolean
isBound()
Returns the binding state of the ServerSocket.boolean
isClosed()
Returns the closed state of the ServerSocket.void
setPerformancePreferences(int connectionTime, int latency, int bandwidth)
Sets performance preferences for this ServerSocket.void
setReceiveBufferSize(int size)
Sets a default proposed value for the SO_RCVBUF option for sockets accepted from this ServerSocket.void
setReuseAddress(boolean on)
Enable/disable the SO_REUSEADDR socket option.static void
setSocketFactory(SocketImplFactory fac)
Sets the server socket implementation factory for the application.void
setSoTimeout(int timeout)
Enable/disable SO_TIMEOUT with the specified timeout, in milliseconds.String
toString()
Returns the implementation address and implementation port of this socket as aString
.
-
-
-
Constructor Detail
-
ServerSocket
public ServerSocket() throws IOException
Creates an unbound server socket.- Throws:
IOException
- IO error when opening the socket.
-
ServerSocket
public ServerSocket(int port) throws IOException
Creates a server socket, bound to the specified port. A port number of0
means that the port number is automatically allocated, typically from an ephemeral port range. This port number can then be retrieved by callinggetLocalPort
.The maximum queue length for incoming connection indications (a request to connect) is set to
50
. If a connection indication arrives when the queue is full, the connection is refused.If the application has specified a server socket factory, that factory's
createSocketImpl
method is called to create the actual socket implementation. Otherwise a "plain" socket is created.If there is a security manager, its
checkListen
method is called with theport
argument as its argument to ensure the operation is allowed. This could result in a SecurityException.- Parameters:
port
- the port number, or0
to use a port number that is automatically allocated.- Throws:
IOException
- if an I/O error occurs when opening the socket.SecurityException
- if a security manager exists and itscheckListen
method doesn't allow the operation.IllegalArgumentException
- if the port parameter is outside the specified range of valid port values, which is between 0 and 65535, inclusive.- See Also:
SocketImpl
,SocketImplFactory.createSocketImpl()
,setSocketFactory(java.net.SocketImplFactory)
,SecurityManager.checkListen(int)
-
ServerSocket
public ServerSocket(int port, int backlog) throws IOException
Creates a server socket and binds it to the specified local port number, with the specified backlog. A port number of0
means that the port number is automatically allocated, typically from an ephemeral port range. This port number can then be retrieved by callinggetLocalPort
.The maximum queue length for incoming connection indications (a request to connect) is set to the
backlog
parameter. If a connection indication arrives when the queue is full, the connection is refused.If the application has specified a server socket factory, that factory's
createSocketImpl
method is called to create the actual socket implementation. Otherwise a "plain" socket is created.If there is a security manager, its
checkListen
method is called with theport
argument as its argument to ensure the operation is allowed. This could result in a SecurityException. Thebacklog
argument is the requested maximum number of pending connections on the socket. Its exact semantics are implementation specific. In particular, an implementation may impose a maximum length or may choose to ignore the parameter altogther. The value provided should be greater than0
. If it is less than or equal to0
, then an implementation specific default will be used.- Parameters:
port
- the port number, or0
to use a port number that is automatically allocated.backlog
- requested maximum length of the queue of incoming connections.- Throws:
IOException
- if an I/O error occurs when opening the socket.SecurityException
- if a security manager exists and itscheckListen
method doesn't allow the operation.IllegalArgumentException
- if the port parameter is outside the specified range of valid port values, which is between 0 and 65535, inclusive.- See Also:
SocketImpl
,SocketImplFactory.createSocketImpl()
,setSocketFactory(java.net.SocketImplFactory)
,SecurityManager.checkListen(int)
-
ServerSocket
public ServerSocket(int port, int backlog, InetAddress bindAddr) throws IOException
Create a server with the specified port, listen backlog, and local IP address to bind to. The bindAddr argument can be used on a multi-homed host for a ServerSocket that will only accept connect requests to one of its addresses. If bindAddr is null, it will default accepting connections on any/all local addresses. The port must be between 0 and 65535, inclusive. A port number of0
means that the port number is automatically allocated, typically from an ephemeral port range. This port number can then be retrieved by callinggetLocalPort
.If there is a security manager, this method calls its
checkListen
method with theport
argument as its argument to ensure the operation is allowed. This could result in a SecurityException. Thebacklog
argument is the requested maximum number of pending connections on the socket. Its exact semantics are implementation specific. In particular, an implementation may impose a maximum length or may choose to ignore the parameter altogther. The value provided should be greater than0
. If it is less than or equal to0
, then an implementation specific default will be used.- Parameters:
port
- the port number, or0
to use a port number that is automatically allocated.backlog
- requested maximum length of the queue of incoming connections.bindAddr
- the local InetAddress the server will bind to- Throws:
SecurityException
- if a security manager exists and itscheckListen
method doesn't allow the operation.IOException
- if an I/O error occurs when opening the socket.IllegalArgumentException
- if the port parameter is outside the specified range of valid port values, which is between 0 and 65535, inclusive.- Since:
- JDK1.1
- See Also:
SocketOptions
,SocketImpl
,SecurityManager.checkListen(int)
-
-
Method Detail
-
bind
public void bind(SocketAddress endpoint) throws IOException
Binds theServerSocket
to a specific address (IP address and port number).If the address is
null
, then the system will pick up an ephemeral port and a valid local address to bind the socket.- Parameters:
endpoint
- The IP address & port number to bind to.- Throws:
IOException
- if the bind operation fails, or if the socket is already bound.SecurityException
- if aSecurityManager
is present and itscheckListen
method doesn't allow the operation.IllegalArgumentException
- if endpoint is a SocketAddress subclass not supported by this socket- Since:
- 1.4
-
bind
public void bind(SocketAddress endpoint, int backlog) throws IOException
Binds theServerSocket
to a specific address (IP address and port number).If the address is
null
, then the system will pick up an ephemeral port and a valid local address to bind the socket.The
backlog
argument is the requested maximum number of pending connections on the socket. Its exact semantics are implementation specific. In particular, an implementation may impose a maximum length or may choose to ignore the parameter altogther. The value provided should be greater than0
. If it is less than or equal to0
, then an implementation specific default will be used.- Parameters:
endpoint
- The IP address & port number to bind to.backlog
- requested maximum length of the queue of incoming connections.- Throws:
IOException
- if the bind operation fails, or if the socket is already bound.SecurityException
- if aSecurityManager
is present and itscheckListen
method doesn't allow the operation.IllegalArgumentException
- if endpoint is a SocketAddress subclass not supported by this socket- Since:
- 1.4
-
getInetAddress
public InetAddress getInetAddress()
Returns the local address of this server socket.If the socket was bound prior to being
closed
, then this method will continue to return the local address after the socket is closed.- Returns:
- the address to which this socket is bound,
or
null
if the socket is unbound.
-
getLocalPort
public int getLocalPort()
Returns the port number on which this socket is listening.If the socket was bound prior to being
closed
, then this method will continue to return the port number after the socket is closed.- Returns:
- the port number to which this socket is listening or -1 if the socket is not bound yet.
-
getLocalSocketAddress
public SocketAddress getLocalSocketAddress()
Returns the address of the endpoint this socket is bound to, ornull
if it is not bound yet.If the socket was bound prior to being
closed
, then this method will continue to return the address of the endpoint after the socket is closed.- Returns:
- a
SocketAddress
representing the local endpoint of this socket, ornull
if it is not bound yet. - Since:
- 1.4
- See Also:
getInetAddress()
,getLocalPort()
,bind(SocketAddress)
-
accept
public Socket accept() throws IOException
Listens for a connection to be made to this socket and accepts it. The method blocks until a connection is made.A new Socket
s
is created and, if there is a security manager, the security manager'scheckAccept
method is called withs.getInetAddress().getHostAddress()
ands.getPort()
as its arguments to ensure the operation is allowed. This could result in a SecurityException.- Returns:
- the new Socket
- Throws:
IOException
- if an I/O error occurs when waiting for a connection.SecurityException
- if a security manager exists and itscheckAccept
method doesn't allow the operation.SocketTimeoutException
- if a timeout was previously set with setSoTimeout and the timeout has been reached.IllegalBlockingModeException
- if this socket has an associated channel, the channel is in non-blocking mode, and there is no connection ready to be accepted- See Also:
SecurityManager.checkAccept(java.lang.String, int)
-
implAccept
protected final void implAccept(Socket s) throws IOException
Subclasses of ServerSocket use this method to override accept() to return their own subclass of socket. So a FooServerSocket will typically hand this method an empty FooSocket. On return from implAccept the FooSocket will be connected to a client.- Parameters:
s
- the Socket- Throws:
IllegalBlockingModeException
- if this socket has an associated channel, and the channel is in non-blocking modeIOException
- if an I/O error occurs when waiting for a connection.- Since:
- JDK1.1
-
close
public void close() throws IOException
Closes this socket. Any thread currently blocked inaccept()
will throw aSocketException
.If this socket has an associated channel then the channel is closed as well.
- Specified by:
close
in interfaceCloseable
- Specified by:
close
in interfaceAutoCloseable
- Throws:
IOException
- if an I/O error occurs when closing the socket.
-
getChannel
public ServerSocketChannel getChannel()
Returns the uniqueServerSocketChannel
object associated with this socket, if any.A server socket will have a channel if, and only if, the channel itself was created via the
ServerSocketChannel.open
method.- Returns:
- the server-socket channel associated with this socket, or null if this socket was not created for a channel
- Since:
- 1.4
-
isBound
public boolean isBound()
Returns the binding state of the ServerSocket.- Returns:
- true if the ServerSocket succesfuly bound to an address
- Since:
- 1.4
-
isClosed
public boolean isClosed()
Returns the closed state of the ServerSocket.- Returns:
- true if the socket has been closed
- Since:
- 1.4
-
setSoTimeout
public void setSoTimeout(int timeout) throws SocketException
Enable/disable SO_TIMEOUT with the specified timeout, in milliseconds. With this option set to a non-zero timeout, a call to accept() for this ServerSocket will block for only this amount of time. If the timeout expires, a java.net.SocketTimeoutException is raised, though the ServerSocket is still valid. The option must be enabled prior to entering the blocking operation to have effect. The timeout must be > 0. A timeout of zero is interpreted as an infinite timeout.- Parameters:
timeout
- the specified timeout, in milliseconds- Throws:
SocketException
- if there is an error in the underlying protocol, such as a TCP error.- Since:
- JDK1.1
- See Also:
getSoTimeout()
-
getSoTimeout
public int getSoTimeout() throws IOException
Retrieve setting for SO_TIMEOUT. 0 returns implies that the option is disabled (i.e., timeout of infinity).- Returns:
- the SO_TIMEOUT value
- Throws:
IOException
- if an I/O error occurs- Since:
- JDK1.1
- See Also:
setSoTimeout(int)
-
setReuseAddress
public void setReuseAddress(boolean on) throws SocketException
Enable/disable the SO_REUSEADDR socket option.When a TCP connection is closed the connection may remain in a timeout state for a period of time after the connection is closed (typically known as the TIME_WAIT state or 2MSL wait state). For applications using a well known socket address or port it may not be possible to bind a socket to the required SocketAddress if there is a connection in the timeout state involving the socket address or port.
Enabling SO_REUSEADDR prior to binding the socket using
bind(SocketAddress)
allows the socket to be bound even though a previous connection is in a timeout state.When a ServerSocket is created the initial setting of SO_REUSEADDR is not defined. Applications can use
getReuseAddress()
to determine the initial setting of SO_REUSEADDR.The behaviour when SO_REUSEADDR is enabled or disabled after a socket is bound (See
isBound()
) is not defined.- Parameters:
on
- whether to enable or disable the socket option- Throws:
SocketException
- if an error occurs enabling or disabling the SO_RESUEADDR socket option, or the socket is closed.- Since:
- 1.4
- See Also:
getReuseAddress()
,bind(SocketAddress)
,isBound()
,isClosed()
-
getReuseAddress
public boolean getReuseAddress() throws SocketException
Tests if SO_REUSEADDR is enabled.- Returns:
- a
boolean
indicating whether or not SO_REUSEADDR is enabled. - Throws:
SocketException
- if there is an error in the underlying protocol, such as a TCP error.- Since:
- 1.4
- See Also:
setReuseAddress(boolean)
-
toString
public String toString()
Returns the implementation address and implementation port of this socket as aString
.
-
setSocketFactory
public static void setSocketFactory(SocketImplFactory fac) throws IOException
Sets the server socket implementation factory for the application. The factory can be specified only once.When an application creates a new server socket, the socket implementation factory's
createSocketImpl
method is called to create the actual socket implementation.Passing
null
to the method is a no-op unless the factory was already set.If there is a security manager, this method first calls the security manager's
checkSetFactory
method to ensure the operation is allowed. This could result in a SecurityException.- Parameters:
fac
- the desired factory.- Throws:
IOException
- if an I/O error occurs when setting the socket factory.SocketException
- if the factory has already been defined.SecurityException
- if a security manager exists and itscheckSetFactory
method doesn't allow the operation.- See Also:
SocketImplFactory.createSocketImpl()
,SecurityManager.checkSetFactory()
-
setReceiveBufferSize
public void setReceiveBufferSize(int size) throws SocketException
Sets a default proposed value for the SO_RCVBUF option for sockets accepted from this ServerSocket. The value actually set in the accepted socket must be determined by callingSocket.getReceiveBufferSize()
after the socket is returned byaccept()
.The value of SO_RCVBUF is used both to set the size of the internal socket receive buffer, and to set the size of the TCP receive window that is advertized to the remote peer.
It is possible to change the value subsequently, by calling
Socket.setReceiveBufferSize(int)
. However, if the application wishes to allow a receive window larger than 64K bytes, as defined by RFC1323 then the proposed value must be set in the ServerSocket before it is bound to a local address. This implies, that the ServerSocket must be created with the no-argument constructor, then setReceiveBufferSize() must be called and lastly the ServerSocket is bound to an address by calling bind().Failure to do this will not cause an error, and the buffer size may be set to the requested value but the TCP receive window in sockets accepted from this ServerSocket will be no larger than 64K bytes.
- Parameters:
size
- the size to which to set the receive buffer size. This value must be greater than 0.- Throws:
SocketException
- if there is an error in the underlying protocol, such as a TCP error.IllegalArgumentException
- if the value is 0 or is negative.- Since:
- 1.4
- See Also:
getReceiveBufferSize()
-
getReceiveBufferSize
public int getReceiveBufferSize() throws SocketException
Gets the value of the SO_RCVBUF option for this ServerSocket, that is the proposed buffer size that will be used for Sockets accepted from this ServerSocket.Note, the value actually set in the accepted socket is determined by calling
Socket.getReceiveBufferSize()
.- Returns:
- the value of the SO_RCVBUF option for this Socket.
- Throws:
SocketException
- if there is an error in the underlying protocol, such as a TCP error.- Since:
- 1.4
- See Also:
setReceiveBufferSize(int)
-
setPerformancePreferences
public void setPerformancePreferences(int connectionTime, int latency, int bandwidth)
Sets performance preferences for this ServerSocket.Sockets use the TCP/IP protocol by default. Some implementations may offer alternative protocols which have different performance characteristics than TCP/IP. This method allows the application to express its own preferences as to how these tradeoffs should be made when the implementation chooses from the available protocols.
Performance preferences are described by three integers whose values indicate the relative importance of short connection time, low latency, and high bandwidth. The absolute values of the integers are irrelevant; in order to choose a protocol the values are simply compared, with larger values indicating stronger preferences. If the application prefers short connection time over both low latency and high bandwidth, for example, then it could invoke this method with the values (1, 0, 0). If the application prefers high bandwidth above low latency, and low latency above short connection time, then it could invoke this method with the values (0, 1, 2).
Invoking this method after this socket has been bound will have no effect. This implies that in order to use this capability requires the socket to be created with the no-argument constructor.
- Parameters:
connectionTime
- An int expressing the relative importance of a short connection timelatency
- An int expressing the relative importance of low latencybandwidth
- An int expressing the relative importance of high bandwidth- Since:
- 1.5
-
-
Deutsche Übersetzung
Sie haben gebeten, diese Seite auf Deutsch zu besuchen. Momentan ist nur die Oberfläche übersetzt, aber noch nicht der gesamte Inhalt.Wenn Sie mir bei Übersetzungen helfen wollen, ist Ihr Beitrag willkommen. Alles, was Sie tun müssen, ist, sich auf der Website zu registrieren und mir eine Nachricht zu schicken, in der Sie gebeten werden, Sie der Gruppe der Übersetzer hinzuzufügen, die Ihnen die Möglichkeit gibt, die gewünschten Seiten zu übersetzen. Ein Link am Ende jeder übersetzten Seite zeigt an, dass Sie der Übersetzer sind und einen Link zu Ihrem Profil haben.
Vielen Dank im Voraus.
Dokument erstellt 11/06/2005, zuletzt geändert 04/03/2020
Quelle des gedruckten Dokuments:https://www.gaudry.be/de/java-api-rf-java/net/serversocket.html
Die Infobro ist eine persönliche Seite, deren Inhalt in meiner alleinigen Verantwortung liegt. Der Text ist unter der CreativeCommons-Lizenz (BY-NC-SA) verfügbar. Weitere Informationen auf die Nutzungsbedingungen und dem Autor.
Referenzen
Diese Verweise und Links verweisen auf Dokumente, die während des Schreibens dieser Seite konsultiert wurden, oder die zusätzliche Informationen liefern können, aber die Autoren dieser Quellen können nicht für den Inhalt dieser Seite verantwortlich gemacht werden.
Der Autor Diese Website ist allein dafür verantwortlich, wie die verschiedenen Konzepte und Freiheiten, die mit den Nachschlagewerken gemacht werden, hier dargestellt werden. Denken Sie daran, dass Sie mehrere Quellinformationen austauschen müssen, um das Risiko von Fehlern zu reduzieren.