apache- httpcomponents-core4.4.6 学习笔记

概述


http协议的基础与核心工具类,使用HttpMessage(包含RequestLine/StatusLine、Header、HttpEntity)在HttpConnection上进行传输，
在传递消息之前或者之后可采用HttpRequestInterceptor/HttpResponseInterceptor对消息进行处理


HttpMessage—->消息基础,HttpRequest与HttpResponse均有此派生


generic-message = start-line
(message-header CRLF)
CRLF
[ message-body ]
start-line = Request-Line | Status-Line


HttpRequest—->请求

• BasicHttpEntityEnclosingRequest—->HttpEntityEnclosingRequest—->HttpRequest—->HttpMessage
• BasicHttpEntityEnclosingRequest—->BasicHttpRequest—->AbstractHttpMessage—->HttpMessage
  
  • HttpEntityEnclosingRequest提供请求中携带HttpEntity
  • AbstractHttpMessage提供Header相关方法支持
  • BasicHttpRequest提供RequestLine的支持
  • BasicHttpEntityEnclosingRequest拥有RequestLine/HttpEntity/Header

HttpEntity—->消息体(请求消息体或者响应消息体)

• 包含三种类型
  
  • 支持数据流方式,不可重复(简单理解为数据需要从别处获取)
  • 自我包含方式,可重复(简单理解为数据在内存)
  • 封装模式,支持上面两种
• InputStream getContent()
• writeTo(OutputStream outstream)
• InputStreamEntity—->AbstractHttpEntity—->HttpEntity
  
  • A streamed, non-repeatable entity that obtains its content from an {@link InputStream}.
• StringEntity—->AbstractHttpEntity—->HttpEntity
  
  • A self contained, repeatable entity that obtains its content from a {@link String}

HttpResponse—->响应

• BasicHttpResponse—->AbstractHttpMessage—->HttpResponse
  
  • BasicHttpResponse拥有StatusLine/HttpEntity/Header

HttpConnection—->传输通道

• DefaultBHttpClientConnection—->HttpClientConnection—->HttpConnection
• DefaultBHttpClientConnection—->BHttpConnectionBase—->HttpInetConnection—->HttpConnection
  
  • HttpConnection拥有服务端和客户端拥有的通用方法—-打开/关闭等
  • HttpClientConnection用于客户端连接,用于发送消息头、消息体、接收消息头、消息体
  • HttpInetConnection提供了在ip层支持
  • BHttpConnectionBase提供服务端与客户端连接的基本功能—-输入输出流，委托给SessionInputBufferImpl/SessionOutputBufferImpl
  • DefaultBHttpClientConnection在以上的基本上提供了消息的输出与解析工作,委托给HttpMessageWriter与HttpMessageParser

拦截器—->对请求预处理再发送,对响应预处理载返给调用者

• ImmutableHttpProcessor—->HttpProcessor—->HttpRequestInterceptor
• ImmutableHttpProcessor—->HttpProcessor—->HttpResponseInterceptor
  
  • ImmutableHttpProcessor基础的链式处理
• RequestDate—->HttpRequestInterceptor
  
  • 添加日期消息头

ConnPool—->连接池,管理共享的连接信息,相对于主机而言,主要有lease和release,有借有还

• BasicConnPool—->AbstractConnPool—->ConnPool
• BasicConnPool—->AbstractConnPool—->ConnPoolControl
• BasicPoolEntry—->PoolEntry
• RouteSpecificPool—->PoolEntry
  
  • ConnPool提供借与还的功能
  • AbstractConnPool提供实际创建PoolEntry功能,委托给RouteSpecificPool,
  • 最终通过org.apache.http.impl.pool.BasicConnPool.createEntry创建BasicPoolEntry,映射HttpHost与HttpClientConnection关系
  • 实际创建连接(final C conn = this.connFactory.create(route))
  • org.apache.http.pool.AbstractConnPool.getPoolEntryBlocking
  • 通过传入的连接工厂创建连接

HttpRequestExecutor—->基于阻塞的IO执行请求与响应

• preProcess—->利用HttpProcessor对请求进行预处理
• execute—->doSendRequest
  
  • 发送请求(委托HttpClientConnection先发送sendRequestHeader,然后发送sendRequestEntity)
  • 委托给DefaultHttpRequestWriter—->AbstractMessageWriter—->HttpMessageWriter进行预处理,最终调用DefaultBHttpClientConnection相关方法进行数据的最终传输
• execute—->doReceiveResponse
  
  • 接收请求(委托HttpClientConnection先接收receiveResponseHeader,然后接收receiveResponseEntity)
  • 委托给DefaultHttpResponseParser—->AbstractMessageParser—->HttpMessageParser进行预处理,最终调用DefaultBHttpClientConnection相关方法进行数据的最终传输
• postProcess—->利用HttpProcessor对响应进行预处理

测试

• example例子
  
  • examples.org.apache.http.examples.ElementalHttpGet
  • examples.org.apache.http.examples.ElementalHttpPost
  • examples.org.apache.http.examples.ElementalPoolingHttpGet
  • 实际创建连接(final C conn = this.connFactory.create(route))
    
    • org.apache.http.pool.AbstractConnPool.getPoolEntryBlocking
    • 通过传入的连接工厂创建连接