HttpServletRequest (Java EE 5 SDK)

javax.servlet.http Interface HttpServletRequest

所有父接口:

ServletRequest

所有已知实现子孙类:

HttpServletRequestWrapper

public interface HttpServletRequest

extends ServletRequest

Extends the ServletRequest interface to provide request information for HTTP servlets.

The servlet container creates an HttpServletRequest object and passes it as an argument to the servlet's service methods (doGet, doPost, etc).

作者:

Various

BASIC_AUTH

static final String BASIC_AUTH

String identifier for Basic authentication. Value "BASIC"

另请参见:

常量字段

FORM_AUTH

static final String FORM_AUTH

String identifier for Form authentication. Value "FORM"

另请参见:

常量字段

CLIENT_CERT_AUTH

static final String CLIENT_CERT_AUTH

String identifier for Client Certificate authentication. Value "CLIENT_CERT"

另请参见:

常量字段

DIGEST_AUTH

static final String DIGEST_AUTH

String identifier for Digest authentication. Value "DIGEST"

另请参见:

常量字段

getAuthType

String getAuthType()

Returns the name of the authentication scheme used to protect the servlet. All servlet containers support basic, form and client certificate authentication, and may additionally support digest authentication. If the servlet is not authenticated null is returned.

Same as the value of the CGI variable AUTH_TYPE.

返回:

one of the static members BASIC_AUTH, FORM_AUTH, CLIENT_CERT_AUTH, DIGEST_AUTH (suitable for == comparison) or the container-specific string indicating the authentication scheme, or null if the request was not authenticated.

getCookies

Cookie[] getCookies()

Returns an array containing all of the Cookie objects the client sent with this request. This method returns null if no cookies were sent.

返回:

an array of all the Cookies included with this request, or null if the request has no cookies

getDateHeader

long getDateHeader(String name)

Returns the value of the specified request header as a long value that represents a Date object. Use this method with headers that contain dates, such as If-Modified-Since.

The date is returned as the number of milliseconds since January 1, 1970 GMT. The header name is case insensitive.

If the request did not have a header of the specified name, this method returns -1. If the header can't be converted to a date, the method throws an IllegalArgumentException.

参数:

name - a String specifying the name of the header

返回:

a long value representing the date specified in the header expressed as the number of milliseconds since January 1, 1970 GMT, or -1 if the named header was not included with the request

抛出异常:

IllegalArgumentException - If the header value can't be converted to a date

getHeader

String getHeader(String name)

Returns the value of the specified request header as a String. If the request did not include a header of the specified name, this method returns null. If there are multiple headers with the same name, this method returns the first head in the request. The header name is case insensitive. You can use this method with any request header.

参数:

name - a String specifying the header name

返回:

a String containing the value of the requested header, or null if the request does not have a header of that name

getHeaders

Enumeration getHeaders(String name)

Returns all the values of the specified request header as an Enumeration of String objects.

Some headers, such as Accept-Language can be sent by clients as several headers each with a different value rather than sending the header as a comma separated list.

If the request did not include any headers of the specified name, this method returns an empty Enumeration. The header name is case insensitive. You can use this method with any request header.

参数:

name - a String specifying the header name

返回:

an Enumeration containing the values of the requested header. If the request does not have any headers of that name return an empty enumeration. If the container does not allow access to header information, return null

getHeaderNames

Enumeration getHeaderNames()

Returns an enumeration of all the header names this request contains. If the request has no headers, this method returns an empty enumeration.

Some servlet containers do not allow servlets to access headers using this method, in which case this method returns null

返回:

an enumeration of all the header names sent with this request; if the request has no headers, an empty enumeration; if the servlet container does not allow servlets to use this method, null

getIntHeader

int getIntHeader(String name)

Returns the value of the specified request header as an int. If the request does not have a header of the specified name, this method returns -1. If the header cannot be converted to an integer, this method throws a NumberFormatException.

The header name is case insensitive.

参数:

name - a String specifying the name of a request header

返回:

an integer expressing the value of the request header or -1 if the request doesn't have a header of this name

抛出异常:

NumberFormatException - If the header value can't be converted to an int

getMethod

String getMethod()

Returns the name of the HTTP method with which this request was made, for example, GET, POST, or PUT. Same as the value of the CGI variable REQUEST_METHOD.

返回:

a String specifying the name of the method with which this request was made

getPathInfo

String getPathInfo()

Returns any extra path information associated with the URL the client sent when it made this request. The extra path information follows the servlet path but precedes the query string and will start with a "/" character.

This method returns null if there was no extra path information.

Same as the value of the CGI variable PATH_INFO.

返回:

a String, decoded by the web container, specifying extra path information that comes after the servlet path but before the query string in the request URL; or null if the URL does not have any extra path information

getPathTranslated

String getPathTranslated()

Returns any extra path information after the servlet name but before the query string, and translates it to a real path. Same as the value of the CGI variable PATH_TRANSLATED.

If the URL does not have any extra path information, this method returns null or the servlet container cannot translate the virtual path to a real path for any reason (such as when the web application is executed from an archive). The web container does not decode this string.

返回:

a String specifying the real path, or null if the URL does not have any extra path information

getContextPath

String getContextPath()

Returns the portion of the request URI that indicates the context of the request. The context path always comes first in a request URI. The path starts with a "/" character but does not end with a "/" character. For servlets in the default (root) context, this method returns "". The container does not decode this string.

It is possible that a servlet container may match a context by more than one context path. In such cases this method will return the actual context path used by the request and it may differ from the path returned by the ServletContext.getContextPath() method. The context path returned by ServletContext.getContextPath() should be considered as the prime or preferred context path of the application.

返回:

a String specifying the portion of the request URI that indicates the context of the request

另请参见:

ServletContext.getContextPath()

getQueryString

String getQueryString()

Returns the query string that is contained in the request URL after the path. This method returns null if the URL does not have a query string. Same as the value of the CGI variable QUERY_STRING.

返回:

a String containing the query string or null if the URL contains no query string. The value is not decoded by the container.

getRemoteUser

String getRemoteUser()

Returns the login of the user making this request, if the user has been authenticated, or null if the user has not been authenticated. Whether the user name is sent with each subsequent request depends on the browser and type of authentication. Same as the value of the CGI variable REMOTE_USER.

返回:

a String specifying the login of the user making this request, or null if the user login is not known

isUserInRole

boolean isUserInRole(String role)

Returns a boolean indicating whether the authenticated user is included in the specified logical "role". Roles and role membership can be defined using deployment descriptors. If the user has not been authenticated, the method returns false.

参数:

role - a String specifying the name of the role

返回:

a boolean indicating whether the user making this request belongs to a given role; false if the user has not been authenticated

getUserPrincipal

Principal getUserPrincipal()

Returns a java.security.Principal object containing the name of the current authenticated user. If the user has not been authenticated, the method returns null.

返回:

a java.security.Principal containing the name of the user making this request; null if the user has not been authenticated

getRequestedSessionId

String getRequestedSessionId()

Returns the session ID specified by the client. This may not be the same as the ID of the current valid session for this request. If the client did not specify a session ID, this method returns null.

返回:

a String specifying the session ID, or null if the request did not specify a session ID

另请参见:

isRequestedSessionIdValid()

getRequestURI

String getRequestURI()

Returns the part of this request's URL from the protocol name up to the query string in the first line of the HTTP request. The web container does not decode this String. For example:

First line of HTTP request	Returned Value
POST /some/path.html HTTP/1.1		/some/path.html
GET http://foo.bar/a.html HTTP/1.0		/a.html
HEAD /xyz?a=b HTTP/1.1		/xyz

To reconstruct an URL with a scheme and host, use HttpUtils.getRequestURL(javax.servlet.http.HttpServletRequest).

返回:

a String containing the part of the URL from the protocol name up to the query string

另请参见:

HttpUtils.getRequestURL(javax.servlet.http.HttpServletRequest)

getRequestURL

StringBuffer getRequestURL()

Reconstructs the URL the client used to make the request. The returned URL contains a protocol, server name, port number, and server path, but it does not include query string parameters.

If this request has been forwarded using RequestDispatcher.forward(javax.servlet.ServletRequest, javax.servlet.ServletResponse), the server path in the reconstructed URL must reflect the path used to obtain the RequestDispatcher, and not the server path specified by the client.

Because this method returns a StringBuffer, not a string, you can modify the URL easily, for example, to append query parameters.

This method is useful for creating redirect messages and for reporting errors.

返回:

a StringBuffer object containing the reconstructed URL

getServletPath

String getServletPath()

Returns the part of this request's URL that calls the servlet. This path starts with a "/" character and includes either the servlet name or a path to the servlet, but does not include any extra path information or a query string. Same as the value of the CGI variable SCRIPT_NAME.

This method will return an empty string ("") if the servlet used to process this request was matched using the "/*" pattern.

返回:

a String containing the name or path of the servlet being called, as specified in the request URL, decoded, or an empty string if the servlet used to process the request is matched using the "/*" pattern.

getSession

HttpSession getSession(boolean create)

Returns the current HttpSession associated with this request or, if there is no current session and create is true, returns a new session.

If create is false and the request has no valid HttpSession, this method returns null.

To make sure the session is properly maintained, you must call this method before the response is committed. If the container is using cookies to maintain session integrity and is asked to create a new session when the response is committed, an IllegalStateException is thrown.

参数:

create - true to create a new session for this request if necessary; false to return null if there's no current session

返回:

the HttpSession associated with this request or null if create is false and the request has no valid session

另请参见:

getSession()

getSession

HttpSession getSession()

Returns the current session associated with this request, or if the request does not have a session, creates one.

返回:

the HttpSession associated with this request

另请参见:

getSession(boolean)

isRequestedSessionIdValid

boolean isRequestedSessionIdValid()

Checks whether the requested session ID is still valid.

If the client did not specify any session ID, this method returns false.

返回:

true if this request has an id for a valid session in the current session context; false otherwise

另请参见:

getRequestedSessionId(), getSession(boolean), HttpSessionContext

isRequestedSessionIdFromCookie

boolean isRequestedSessionIdFromCookie()

Checks whether the requested session ID came in as a cookie.

返回:

true if the session ID came in as a cookie; otherwise, false

另请参见:

getSession(boolean)

isRequestedSessionIdFromURL

boolean isRequestedSessionIdFromURL()

Checks whether the requested session ID came in as part of the request URL.

返回:

true if the session ID came in as part of a URL; otherwise, false

另请参见:

getSession(boolean)

isRequestedSessionIdFromUrl

boolean isRequestedSessionIdFromUrl()

Deprecated. As of Version 2.1 of the Java Servlet API, use isRequestedSessionIdFromURL() instead.

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