org.eclipse.jetty.servlets
类 GzipFilter

java.lang.Object
  org.eclipse.jetty.servlets.UserAgentFilter
      org.eclipse.jetty.servlets.GzipFilter

所有已实现的接口：

Filter

直接已知子类：

IncludableGzipFilter

public class GzipFilter
extends UserAgentFilter

GZIP Filter This filter will gzip or deflate the content of a response if:

• The filter is mapped to a matching path
• accept-encoding header is set to either gzip, deflate or a combination of those
• The response status code is >=200 and <300
• The content length is unknown or more than the minGzipSize initParameter or the minGzipSize is 0(default)
• The content-type is in the comma separated list of mimeTypes set in the mimeTypes initParameter or if no mimeTypes are defined the content-type is not "application/gzip"
• No content-encoding is specified by the resource

If both gzip and deflate are specified in the accept-encoding header, then gzip will be used.

Compressing the content can greatly improve the network bandwidth usage, but at a cost of memory and CPU cycles. If this filter is mapped for static content, then use of efficient direct NIO may be prevented, thus use of the gzip mechanism of the DefaultServlet is advised instead.

This filter extends UserAgentFilter and if the the initParameter excludedAgents is set to a comma separated list of user agents, then these agents will be excluded from gzip content.

Init Parameters:

 bufferSize                 The output buffer size. Defaults to 8192. Be careful as values <= 0 will lead to an 
                            IllegalArgumentException. 
                            See: GZIPOutputStream.GZIPOutputStream(java.io.OutputStream, int)
                            and: DeflaterOutputStream.DeflaterOutputStream(java.io.OutputStream, Deflater, int)
                      
 minGzipSize                Content will only be compressed if content length is either unknown or greater
                            than minGzipSize.
                      
 deflateCompressionLevel    The compression level used for deflate compression. (0-9).
                            See: Deflater.Deflater(int, boolean)
                            
 deflateNoWrap              The noWrap setting for deflate compression. Defaults to true. (true/false)
                            See: Deflater.Deflater(int, boolean)

 methods                    Comma separated list of HTTP methods to compress. If not set, only GET requests are compressed.
 
 mimeTypes                  Comma separated list of mime types to compress. See description above.
 
 excludedAgents             Comma separated list of user agents to exclude from compression. Does a 
                            String.contains(CharSequence) to check if the excluded agent occurs
                            in the user-agent header. If it does -> no compression
                            
 excludeAgentPatterns       Same as excludedAgents, but accepts regex patterns for more complex matching.
 
 excludePaths               Comma separated list of paths to exclude from compression. 
                            Does a String.startsWith(String) comparison to check if the path matches.
                            If it does match -> no compression. To match subpaths use excludePathPatterns
                            instead.
 
 excludePathPatterns        Same as excludePath, but accepts regex patterns for more complex matching.
 
 vary                       Set to the value of the Vary header sent with responses that could be compressed.  By default it is 
                            set to 'Vary: Accept-Encoding, User-Agent' since IE6 is excluded by default from the excludedAgents. 
                            If user-agents are not to be excluded, then this can be set to 'Vary: Accept-Encoding'.  Note also 
                            that shared caches may cache copies of a resource that is varied by User-Agent - one per variation of 
                            the User-Agent, unless the cache does some normalization of the UA string.
 

字段摘要

protected int	_bufferSize
protected ServletContext	_context
protected int	_deflateCompressionLevel
protected boolean	_deflateNoWrap
protected Set<Pattern>	_excludedAgentPatterns
protected Set<String>	_excludedAgents
protected Set<Pattern>	_excludedPathPatterns
protected Set<String>	_excludedPaths
protected Set<String>	_methods
protected Set<String>	_mimeTypes
protected int	_minGzipSize
protected String	_vary
static String	DEFLATE
static String	ETAG
static String	ETAG_DEFLATE
static String	ETAG_GZIP
static String	GZIP

构造方法摘要

GzipFilter()

方法摘要

protected void	configureWrappedResponse(CompressedResponseWrapper wrappedResponse)
protected CompressedResponseWrapper	createWrappedResponse(HttpServletRequest request, HttpServletResponse response, String compressionType)
void	destroy() Called by the web container to indicate to a filter that it is being taken out of service.
void	doFilter(ServletRequest req, ServletResponse res, FilterChain chain) The doFilter method of the Filter is called by the container each time a request/response pair is passed through the chain due to a client request for a resource at the end of the chain.
void	init(FilterConfig filterConfig) Called by the web container to indicate to a filter that it is being placed into service.

从类 org.eclipse.jetty.servlets.UserAgentFilter 继承的方法

getUserAgent, getUserAgent

从类 java.lang.Object 继承的方法

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

字段详细信息

GZIP

public static final String GZIP

另请参见：

常量字段值

ETAG_GZIP

public static final String ETAG_GZIP

另请参见：

常量字段值

DEFLATE

public static final String DEFLATE

另请参见：

常量字段值

ETAG_DEFLATE

public static final String ETAG_DEFLATE

另请参见：

常量字段值

ETAG

public static final String ETAG

另请参见：

常量字段值

_context

protected ServletContext _context

_mimeTypes

protected Set<String> _mimeTypes

_bufferSize

protected int _bufferSize

_minGzipSize

protected int _minGzipSize

_deflateCompressionLevel

protected int _deflateCompressionLevel

_deflateNoWrap

protected boolean _deflateNoWrap

_methods

protected final Set<String> _methods

_excludedAgents

protected Set<String> _excludedAgents

_excludedAgentPatterns

protected Set<Pattern> _excludedAgentPatterns

_excludedPaths

protected Set<String> _excludedPaths

_excludedPathPatterns

protected Set<Pattern> _excludedPathPatterns

_vary

protected String _vary

构造方法详细信息

GzipFilter

public GzipFilter()

方法详细信息

init

public void init(FilterConfig filterConfig)
          throws ServletException

从接口 Filter 复制的描述

Called by the web container to indicate to a filter that it is being placed into service.

The servlet container calls the init method exactly once after instantiating the filter. The init method must complete successfully before the filter is asked to do any filtering work.

The web container cannot place the filter into service if the init method either

1. Throws a ServletException
2. Does not return within a time period defined by the web container

指定者：

接口 Filter 中的 init

覆盖：

类 UserAgentFilter 中的 init

抛出：

ServletException

另请参见：

UserAgentFilter.init(javax.servlet.FilterConfig)

destroy

public void destroy()

从接口 Filter 复制的描述

Called by the web container to indicate to a filter that it is being taken out of service.

This method is only called once all threads within the filter's doFilter method have exited or after a timeout period has passed. After the web container calls this method, it will not call the doFilter method again on this instance of the filter.

This method gives the filter an opportunity to clean up any resources that are being held (for example, memory, file handles, threads) and make sure that any persistent state is synchronized with the filter's current state in memory.

指定者：

接口 Filter 中的 destroy

覆盖：

类 UserAgentFilter 中的 destroy

另请参见：

UserAgentFilter.destroy()

doFilter

public void doFilter(ServletRequest req,
                     ServletResponse res,
                     FilterChain chain)
              throws IOException,
                     ServletException

从接口 Filter 复制的描述

The doFilter method of the Filter is called by the container each time a request/response pair is passed through the chain due to a client request for a resource at the end of the chain. The FilterChain passed in to this method allows the Filter to pass on the request and response to the next entity in the chain.

A typical implementation of this method would follow the following pattern:

1. Examine the request
2. Optionally wrap the request object with a custom implementation to filter content or headers for input filtering
3. Optionally wrap the response object with a custom implementation to filter content or headers for output filtering
4. • Either invoke the next entity in the chain using the FilterChain object (chain.doFilter()),
   • or not pass on the request/response pair to the next entity in the filter chain to block the request processing
5. Directly set headers on the response after invocation of the next entity in the filter chain.

指定者：

接口 Filter 中的 doFilter

覆盖：

类 UserAgentFilter 中的 doFilter

抛出：

IOException

ServletException

另请参见：

UserAgentFilter.doFilter(javax.servlet.ServletRequest, javax.servlet.ServletResponse, javax.servlet.FilterChain)

createWrappedResponse

protected CompressedResponseWrapper createWrappedResponse(HttpServletRequest request,
                                                          HttpServletResponse response,
                                                          String compressionType)

configureWrappedResponse

protected void configureWrappedResponse(CompressedResponseWrapper wrappedResponse)