Filter (Java HTTP Server) - JDK 5 Documentation v6.0, Java 2 SDK 英文文档

Overview

Package

Class

Use

Tree

Index

Help

Java HTTP Server

PREV CLASS NEXT CLASS

FRAMES NO FRAMES

SUMMARY: NESTED | FIELD | CONSTR | METHOD

DETAIL: FIELD | CONSTR | METHOD

com.sun.net.httpserver
Class Filter

java.lang.Object
  com.sun.net.httpserver.Filter

public abstract class Filter
extends Object
extends Object

A filter used to pre- and post-process incoming requests. Pre-processing occurs before the application's exchange handler is invoked, and post-processing occurs after the exchange handler returns. Filters are organised in chains, and are associated with HttpContext instances.

Each Filter in the chain, invokes the next filter within its own doFilter() implementation. The final Filter in the chain invokes the applications exchange handler.

Since:: 1.6

Nested Class Summary

static class Filter.Chain
          a chain of filters associated with a HttpServer.

Constructor Summary

protected Filter()


Method Summary

abstract String description()
          returns a short description of this Filter

abstract void doFilter(HttpExchange exchange, Filter.Chain chain)
          Asks this filter to pre/post-process the given exchange.

Methods inherited from class java.lang.Object

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

Nested Class Summary
`static class`	`Filter.Chain` a chain of filters associated with a HttpServer.

Constructor Summary
`protected`	`Filter()`

Method Summary
`abstract String`	`description()` returns a short description of this Filter
`abstract void`	`doFilter(HttpExchange exchange, Filter.Chain chain)` Asks this filter to pre/post-process the given exchange.

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

Filter

protected Filter()

Method Detail

doFilter

public abstract void doFilter(HttpExchange exchange,
                              Filter.Chain chain)
                       throws IOException

Asks this filter to pre/post-process the given exchange. The filter can :-

examine or modify the request headers
filter the request body or the response body, by creating suitable filter streams and calling HttpExchange.setStreams(InputStream,OutputStream)
set attribute Objects in the exchange, which other filters or the exchange handler can access.
decide to either :-
1. invoke the next filter in the chain, by calling Filter.Chain.doFilter(HttpExchange)
2. terminate the chain of invocation, by not calling Filter.Chain.doFilter(HttpExchange)
if option 1. above taken, then when doFilter() returns all subsequent filters in the Chain have been called, and the response headers can be examined or modified.
if option 2. above taken, then this Filter must use the HttpExchange to send back an appropriate response

Parameters:: exchange - the HttpExchange to be filtered.; chain - the Chain which allows the next filter to be invoked.
Throws:: IOException - may be thrown by any filter module, and if caught, must be rethrown again.; NullPointerException - if either exchange or chain are null

description

public abstract String description()

returns a short description of this Filter

Returns:: a string describing the Filter