Java-HttpServletResponse-HttpServletResponseWrapper

//继承ServletResponse，发送回复信息，servlet容器创建一个HttpServletResponse对象，将它作为service函数的参数
public interface HttpServletResponse extends ServletResponse {

/**
* Adds the specified cookie to the response.  This method can be called
* multiple times to set more than one cookie.
* @param cookie the Cookie to return to the client
*/
//添加cookie
public void addCookie(Cookie cookie);

/**
* Returns a boolean indicating whether the named response header
* has already been set.
*/
//header中是否有name
public boolean containsHeader(String name);
/**
* Encodes the specified URL by including the session ID in it,
* or, if encoding is not needed, returns the URL unchanged.
* The implementation of this method includes the logic to
* determine whether the session ID needs to be encoded in the URL.
* For example, if the browser supports cookies, or session
* tracking is turned off, URL encoding is unnecessary.
* <p>For robust session tracking, all URLs emitted by a servlet
* should be run through this
* method.  Otherwise, URL rewriting cannot be used with browsers
* which do not support cookies.
* @param	url	the url to be encoded.
* @return		the encoded URL if encoding is needed;
* 			the unchanged URL otherwise.
*/
//url编码
public String encodeURL(String url);
/**
* Encodes the specified URL for use in the
* <code>sendRedirect</code> method or, if encoding is not needed,
* returns the URL unchanged.  The implementation of this method
* includes the logic to determine whether the session ID
* needs to be encoded in the URL.  Because the rules for making
* this determination can differ from those used to decide whether to
* encode a normal link, this method is separated from the
* <code>encodeURL</code> method.
* <p>All URLs sent to the <code>HttpServletResponse.sendRedirect</code>
* method should be run through this method.  Otherwise, URL
* rewriting cannot be used with browsers which do not support
* cookies.
* @param	url	the url to be encoded.
* @return		the encoded URL if encoding is needed;
* 			the unchanged URL otherwise.
* @see #sendRedirect
* @see #encodeUrl
*/
//URL编码跳转
public String encodeRedirectURL(String url);
/**
* Sends an error response to the client using the specified
* status.  The server defaults to creating the
* response to look like an HTML-formatted server error page
* containing the specified message, setting the content type
* to "text/html", leaving cookies and other headers unmodified.
* If an error-page declaration has been made for the web application
* corresponding to the status code passed in, it will be served back in
* preference to the suggested msg parameter.
* <p>If the response has already been committed, this method throws
* an IllegalStateException.
* After using this method, the response should be considered
* to be committed and should not be written to.
* @param	sc	the error status code
* @param	msg	the descriptive message
* @exception	IOException	If an input or output exception occurs
* @exception	IllegalStateException	If the response was committed
*/
//给客户端返回特定是错误状态码和信息
public void sendError(int sc, String msg) throws IOException;
/**
* Sends an error response to the client using the specified status
* code and clearing the buffer.
* <p>If the response has already been committed, this method throws
* an IllegalStateException.
* After using this method, the response should be considered
* to be committed and should not be written to.
* @param	sc	the error status code
* @exception	IOException	If an input or output exception occurs
* @exception	IllegalStateException	If the response was committed
*						before this method call
*/
//发送错误状态码，清空缓存
public void sendError(int sc) throws IOException;

/**
* Sends a temporary redirect response to the client using the
* specified redirect location URL.  This method can accept relative URLs;
* the servlet container must convert the relative URL to an absolute URL
* before sending the response to the client. If the location is relative
* without a leading '/' the container interprets it as relative to
* the current request URI. If the location is relative with a leading
* '/' the container interprets it as relative to the servlet container root.
*
* <p>If the response has already been committed, this method throws
* an IllegalStateException.
* After using this method, the response should be considered
* to be committed and should not be written to.
*
* @param		location	the redirect location URL
* @exception	IOException	If an input or output exception occurs
* @exception	IllegalStateException	If the response was committed or
if a partial URL is given and cannot be converted into a valid URL
*/
//跳转
public void sendRedirect(String location) throws IOException;
/**
* Sets a response header with the given name and
* date-value.  The date is specified in terms of
* milliseconds since the epoch.  If the header had already
* been set, the new value overwrites the previous one.  The
* <code>containsHeader</code> method can be used to test for the
* presence of a header before setting its value.
* @param	name	the name of the header to set
* @param	date	the assigned date value
* @see #containsHeader
* @see #addDateHeader
*/
//设置一个返回报文利用给定的name和date-value
public void setDateHeader(String name, long date);

/**
*
* Adds a response header with the given name and
* date-value.  The date is specified in terms of
* milliseconds since the epoch.  This method allows response headers
* to have multiple values.
*
* @param	name	the name of the header to set
* @param	date	the additional date value
*
* @see #setDateHeader
*/
//增加一个返回报文
public void addDateHeader(String name, long date);
/**
* Sets a response header with the given name and value.
* If the header had already been set, the new value overwrites the
* previous one.  The <code>containsHeader</code> method can be
* used to test for the presence of a header before setting its value.
* @param	name	the name of the header
* @param	value	the header value  If it contains octet string,
*		it should be encoded according to RFC 2047
*		(http://www.ietf.org/rfc/rfc2047.txt)
* @see #containsHeader
* @see #addHeader
*/
//设置一个返回头部报文，利用给定的name和value
public void setHeader(String name, String value);
/**
* Adds a response header with the given name and value.
* This method allows response headers to have multiple values.
* @param	name	the name of the header
* @param	value	the additional header value   If it contains
*		octet string, it should be encoded
*		according to RFC 2047
*		(http://www.ietf.org/rfc/rfc2047.txt)
* @see #setHeader
*/
//添加一个返回头部报文
public void addHeader(String name, String value);
/**
* Sets a response header with the given name and
* integer value.  If the header had already been set, the new value
* overwrites the previous one.  The <code>containsHeader</code>
* method can be used to test for the presence of a header before
* setting its value.
* @param	name	the name of the header
* @param	value	the assigned integer value
* @see #containsHeader
* @see #addIntHeader
*/
//
public void setIntHeader(String name, int value);

/**
* Adds a response header with the given name and
* integer value.  This method allows response headers to have multiple
* values.
*
* @param	name	the name of the header
* @param	value	the assigned integer value
*
* @see #setIntHeader
*/
public void addIntHeader(String name, int value);
/**
* Sets the status code for this response.  This method is used to
* set the return status code when there is no error (for example,
* for the status codes SC_OK or SC_MOVED_TEMPORARILY).  If there
* is an error, and the caller wishes to invoke an error-page defined
* in the web application, the <code>sendError</code> method should be used
* instead.
* <p> The container clears the buffer and sets the Location header, preserving
* cookies and other headers.
*
* @param	sc	the status code
*
* @see #sendError
*/
//设置状态
public void setStatus(int sc);

/**
* @deprecated As of version 2.1, due to ambiguous meaning of the
* message parameter. To set a status code
* use <code>setStatus(int)</code>, to send an error with a description
* use <code>sendError(int, String)</code>.
* Sets the status code and message for this response.
* @param	sc	the status code
* @param	sm	the status message
*/
public void setStatus(int sc, String sm);

/*
* Server status codes; see RFC 2068.
*/
/**
* Status code (100) indicating the client can continue.
*/
//状态码

public static final int SC_CONTINUE = 100;
/**
* Status code (101) indicating the server is switching protocols
* according to Upgrade header.
*/
public static final int SC_SWITCHING_PROTOCOLS = 101;
/**
* Status code (200) indicating the request succeeded normally.
*/
public static final int SC_OK = 200;
/**
* Status code (201) indicating the request succeeded and created
* a new resource on the server.
*/
public static final int SC_CREATED = 201;
/**
* Status code (202) indicating that a request was accepted for
* processing, but was not completed.
*/
public static final int SC_ACCEPTED = 202;
/**
* Status code (203) indicating that the meta information presented
* by the client did not originate from the server.
*/
public static final int SC_NON_AUTHORITATIVE_INFORMATION = 203;
/**
* Status code (204) indicating that the request succeeded but that
* there was no new information to return.
*/
public static final int SC_NO_CONTENT = 204;
/**
* Status code (205) indicating that the agent <em>SHOULD</em> reset
* the document view which caused the request to be sent.
*/
public static final int SC_RESET_CONTENT = 205;
/**
* Status code (206) indicating that the server has fulfilled
* the partial GET request for the resource.
*/
public static final int SC_PARTIAL_CONTENT = 206;
/**
* Status code (300) indicating that the requested resource
* corresponds to any one of a set of representations, each with
* its own specific location.
*/
public static final int SC_MULTIPLE_CHOICES = 300;
/**
* Status code (301) indicating that the resource has permanently
* moved to a new location, and that future references should use a
* new URI with their requests.
*/
public static final int SC_MOVED_PERMANENTLY = 301;
/**
* Status code (302) indicating that the resource has temporarily
* moved to another location, but that future references should
* still use the original URI to access the resource.
*
* This definition is being retained for backwards compatibility.
* SC_FOUND is now the preferred definition.
*/
public static final int SC_MOVED_TEMPORARILY = 302;
/**
* Status code (302) indicating that the resource reside
* temporarily under a different URI. Since the redirection might
* be altered on occasion, the client should continue to use the
* Request-URI for future requests.(HTTP/1.1) To represent the
* status code (302), it is recommended to use this variable.
*/
public static final int SC_FOUND = 302;
/**
* Status code (303) indicating that the response to the request
* can be found under a different URI.
*/
public static final int SC_SEE_OTHER = 303;
/**
* Status code (304) indicating that a conditional GET operation
* found that the resource was available and not modified.
*/
public static final int SC_NOT_MODIFIED = 304;
/**
* Status code (305) indicating that the requested resource
* <em>MUST</em> be accessed through the proxy given by the
* <code><em>Location</em></code> field.
*/
public static final int SC_USE_PROXY = 305;
/**
* Status code (307) indicating that the requested resource
* resides temporarily under a different URI. The temporary URI
* <em>SHOULD</em> be given by the <code><em>Location</em></code>
* field in the response.
*/
public static final int SC_TEMPORARY_REDIRECT = 307;
/**
* Status code (400) indicating the request sent by the client was
* syntactically incorrect.
*/
public static final int SC_BAD_REQUEST = 400;
/**
* Status code (401) indicating that the request requires HTTP
* authentication.
*/
public static final int SC_UNAUTHORIZED = 401;
/**
* Status code (402) reserved for future use.
*/
public static final int SC_PAYMENT_REQUIRED = 402;
/**
* Status code (403) indicating the server understood the request
* but refused to fulfill it.
*/
public static final int SC_FORBIDDEN = 403;
/**
* Status code (404) indicating that the requested resource is not
* available.
*/
public static final int SC_NOT_FOUND = 404;
/**
* Status code (405) indicating that the method specified in the
* <code><em>Request-Line</em></code> is not allowed for the resource
* identified by the <code><em>Request-URI</em></code>.
*/
public static final int SC_METHOD_NOT_ALLOWED = 405;
/**
* Status code (406) indicating that 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 SC_NOT_ACCEPTABLE = 406;
/**
* Status code (407) indicating that the client <em>MUST</em> first
* authenticate itself with the proxy.
*/
public static final int SC_PROXY_AUTHENTICATION_REQUIRED = 407;
/**
* Status code (408) indicating that the client did not produce a
* request within the time that the server was prepared to wait.
*/
public static final int SC_REQUEST_TIMEOUT = 408;
/**
* Status code (409) indicating that the request could not be
* completed due to a conflict with the current state of the
* resource.
*/
public static final int SC_CONFLICT = 409;
/**
* Status code (410) indicating that the resource is no longer
* available at the server and no forwarding address is known.
* This condition <em>SHOULD</em> be considered permanent.
*/
public static final int SC_GONE = 410;
/**
* Status code (411) indicating that the request cannot be handled
* without a defined <code><em>Content-Length</em></code>.
*/
public static final int SC_LENGTH_REQUIRED = 411;
/**
* Status code (412) indicating that 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 SC_PRECONDITION_FAILED = 412;

/**
* Status code (413) indicating that the server is refusing to process
* the request because the request entity is larger than the server is
* willing or able to process.
*/

public static final int SC_REQUEST_ENTITY_TOO_LARGE = 413;

/**
* Status code (414) indicating that the server is refusing to service
* the request because the <code><em>Request-URI</em></code> is longer
* than the server is willing to interpret.
*/

public static final int SC_REQUEST_URI_TOO_LONG = 414;

/**
* Status code (415) indicating that 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 SC_UNSUPPORTED_MEDIA_TYPE = 415;

/**
* Status code (416) indicating that the server cannot serve the
* requested byte range.
*/

public static final int SC_REQUESTED_RANGE_NOT_SATISFIABLE = 416;

/**
* Status code (417) indicating that the server could not meet the
* expectation given in the Expect request header.
*/

public static final int SC_EXPECTATION_FAILED = 417;

/**
* Status code (500) indicating an error inside the HTTP server
* which prevented it from fulfilling the request.
*/

public static final int SC_INTERNAL_SERVER_ERROR = 500;

/**
* Status code (501) indicating the HTTP server does not support
* the functionality needed to fulfill the request.
*/

public static final int SC_NOT_IMPLEMENTED = 501;

/**
* Status code (502) indicating that the HTTP server received an
* invalid response from a server it consulted when acting as a
* proxy or gateway.
*/

public static final int SC_BAD_GATEWAY = 502;

/**
* Status code (503) indicating that the HTTP server is
* temporarily overloaded, and unable to handle the request.
*/

public static final int SC_SERVICE_UNAVAILABLE = 503;

/**
* Status code (504) indicating that the server did not receive
* a timely response from the upstream server while acting as
* a gateway or proxy.
*/

public static final int SC_GATEWAY_TIMEOUT = 504;

/**
* Status code (505) indicating that the server does not support
* or refuses to support the HTTP protocol version that was used
* in the request message.
*/

public static final int SC_HTTP_VERSION_NOT_SUPPORTED = 505;
}

public class HttpServletResponseWrapper extends ServletResponseWrapper implements HttpServletResponse {

/**
* Constructs a response adaptor wrapping the given response.
* @throws java.lang.IllegalArgumentException if the response is null
*/
public HttpServletResponseWrapper(HttpServletResponse response) {
super(response);
}

private HttpServletResponse _getHttpServletResponse() {
return (HttpServletResponse) super.getResponse();
}

/**
* The default behavior of this method is to call addCookie(Cookie cookie)
* on the wrapped response object.
*/
public void addCookie(Cookie cookie) {
this._getHttpServletResponse().addCookie(cookie);
}

/**
* The default behavior of this method is to call containsHeader(String name)
* on the wrapped response object.
*/

public boolean containsHeader(String name) {
return this._getHttpServletResponse().containsHeader(name);
}

/**
* The default behavior of this method is to call encodeURL(String url)
* on the wrapped response object.
*/
public String encodeURL(String url) {
return this._getHttpServletResponse().encodeURL(url);
}

/**
* The default behavior of this method is to return encodeRedirectURL(String url)
* on the wrapped response object.
*/
public String encodeRedirectURL(String url) {
return this._getHttpServletResponse().encodeRedirectURL(url);
}

/**
* The default behavior of this method is to call encodeUrl(String url)
* on the wrapped response object.
*/
public String encodeUrl(String url) {
return this._getHttpServletResponse().encodeUrl(url);
}

/**
* The default behavior of this method is to return encodeRedirectUrl(String url)
* on the wrapped response object.
*/
public String encodeRedirectUrl(String url) {
return this._getHttpServletResponse().encodeRedirectUrl(url);
}

/**
* The default behavior of this method is to call sendError(int sc, String msg)
* on the wrapped response object.
*/
public void sendError(int sc, String msg) throws IOException {
this._getHttpServletResponse().sendError(sc, msg);
}

/**
* The default behavior of this method is to call sendError(int sc)
* on the wrapped response object.
*/

public void sendError(int sc) throws IOException {
this._getHttpServletResponse().sendError(sc);
}

/**
* The default behavior of this method is to return sendRedirect(String location)
* on the wrapped response object.
*/
public void sendRedirect(String location) throws IOException {
this._getHttpServletResponse().sendRedirect(location);
}

/**
* The default behavior of this method is to call setDateHeader(String name, long date)
* on the wrapped response object.
*/
public void setDateHeader(String name, long date) {
this._getHttpServletResponse().setDateHeader(name, date);
}

/**
* The default behavior of this method is to call addDateHeader(String name, long date)
* on the wrapped response object.
*/
public void addDateHeader(String name, long date) {
this._getHttpServletResponse().addDateHeader(name, date);
}

/**
* The default behavior of this method is to return setHeader(String name, String value)
* on the wrapped response object.
*/
public void setHeader(String name, String value) {
this._getHttpServletResponse().setHeader(name, value);
}

/**
* The default behavior of this method is to return addHeader(String name, String value)
* on the wrapped response object.
*/
public void addHeader(String name, String value) {
this._getHttpServletResponse().addHeader(name, value);
}

/**
* The default behavior of this method is to call setIntHeader(String name, int value)
* on the wrapped response object.
*/
public void setIntHeader(String name, int value) {
this._getHttpServletResponse().setIntHeader(name, value);
}

/**
* The default behavior of this method is to call addIntHeader(String name, int value)
* on the wrapped response object.
*/
public void addIntHeader(String name, int value) {
this._getHttpServletResponse().addIntHeader(name, value);
}

/**
* The default behavior of this method is to call setStatus(int sc)
* on the wrapped response object.
*/

public void setStatus(int sc) {
this._getHttpServletResponse().setStatus(sc);
}

/**
* The default behavior of this method is to call setStatus(int sc, String sm)
* on the wrapped response object.
*/
public void setStatus(int sc, String sm) {
this._getHttpServletResponse().setStatus(sc, sm);
}

}