Package org.apache.commons.httpclient

Classes and interfaces supporting the client side of the HTTP protocol.

The HttpClient component supports the client-side of RFC 1945 (HTTP/1.0) and RFC 2616 (HTTP/1.1), several related specifications (RFC 2109 (Cookies), RFC 2617 (HTTP Authentication), etc.), and provides a framework by which new request types (methods) or HTTP extensions can can be easily created or supported.

The basis for the abstraction is provided by three types:

HttpConnection

represents a network connection to some HTTP host.

HttpMethod

represents a request to be made over some HttpConnection and contains the server's response.

HttpState

contains the HTTP attributes that may persist from request to request, such as cookies and authentication credentials.

and several simple bean-style classes:

Cookie

represents HTTP cookie.

Credentials

an interface representing a set of authentication credentials.

Header

represents an HTTP request or response header.

HeaderElement

represents a single element of a multi-part header.

UsernamePasswordCredentials

a username and password pair.

HttpClient provides a simple "user-agent" implementation that will suffice for many applications, but whose use is not required.

HttpClient also provides several utilities that may be useful when extending the framework:

HttpMethodBase

an abstract base implementation of HttpMethod, which may be extended to create new method types or to support additional protocol HTTP features.

HttpStatus

an enumeration of HttpStatus codes.

ChunkedOutputStream

an OutputStream wrapper supporting the "chunked" transfer encoding.

ChunkedInputStream

an InputStream wrapper supporting the "chunked" transfer encoding.

URIUtil

provides utilities for encoding and decoding URI's in the %HH format.

HttpClient Configuration with Java Properties

Java properties can be set at run time with the -Dname=value command line arguments to the application that uses HttpClient. These properties can also be set programaticly by calling System.getProperties().setProperty(name, value). This is the list of properties that HttpClient recognizes:

Name	Type	Effect
httpclient.useragent	String	Sets the User-Agent string to be sent on every HTTP request.
httpclient.authentication.preemptive	boolean	Sends authorization credentials without requiring explicit requests from the web server

Interface Summary

Interface	Description
Credentials	Authentication credentials.
HttpConnectionManager	An interface for classes that manage HttpConnections.
HttpMethod	HttpMethod interface represents a request to be sent via a HTTP connection and a corresponding response.
HttpMethodRetryHandler	A handler for determining if an HttpMethod should be retried after a recoverable exception during execution.
MethodRetryHandler	Deprecated. use HttpMethodRetryHandler

Class Summary

Class	Description
ChunkedInputStream	Transparently coalesces chunks of a HTTP stream that uses Transfer-Encoding chunked.
ChunkedOutputStream	Implements HTTP chunking support.
ConnectMethod	Establishes a tunneled HTTP connection via the CONNECT method.
ContentLengthInputStream	Cuts the wrapped InputStream off after a specified number of bytes.
Cookie	HTTP "magic-cookie" represents a piece of state information that the HTTP agent and the target server can exchange to maintain a session.
DefaultHttpMethodRetryHandler	The default HttpMethodRetryHandler used by HttpMethods.
DefaultMethodRetryHandler	Deprecated. use DefaultHttpMethodRetryHandler
Header	An HTTP header.
HeaderElement	One element of an HTTP header's value.
HeaderGroup	A class for combining a set of headers.
HostConfiguration	Holds all of the variables needed to describe an HTTP connection to a host.
HttpClient	An HTTP "user-agent", containing an HTTP state and one or more HTTP connections, to which HTTP methods can be applied.
HttpConnection	An abstraction of an HTTP InputStream and OutputStream pair, together with the relevant attributes.
HttpConstants	Deprecated. use EncodingUtil class
HttpHost	Holds all of the variables needed to describe an HTTP connection to a host.
HttpMethodBase	An abstract base implementation of HttpMethod.
HttpParser	A utility class for parsing http header values according to RFC-2616 Section 4 and 19.3.
HttpState	A container for HTTP attributes that may persist from request to request, such as cookies and authentication credentials.
HttpStatus	Constants enumerating the HTTP status codes.
HttpsURL	The HTTPS URL.
HttpURL	The HTTP URL.
HttpVersion	HTTP version, as specified in RFC 2616.
MultiThreadedHttpConnectionManager	Manages a set of HttpConnections for various HostConfigurations.
NameValuePair	A simple class encapsulating a name/value pair.
NTCredentials	Credentials for use with the NTLM authentication scheme which requires additional information.
ProxyClient	A client that provides sockets for communicating through HTTP proxies via the HTTP CONNECT method.
ProxyClient.ConnectResponse	Contains the method used to execute the connect along with the created socket.
ProxyHost	Holds all of the variables needed to describe an HTTP connection to a proxy.
SimpleHttpConnectionManager	A connection manager that provides access to a single HttpConnection.
StatusLine	Represents a Status-Line as returned from a HTTP server.
URI	The interface for the URI(Uniform Resource Identifiers) version of RFC 2396.
URI.LocaleToCharsetMap	A mapping to determine the (somewhat arbitrarily) preferred charset for a given locale.
UsernamePasswordCredentials	Username and password Credentials.

Exception Summary

Exception	Description
CircularRedirectException	Signals a circular redirect
ConnectionPoolTimeoutException	A timeout while connecting waiting for an available connection from an HttpConnectionManager.
ConnectTimeoutException	A timeout while connecting to an HTTP server or waiting for an available connection from an HttpConnectionManager.
HttpContentTooLargeException	Signals that the response content was larger than anticipated.
HttpException	Signals that an HTTP or HttpClient exception has occurred.
HttpRecoverableException	Deprecated. no longer used
InvalidRedirectLocationException	Signals violation of HTTP specification caused by an invalid redirect location
NoHttpResponseException	Signals that the target server failed to respond with a valid HTTP response.
ProtocolException	Signals that an HTTP protocol violation has occurred.
RedirectException	Signals violation of HTTP specification caused by an invalid redirect
URI.DefaultCharsetChanged	The charset-changed normal operation to represent to be required to alert to user the fact the default charset is changed.
URIException	The URI parsing and escape encoding exception.

Error Summary

Error	Description
HttpClientError	Signals that an error has occurred.