httpconnection.java

有关j2me的很好的例子可以研究一下

     * 400: The request could not be understood by the server due to malformed
     *   syntax.*/
    public static final int HTTP_BAD_REQUEST = 400;

    /**
     * 401: The request requires user authentication. The response
     *   MUST include a WWW-Authenticate header field  containing 
     *   a challenge applicable to the requested resource.
     */
    public static final int HTTP_UNAUTHORIZED = 401;

    /** 402: This code is reserved for future use. */
    public static final int HTTP_PAYMENT_REQUIRED = 402;

    /**
     * 403:  The server understood the request, but is refusing to fulfill it.
     *   Authorization will not help and the request SHOULD NOT be repeated.
     */
    public static final int HTTP_FORBIDDEN = 403;

    /**
     * 404: The server has not found anything matching the Request-URI. No
     *   indication is given of whether the condition is temporary or
     *   permanent.
     */
    public static final int HTTP_NOT_FOUND = 404;

    /** 
     * 405: The method specified in the Request-Line is not allowed for the
     *	resource identified by the Request-URI.
     */
    public static final int HTTP_BAD_METHOD = 405;

    /**
     * 406: The resource identified by the request is only capable of generating
     *   response entities which have content characteristics not acceptable
     *   according to the accept headers sent in the request.
     */
    public static final int HTTP_NOT_ACCEPTABLE = 406;

    /**
     * 407: This code is similar to 401 (Unauthorized), but indicates that the
     *	client must first authenticate itself with the proxy.
     */
    public static final int HTTP_PROXY_AUTH = 407;

    /**
     * 408: The client did not produce a request within the time that the server
     *   was prepared to wait. The client MAY repeat the request without
     *   modifications at any later time.
     */
    public static final int HTTP_CLIENT_TIMEOUT = 408;

    /**
     * 409: The request could not be completed due to a conflict
     *  with the current state of the resource.
     */
    public static final int HTTP_CONFLICT = 409;

    /**
     * 410: The requested resource is no longer available at the server and no
     *	forwarding address is known.
     */
    public static final int HTTP_GONE = 410;

    /**
     * 411: The server refuses to accept the request without a defined Content-
     *	Length.
     */
    public static final int HTTP_LENGTH_REQUIRED = 411;

    /**
     * 412: The precondition given in one or more of the request-header fields
     *	evaluated to false when it was tested on the server.
     */
    public static final int HTTP_PRECON_FAILED = 412;

    /** 
     * 413: The server is refusing to process a request because the request
     *	entity is larger than the server is willing or able to process.
     */
    public static final int HTTP_ENTITY_TOO_LARGE = 413;

    /**
     * 414: The server is refusing to service the request because 
     * the Request-URI is longer than the server is willing to interpret.
     */
    public static final int HTTP_REQ_TOO_LONG = 414;

    /**
     *  415: The server is refusing to service the request because the entity of
     *   the request is in a format not supported by the requested resource
     *   for the requested method.
     */
    public static final int HTTP_UNSUPPORTED_TYPE = 415;
    
    /**
     * 416: A server SHOULD return a response with this status code if a request
     *   included a Range request-header field , and none of
     *   the range-specifier values in this field overlap the current extent
     *   of the selected resource, and the request did not include an If-Range
     *   request-header field. 
     */
    public static final int HTTP_UNSUPPORTED_RANGE = 416;

    /**
     * 417: The expectation given in an Expect request-header field 
     *   could not be met by this server, or, if the server is a proxy,
     *   the server has unambiguous evidence that the request could not be met
     *   by the next-hop server.
     */
    public static final int HTTP_EXPECT_FAILED = 417;

    /** 5XX: server error */
    /**
     * 500: The server encountered an unexpected condition which prevented it
     *	from fulfilling the request.
     */
    public static final int HTTP_INTERNAL_ERROR = 500;

    /** 
     * 501: The server does not support the functionality required to
     * fulfill the request.
     */
    public static final int HTTP_NOT_IMPLEMENTED = 501;

    /**
     * 502: The server, while acting as a gateway or proxy, received an invalid
     *   response from the upstream server it accessed in attempting to
     *   fulfill the request.
     */
    public static final int HTTP_BAD_GATEWAY = 502;

    /**
     * 503: The server is currently unable to handle the request due to a
     *   temporary overloading or maintenance of the server.
     */
    public static final int HTTP_UNAVAILABLE = 503;

    /** 
     * 504: The server, while acting as a gateway or proxy, did not receive a
     *   timely response from the upstream server specified by the URI 
     *   or some other auxiliary server it needed
     *   to access in attempting to complete the request.
     */
    public static final int HTTP_GATEWAY_TIMEOUT = 504;

    /**
     * 505: The server does not support, or refuses to support,
     *   the HTTP protocol version that was used in the request message.
     */
    public static final int HTTP_VERSION = 505;

    /** 
     * Return a string representation of the URL for this connection.
     *
     * @return the string representation of the URL for this connection.
     */
    public String getURL();

    /**
     * Returns the protocol name of the URL of this
     * <code>HttpConnection</code>. e.g., http or https
     *
     * @return  the protocol of the URL of this <code>HttpConnection</code>.
     */
    public String getProtocol();

    /**
     * Returns the host information of the URL of
     * this <code>HttpConnection</code>. e.g. host name or IPv4 address
     *
     * @return  the host information of the URL of
     *  this <code>HttpConnection</code>.
     * <code>null</code> is returned if there is no host.
     */
    public String getHost();

    /**
     * Returns the file portion of the URL of this <code>HttpConnection</code>.
     *
     * @return  the file portion of the URL of this <code>HttpConnection</code>.
     * <code>null</code> is returned if there is no file.
     */
    public String getFile();

    /**
     * Returns the ref portion of the URL of this <code>HttpConnection</code>.
     * RFC2396 specifies the optional fragment identifier as the 
     * the text after the crosshatch (#) character in the URL.
     * This information  may be used by the user agent as additional
     * reference information after the resource is successfully retrieved.
     * The format and interpretation of the fragment identifier is dependent
     * on the media type[RFC2046] of the retrieved information.
     *
     * @return  the ref portion of the URL of this <code>HttpConnection</code>.
     * <code>null</code> is returned if there is no value.
     */
    public String getRef();

    /**
     * Returns the query portion of the URL of this <code>HttpConnection</code>.
     * RFC2396 defines the query component as the text after the last
     * question-mark (?) character in the URL.
     *
     * @return  the query portion of the URL of this
     * <code>HttpConnection</code>.
     * <code>null</code> is returned if there is no value.
     */
    public String getQuery();

    /**
     * Returns the network port number of the URL for this
     *  <code>HttpConnection</code>.
     *
     * @return  the network port number of the URL for this
     *  <code>HttpConnection</code>.
     * The default HTTP port number (80) is returned if there was
     * no port number in the string passed to <code>Connector.open</code>.
     */
    public int getPort();

    /**
     * Get the current request method. e.g. HEAD, GET, POST
     * The default value is GET.
     * @see #setRequestMethod
     * @return the HTTP request method
     */
    public String getRequestMethod();

    /**
     * Set the method for the URL request, one of:
     * <UL>
     *  <LI>GET
     *  <LI>POST
     *  <LI>HEAD
     * </UL> are legal, subject to protocol restrictions.  The default
     * method is GET.
     * @see #getRequestMethod
     * @param method the HTTP method
     * @exception IOException if the method cannot be reset or if
     *              the requested method isn't valid for HTTP.
     */
    public void setRequestMethod(String method) throws IOException;

    /**
     * Returns the value of the named general request property for this
     * connection.
     *
     * @see #setRequestProperty
     * @param key the keyword by which the request property is
     *  known (e.g., "accept").
     * @return  the value of the named general request property for this
     *           connection. If there is no key with the specified name then
     *		<CODE>null</CODE> is returned.
     */
    public String getRequestProperty(String key);

    /**
     * Sets the general request property. If a property with the key already
     * exists, overwrite its value with the new value.
     *
     * <p> NOTE: HTTP requires all request properties which can
     * legally have multiple instances with the same key
     * to use a comma-separated list syntax which enables multiple
     * properties to be appended into a single property.
     *
     * @see #getRequestProperty
     * @param   key     the keyword by which the request is known
     *                  (e.g., "<code>accept</code>").
     * @param   value   the value associated with it.
     * @exception IOException is thrown if the connection is in the
     *  connected state.
     */
    public void setRequestProperty(String key, String value) throws IOException;

    /**
     * Returns the HTTP response status code.
     * It parses responses like:
     * <PRE>
     * HTTP/1.0 200 OK
     * HTTP/1.0 401 Unauthorized
     * </PRE>
     * and extracts the ints 200 and 401 respectively.
     * from the response (i.e., the response is not valid HTTP).
     * @exception IOException if an error occurred connecting to the server.
     * @return the HTTP Status-Code or -1 if no status code can be discerned.
     */
    public int getResponseCode() throws IOException;

    /**
     * Gets the HTTP response message, if any, returned along with the
     * response code from a server.  From responses like:
     * <PRE>
     * HTTP/1.0 200 OK
     * HTTP/1.0 404 Not Found
     * </PRE>
     * Extracts the Strings "OK" and "Not Found" respectively.
     * Returns null if none could be discerned from the responses 
     * (the result was not valid HTTP).
     * @exception IOException if an error occurred connecting to the server.
     * @return the HTTP response message, or <code>null</code>
     */
    public String getResponseMessage() throws IOException;

    /**
     * Returns the value of the <code>expires</code> header field. 
     *
     * @return  the expiration date of the resource that this URL references,
     *          or 0 if not known. The value is the number of milliseconds since
     *          January 1, 1970 GMT.
     * @exception IOException if an error occurred connecting to the server.
     */
    public long getExpiration() throws IOException;

    /**
     * Returns the value of the <code>date</code> header field. 
     *
     * @return  the sending date of the resource that the URL references,
     *          or <code>0</code> if not known. The value returned is the
     *          number of milliseconds since January 1, 1970 GMT.
     * @exception IOException if an error occurred connecting to the server.
     */
    public long getDate() throws IOException;

    /**
     * Returns the value of the <code>last-modified</code> header field. 
     * The result is the number of milliseconds since January 1, 1970 GMT.
     *
     * @return  the date the resource referenced by this
     *          <code>HttpConnection</code> was last modified,
     *           or 0 if not known.
     * @exception IOException if an error occurred connecting to the server.
     */
    public long getLastModified() throws IOException;

    /**
     * Returns the value of the named header field.
     *
     * @param   name of a header field.
     * @return  the value of the named header field, or <code>null</code>
     *          if there is no such field in the header.
     * @exception IOException if an error occurred connecting to the server.
     */
    public String getHeaderField(String name) throws IOException;

    /**
     * Returns the value of the named field parsed as a number.
     * <p>
     * This form of <code>getHeaderField</code> exists because some 
     * connection types (e.g., <code>http-ng</code>) have pre-parsed 
     * headers. Classes for that connection type can override this method 
     * and short-circuit the parsing. 
     *
     * @param   name      the name of the header field.
     * @param   def   the default value.
     * @return  the value of the named field, parsed as an integer. The
     *          <code>def</code> value is returned if the field is
     *          missing or malformed.
     * @exception IOException if an error occurred connecting to the server.
     */
    public int getHeaderFieldInt(String name, int def) throws IOException;

    /**
     * Returns the value of the named field parsed as date.
     * The result is the number of milliseconds since January 1, 1970 GMT
     * represented by the named field. 
     * <p>
     * This form of <code>getHeaderField</code> exists because some 
     * connection types (e.g., <code>http-ng</code>) have pre-parsed 
     * headers. Classes for that connection type can override this method 
     * and short-circuit the parsing. 
     *
     * @param   name     the name of the header field.
     * @param   def   a default value.
     * @return  the value of the field, parsed as a date. The value of the
     *          <code>def</code> argument is returned if the field is
     *          missing or malformed.
     * @exception IOException if an error occurred connecting to the server.
     */
    public long getHeaderFieldDate(String name, long def) throws IOException;


    /**
     * Gets a header field value by index.
     *
     * @return the value of the  nth  header field or
     * <code>null</code> if the array index is out of range.
     * An empty String is returned if the field does not have a value.
     * @param n the index of the header field
     * @exception IOException if an error occurred connecting to the server.
     */
    public String getHeaderField(int n)  throws IOException;
    
    /**
     * Gets a header field key by index.
     *
     * @return the key of the nth header field or
     *  <code>null</code> if the array index is out of range.
     * @param n the index of the header field
     * @exception IOException if an error occurred connecting to the server.
     */
    public String getHeaderFieldKey(int n) throws IOException;
    
}