Module jdk.httpserver

Package com.sun.net.httpserver

Class HttpServer

java.lang.Object

com.sun.net.httpserver.HttpServer

Direct Known Subclasses:

HttpsServer

public abstract class HttpServer
extends Object

This class implements a simple HTTP server. A HttpServer is bound to an IP address and port number and listens for incoming TCP connections from clients on this address. The sub-class HttpsServer implements a server which handles HTTPS requests.

One or more HttpHandler objects must be associated with a server in order to process requests. Each such HttpHandler is registered with a root URI path which represents the location of the application or service on this server. The mapping of a handler to a HttpServer is encapsulated by a HttpContext object. HttpContexts are created by calling createContext(String,HttpHandler). Any request for which no handler can be found is rejected with a 404 response. Management of threads can be done external to this object by providing a Executor object. If none is provided a default implementation is used.

Mapping request URIs to HttpContext paths

When a HTTP request is received, the appropriate HttpContext (and handler) is located by finding the context whose path is the longest matching prefix of the request URI's path. Paths are matched literally, which means that the strings are compared case sensitively, and with no conversion to or from any encoded forms. For example, given a HttpServer with the following HttpContexts configured:

description

Context	Context path
ctx1	"/"
ctx2	"/apps/"
ctx3	"/apps/foo/"

The following table shows some request URIs and which, if any context they would match with:

description

Request URI	Matches context
"http://foo.com/apps/foo/bar"	ctx3
"http://foo.com/apps/Foo/bar"	no match, wrong case
"http://foo.com/apps/app1"	ctx2
"http://foo.com/foo"	ctx1

Note about socket backlogs

When binding to an address and port number, the application can also specify an integer backlog parameter. This represents the maximum number of incoming TCP connections which the system will queue internally. Connections are queued while they are waiting to be accepted by the HttpServer. When the limit is reached, further connections may be rejected (or possibly ignored) by the underlying TCP implementation. Setting the right backlog value is a compromise between efficient resource usage in the TCP layer (not setting it too high) and allowing adequate throughput of incoming requests (not setting it too low).

Since:

1.6

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	HttpServer()	Constructor for subclasses to call.

Method Summary

Modifier and Type	Method	Description
abstract void	bind(InetSocketAddress addr, int backlog)	Binds a currently unbound HttpServer to the given address and port number.
static HttpServer	create()	Creates a HttpServer instance which is initially not bound to any local address/port.
static HttpServer	create(InetSocketAddress addr, int backlog)	Create a HttpServer instance which will bind to the specified InetSocketAddress (IP address and port number).
static HttpServer	create(InetSocketAddress addr, int backlog, String path, HttpHandler handler, Filter... filters)	Creates an HttpServer instance with an initial context.
abstract HttpContext	createContext(String path)	Creates a HttpContext without initially specifying a handler.
abstract HttpContext	createContext(String path, HttpHandler handler)	Creates a HttpContext.
abstract InetSocketAddress	getAddress()	Returns the address this server is listening on
abstract Executor	getExecutor()	Returns this server's Executor object if one was specified with setExecutor(Executor), or null if none was specified.
abstract void	removeContext(HttpContext context)	Removes the given context from the server.
abstract void	removeContext(String path)	Removes the context identified by the given path from the server.
abstract void	setExecutor(Executor executor)	Sets this server's Executor object.
abstract void	start()	Starts this server in a new background thread.
abstract void	stop(int delay)	Stops this server by closing the listening socket and disallowing any new exchanges from being processed.

Methods declared in class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

HttpServer

protected HttpServer()

Constructor for subclasses to call.

Method Details

create

public static HttpServer create()
                         throws IOException

Creates a HttpServer instance which is initially not bound to any local address/port. The HttpServer is acquired from the currently installed HttpServerProvider. The server must be bound using bind(InetSocketAddress,int) before it can be used.

Returns:

an instance of HttpServer

Throws:

IOException - if an I/O error occurs

create

public static HttpServer create(InetSocketAddress addr,
 int backlog)
                         throws IOException

Create a HttpServer instance which will bind to the specified InetSocketAddress (IP address and port number). A maximum backlog can also be specified. This is the maximum number of queued incoming connections to allow on the listening socket. Queued TCP connections exceeding this limit may be rejected by the TCP implementation. The HttpServer is acquired from the currently installed HttpServerProvider

Parameters:

addr - the address to listen on, if null then bind(InetSocketAddress, int) must be called to set the address

backlog - the socket backlog. If this value is less than or equal to zero, then a system default value is used

Returns:

an instance of HttpServer

Throws:

IOException - if an I/O error occurs

BindException - if the server cannot bind to the requested address, or if the server is already bound

create

public static HttpServer create(InetSocketAddress addr,
 int backlog,
 String path,
 HttpHandler handler,
 Filter... filters)
                         throws IOException

Creates an HttpServer instance with an initial context.

The server is created with an initial context that maps the URI path to the exchange handler. The initial context is created as if by an invocation of createContext(path). The filters, if any, are added to the initial context, in the order they are given. The returned server is not started so can be configured further if required.

The server instance will bind to the given InetSocketAddress.

A maximum backlog can also be specified. This is the maximum number of queued incoming connections to allow on the listening socket. Queued TCP connections exceeding this limit may be rejected by the TCP implementation. The HttpServer is acquired from the currently installed HttpServerProvider.

Parameters:

addr - the address to listen on, if null then bind must be called to set the address

backlog - the socket backlog. If this value is less than or equal to zero, then a system default value is used

path - the root URI path of the context, must be absolute

handler - the HttpHandler for the context

filters - the Filters for the context, optional

Returns:

the HttpServer

Throws:

BindException - if the server cannot bind to the address

IOException - if an I/O error occurs

IllegalArgumentException - if path is invalid

NullPointerException - if any of: path, handler, filters, or any element of filters, are null

Since:

18

bind

public abstract void bind(InetSocketAddress addr,
 int backlog)
                   throws IOException

Binds a currently unbound HttpServer to the given address and port number. A maximum backlog can also be specified. This is the maximum number of queued incoming connections to allow on the listening socket. Queued TCP connections exceeding this limit may be rejected by the TCP implementation.

Parameters:

addr - the address to listen on

backlog - the socket backlog. If this value is less than or equal to zero, then a system default value is used

Throws:

BindException - if the server cannot bind to the requested address or if the server is already bound

NullPointerException - if addr is null

IOException

start

public abstract void start()

Starts this server in a new background thread. The background thread inherits the priority, thread group and context class loader of the caller.

setExecutor

public abstract void setExecutor(Executor executor)

Sets this server's Executor object. An Executor must be established before start() is called. All HTTP requests are handled in tasks given to the executor. If this method is not called (before start()) or if it is called with a null Executor, then a default implementation is used, which uses the thread which was created by the start() method.

Parameters:

executor - the Executor to set, or null for default implementation

Throws:

IllegalStateException - if the server is already started

getExecutor

public abstract Executor getExecutor()

Returns this server's Executor object if one was specified with setExecutor(Executor), or null if none was specified.

Returns:

the Executor established for this server or null if not set.

stop

public abstract void stop(int delay)

Stops this server by closing the listening socket and disallowing any new exchanges from being processed. The method will then block until all current exchange handlers have completed or else when approximately delay seconds have elapsed (whichever happens sooner). Then, all open TCP connections are closed, the background thread created by start() exits, and the method returns. Once stopped, a HttpServer cannot be re-used.

Parameters:

delay - the maximum time in seconds to wait until exchanges have finished

Throws:

IllegalArgumentException - if delay is less than zero

createContext

public abstract HttpContext createContext(String path,
 HttpHandler handler)

Creates a HttpContext. A HttpContext represents a mapping from a URI path to a exchange handler on this HttpServer. Once created, all requests received by the server for the path will be handled by calling the given handler object. The context is identified by the path, and can later be removed from the server using this with the removeContext(String) method.

The path specifies the root URI path for this context. The first character of path must be '/'.

The class overview describes how incoming request URIs are mapped to HttpContext instances.

API Note:

The path should generally, but is not required to, end with '/'. If the path does not end with '/', eg such as with "/foo" then this would match requests with a path of "/foobar" or "/foo/bar".

Parameters:

path - the root URI path to associate the context with

handler - the handler to invoke for incoming requests

Returns:

an instance of HttpContext

Throws:

IllegalArgumentException - if path is invalid, or if a context already exists for this path

NullPointerException - if either path, or handler are null

createContext

public abstract HttpContext createContext(String path)

Creates a HttpContext without initially specifying a handler. The handler must later be specified using HttpContext.setHandler(HttpHandler). A HttpContext represents a mapping from a URI path to an exchange handler on this HttpServer. Once created, and when the handler has been set, all requests received by the server for the path will be handled by calling the handler object. The context is identified by the path, and can later be removed from the server using this with the removeContext(String) method.

The path specifies the root URI path for this context. The first character of path must be '/'.

The class overview describes how incoming request URIs are mapped to HttpContext instances.

API Note:

The path should generally, but is not required to, end with '/'. If the path does not end with '/', eg such as with "/foo" then this would match requests with a path of "/foobar" or "/foo/bar".

Parameters:

path - the root URI path to associate the context with

Returns:

an instance of HttpContext

Throws:

IllegalArgumentException - if path is invalid, or if a context already exists for this path

NullPointerException - if path is null

removeContext

public abstract void removeContext(String path)
                            throws IllegalArgumentException

Removes the context identified by the given path from the server. Removing a context does not affect exchanges currently being processed but prevents new ones from being accepted.

Parameters:

path - the path of the handler to remove

Throws:

IllegalArgumentException - if no handler corresponding to this path exists.

NullPointerException - if path is null

removeContext

public abstract void removeContext(HttpContext context)

Removes the given context from the server. Removing a context does not affect exchanges currently being processed but prevents new ones from being accepted.

Parameters:

context - the context to remove

Throws:

NullPointerException - if context is null

getAddress

public abstract InetSocketAddress getAddress()

Returns the address this server is listening on

Returns:

the InetSocketAddress the server is listening on