org.eclipse.jetty.servlets
类 UserAgentFilter

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

所有已实现的接口：

Filter

直接已知子类：

GzipFilter

public class UserAgentFilter
extends Object
implements Filter

User Agent Filter.

This filter allows efficient matching of user agent strings for downstream or extended filters to use for browser specific logic.

The filter is configured with the following init parameters:

attribute

If set, then the request attribute of this name is set with the matched user agent string

cacheSize

The size of the user-agent cache, used to avoid reparsing of user agent strings. The entire cache is flushed when this size is reached

userAgent

A regex Pattern to extract the essential elements of the user agent. The concatenation of matched pattern groups is used as the user agent name

An example value for pattern is (?:Mozilla[^\(]*\(compatible;\s*+([^;]*);.*)|(?:.*?([^\s]+/[^\s]+).*). These two pattern match the common compatibility user-agent strings and extract the real user agent, failing that, the first element of the agent string is returned.

构造方法摘要

UserAgentFilter()

方法摘要

void	destroy() Called by the web container to indicate to a filter that it is being taken out of service.
void	doFilter(ServletRequest request, ServletResponse response, 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.
String	getUserAgent(ServletRequest request)
String	getUserAgent(String ua) Get UserAgent.
void	init(FilterConfig filterConfig) Called by the web container to indicate to a filter that it is being placed into service.

从类 java.lang.Object 继承的方法

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

构造方法详细信息

UserAgentFilter

public UserAgentFilter()

方法详细信息

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

doFilter

public void doFilter(ServletRequest request,
                     ServletResponse response,
                     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

抛出：

IOException

ServletException

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

抛出：

ServletException

getUserAgent

public String getUserAgent(ServletRequest request)

getUserAgent

public String getUserAgent(String ua)

Get UserAgent. The configured agent patterns are used to match against the passed user agent string. If any patterns match, the concatenation of pattern groups is returned as the user agent string. Match results are cached.

参数：

ua - A user agent string

返回：

The matched pattern groups or the original user agent string