```
public interface HttpRequestHeader
```
A list of common request header constants of the HTTP protocol. See http://en.wikipedia.org/wiki/List_of_HTTP_header_fields.

Field Summary

Fields
Modifier and Type	Field	Description
`static java.lang.String`	`Accept`	Content-Types that are acceptable for the response.
`static java.lang.String`	`AcceptCharset`	Character sets that are acceptable.
`static java.lang.String`	`AcceptDatetime`	Acceptable version in time.
`static java.lang.String`	`AcceptEncoding`	List of acceptable encodings.
`static java.lang.String`	`AcceptLanguage`	List of acceptable human languages for response.
`static java.lang.String`	`Authorization`	Authentication credentials for HTTP authentication.
`static java.lang.String`	`CacheControl`	Used to specify directives that must be obeyed by all caching mechanisms along the request-response chain.
`static java.lang.String`	`Connection`	What type of connection the user-agent would prefer.
`static java.lang.String`	`ContentLength`	The length of the request body in octets (8-bit bytes).
`static java.lang.String`	`ContentMD5`	A Base64-encoded binary MD5 sum of the content of the request body.
`static java.lang.String`	`ContentType`	The MIME type of the body of the request (used with POST and PUT requests).
`static java.lang.String`	`Cookie`	An HTTP cookie previously sent by the server with Set-Cookie (below).
`static java.lang.String`	`Date`	The date and time that the message was sent (in "HTTP-date" format as defined by RFC 7231).
`static java.lang.String`	`Expect`	Indicates that particular server behaviors are required by the client.
`static java.lang.String`	`From`	The email address of the user making the request.
`static java.lang.String`	`Host`	The domain name of the server (for virtual hosting), and the TCP port number on which the server is listening.
`static java.lang.String`	`IfMatch`	Only perform the action if the client supplied entity matches the same entity on the server.
`static java.lang.String`	`IfModifiedSince`	Allows a 304 Not Modified to be returned if content is unchanged.
`static java.lang.String`	`IfNoneMatch`	Allows a 304 Not Modified to be returned if content is unchanged, see HTTP ETag.
`static java.lang.String`	`IfRange`	If the entity is unchanged, send me the part(s) that I am missing=""; otherwise, send me the entire new entity.
`static java.lang.String`	`IfUnmodifiedSince`	Only send the response if the entity has not been modified since a specific time.
`static java.lang.String`	`MaxForwards`	Limit the number of times the message can be forwarded through proxies or gateways.
`static java.lang.String`	`Origin`	Initiates a request for cross-origin resource sharing (asks server for an 'Access-Control-Allow-Origin' response field).
`static java.lang.String`	`Pragma`	Implementation-specific fields that may have various effects anywhere along the request-response chain.
`static java.lang.String`	`ProxyAuthorization`	Authorization credentials for connecting to a proxy.
`static java.lang.String`	`Range`	Request only part of an entity.
`static java.lang.String`	`Referer`	This is the address of the previous web page from which a link to the currently requested page was followed.
`static java.lang.String`	`TE`	The transfer encodings the user agent is willing to accept: the same values as for the response header field Transfer-Encoding can be used, plus the "trailers" value (related to the "chunked" transfer method) to notify the server it expects to receive additional fields in the trailer after the last, zero-sized, chunk.
`static java.lang.String`	`Upgrade`	Ask the server to upgrade to another protocol.
`static java.lang.String`	`UserAgent`	The user agent string of the user agent.
`static java.lang.String`	`Via`	Informs the server of proxies through which the request was sent.
`static java.lang.String`	`Warning`	A general warning about possible problems with the entity body.

- Field Detail
  - Accept
```
static final java.lang.String Accept
```
    Content-Types that are acceptable for the response.
    Example: Accept: text/plain
    
    See Also:
    
    Constant Field Values
  - AcceptCharset
```
static final java.lang.String AcceptCharset
```
    Character sets that are acceptable.
    Example: Accept-Charset: utf-8
    
    See Also:
    
    Constant Field Values
  - AcceptEncoding
```
static final java.lang.String AcceptEncoding
```
    List of acceptable encodings.
    Example: Accept-Encoding: gzip, deflate
    
    See Also:
    
    Constant Field Values
  - AcceptLanguage
```
static final java.lang.String AcceptLanguage
```
    List of acceptable human languages for response.
    Example: Accept-Language: en-US
    
    See Also:
    
    Constant Field Values
  - AcceptDatetime
```
static final java.lang.String AcceptDatetime
```
    Acceptable version in time.
    Example: Accept-Datetime: Thu, 31 May 2007 20:35:00 GMT
    
    See Also:
    
    Constant Field Values
  - Authorization
```
static final java.lang.String Authorization
```
    Authentication credentials for HTTP authentication.
    Example: Authorization: Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ==
    
    See Also:
    
    Constant Field Values
  - CacheControl
```
static final java.lang.String CacheControl
```
    Used to specify directives that must be obeyed by all caching mechanisms along the request-response chain.
    Example: Cache-Control: no-cache
    
    See Also:
    
    Constant Field Values
  - Connection
```
static final java.lang.String Connection
```
    What type of connection the user-agent would prefer.
    Example: Connection: keep-alive
    
    See Also:
    
    Constant Field Values
  - Cookie
```
static final java.lang.String Cookie
```
    An HTTP cookie previously sent by the server with Set-Cookie (below).
    Example: Cookie: $Version=1=""; Skin=new="";
    
    See Also:
    
    Constant Field Values
  - ContentLength
```
static final java.lang.String ContentLength
```
    The length of the request body in octets (8-bit bytes).
    Example: Content-Length: 348
    
    See Also:
    
    Constant Field Values
  - ContentMD5
```
static final java.lang.String ContentMD5
```
    A Base64-encoded binary MD5 sum of the content of the request body.
    Example: Content-MD5: Q2hlY2sgSW50ZWdyaXR5IQ==
    
    See Also:
    
    Constant Field Values
  - ContentType
```
static final java.lang.String ContentType
```
    The MIME type of the body of the request (used with POST and PUT requests).
    Example: Content-Type: application/x-www-form-urlencoded
    
    See Also:
    
    Constant Field Values
  - Date
```
static final java.lang.String Date
```
    The date and time that the message was sent (in "HTTP-date" format as defined by RFC 7231).
    Example: Date: Tue, 15 Nov 1994 08:12:31 GMT
    
    See Also:
    
    Constant Field Values
  - Expect
```
static final java.lang.String Expect
```
    Indicates that particular server behaviors are required by the client.
    Example: Expect: 100-continue
    
    See Also:
    
    Constant Field Values
  - From
```
static final java.lang.String From
```
    The email address of the user making the request.
    Example: From: user@example.com
    
    See Also:
    
    Constant Field Values
  - Host
```
static final java.lang.String Host
```
    The domain name of the server (for virtual hosting), and the TCP port number on which the server is listening. The port number may be omitted if the port is the standard port for the service requested.
    Example: en.wikipedia.org
    
    See Also:
    
    Constant Field Values
  - IfMatch
```
static final java.lang.String IfMatch
```
    Only perform the action if the client supplied entity matches the same entity on the server. This is mainly for methods like PUT to only update a resource if it has not been modified since the user last updated it.
    Example: If-Match: "737060cd8c284d8af7ad3082f209582d"
    
    See Also:
    
    Constant Field Values
  - IfModifiedSince
```
static final java.lang.String IfModifiedSince
```
    Allows a 304 Not Modified to be returned if content is unchanged.
    Example: If-Modified-Since: Sat, 29 Oct 1994 19:43:31 GMT
    
    See Also:
    
    Constant Field Values
  - IfNoneMatch
```
static final java.lang.String IfNoneMatch
```
    Allows a 304 Not Modified to be returned if content is unchanged, see HTTP ETag.
    Example: If-None-Match: "737060cd8c284d8af7ad3082f209582d"
    
    See Also:
    
    Constant Field Values
  - IfRange
```
static final java.lang.String IfRange
```
    If the entity is unchanged, send me the part(s) that I am missing=""; otherwise, send me the entire new entity.
    Example: If-Range: "737060cd8c284d8af7ad3082f209582d"
    
    See Also:
    
    Constant Field Values
  - IfUnmodifiedSince
```
static final java.lang.String IfUnmodifiedSince
```
    Only send the response if the entity has not been modified since a specific time.
    Example: If-Unmodified-Since: Sat, 29 Oct 1994 19:43:31 GMT
    
    See Also:
    
    Constant Field Values
  - MaxForwards
```
static final java.lang.String MaxForwards
```
    Limit the number of times the message can be forwarded through proxies or gateways.
    Example: Max-Forwards: 10
    
    See Also:
    
    Constant Field Values
  - Origin
```
static final java.lang.String Origin
```
    Initiates a request for cross-origin resource sharing (asks server for an 'Access-Control-Allow-Origin' response field).
    Example: Origin: http://www.example-social-network.com
    
    See Also:
    
    Constant Field Values
  - Pragma
```
static final java.lang.String Pragma
```
    Implementation-specific fields that may have various effects anywhere along the request-response chain.
    Example: Pragma: no-cache
    
    See Also:
    
    Constant Field Values
  - ProxyAuthorization
```
static final java.lang.String ProxyAuthorization
```
    Authorization credentials for connecting to a proxy.
    Example: Proxy-Authorization: Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ==
    
    See Also:
    
    Constant Field Values
  - Range
```
static final java.lang.String Range
```
    Request only part of an entity. Bytes are numbered from 0.
    Example: Range: bytes=500-999
    
    See Also:
    
    Constant Field Values
  - Referer
```
static final java.lang.String Referer
```
    This is the address of the previous web page from which a link to the currently requested page was followed. (The word "referrer" has been misspelled in the RFC as well as in most implementations to the point that it has become standard usage and is considered correct terminology).
    Example: Referer: http://en.wikipedia.org/wiki/Main_Page
    
    See Also:
    
    Constant Field Values
  - TE
```
static final java.lang.String TE
```
    The transfer encodings the user agent is willing to accept: the same values as for the response header field Transfer-Encoding can be used, plus the "trailers" value (related to the "chunked" transfer method) to notify the server it expects to receive additional fields in the trailer after the last, zero-sized, chunk.
    Example: TE: trailers, deflate
    
    See Also:
    
    Constant Field Values
  - UserAgent
```
static final java.lang.String UserAgent
```
    The user agent string of the user agent.
    Example: User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:12.0) Gecko/20100101 Firefox/21.0
    
    See Also:
    
    Constant Field Values
  - Upgrade
```
static final java.lang.String Upgrade
```
    Ask the server to upgrade to another protocol.
    Example: Upgrade: HTTP/2.0, SHTTP/1.3, IRC/6.9, RTA/x11
    
    See Also:
    
    Constant Field Values
  - Via
```
static final java.lang.String Via
```
    Informs the server of proxies through which the request was sent.
    Example: Via: 1.0 fred, 1.1 example.com (Apache/1.1)
    
    See Also:
    
    Constant Field Values
  - Warning
```
static final java.lang.String Warning
```
    A general warning about possible problems with the entity body.
    Example: Warning: 199 Miscellaneous warning
    
    See Also:
    
    Constant Field Values

Interface HttpRequestHeader

Field Summary

Field Detail

Accept

AcceptCharset

AcceptEncoding

AcceptLanguage

AcceptDatetime

Authorization

CacheControl

Connection

Cookie

ContentLength

ContentMD5

ContentType

Date

Expect

From

Host

IfMatch

IfModifiedSince

IfNoneMatch

IfRange

IfUnmodifiedSince

MaxForwards

Origin

Pragma

ProxyAuthorization

Range

Referer

TE

UserAgent

Upgrade

Via

Warning