我对httpclient 4.2.2和用户名/密码代理有问题。
httpclient的工作方式如下：
列表项
发送不带代理的请求（但是我为每个请求设置代理参数）
从squid获取响应，错误为407
用代理材料发送请求
这是一种非常奇怪的行为，是否可以在每个请求中添加有关代理的信息？我试过在每个请求中添加硬编码的“代理授权”头，它工作得很好，为什么httpclient不能这样做？
Java代码
DefaultHttpClient httpClient = new DefaultHttpClient();
httpClient.getParams().setParameter(PROTOCOL_VERSION, HTTP_1_1);
...
String proxyServer = getProxyServer();
int proxyPort = getProxyPort();
List<String> authpref = new ArrayList<String>();
authpref.add(AuthPolicy.BASIC);
httpClient.getParams().setParameter(AuthPNames.PROXY_AUTH_PREF, authpref);
String proxyUser = getProxyUser();
String proxyPassword = getProxyPassword();
CredentialsProvider credsProvider = httpClient.getCredentialsProvider();
credsProvider.setCredentials(new AuthScope(proxyServer, proxyPort), new UsernamePasswordCredentials(proxyUser, proxyPassword));
httpClient.setCredentialsProvider(credsProvider);
HttpHost proxy = new HttpHost(proxyServer, proxyPort, (proxyServer.indexOf("https") != 0) ? "http" : "https");
httpClient.getParams().setParameter(ConnRoutePNames.DEFAULT_PROXY, proxy);
...
HttpPut put = new HttpPut(url);
/*** hardcoded header ***/
//put.addHeader("Proxy-Authorization", "Basic eHRlbmR4LmRuZXByOnF3ZXJ0eQ==");
/*** hardcoded header ***/
put.setEntity(entity);
httpClient.execute(put);
httpClient.getConnectionManager().shutdown();
[DefaultClientConnection] Sending request: PUT http://172.26.27.22:8080/myapp/rest/2/3/29/image1.jpg HTTP/1.1
[headers] >> PUT http://172.26.27.22:8080/myapp/rest/2/3/29/image1.jpg HTTP/1.1
[headers] >> Authorization: Basic eGRldjo0YTFmNmMwOTgyYWRkMWQ0NDg1YjRhMGE4YWMxY2JjMWNiMTA0ODc1
[headers] >> Content-Length: 2
[headers] >> Host: 172.26.27.22:8080
[headers] >> Proxy-Connection: Keep-Alive
[headers] >> User-Agent: Apache-HttpClient/4.2.2 (java 1.5)
[DefaultClientConnection] Receiving response: HTTP/1.0 407 Proxy Authentication Required
[headers] << HTTP/1.0 407 Proxy Authentication Required
[headers] << Server: squid/2.7.STABLE8
[headers] << Date: Thu, 08 Nov 2012 10:09:49 GMT
[headers] << Content-Type: text/html
[headers] << Content-Length: 1431
[headers] << X-Squid-Error: ERR_CACHE_ACCESS_DENIED 0
[headers] << Proxy-Authenticate: Basic realm="Please, enter username and password"
[headers] << X-Cache: MISS from 172.26.27.94
[headers] << X-Cache-Lookup: NONE from 172.26.27.94:3128
[headers] << Via: 1.0 172.26.27.94:3128 (squid/2.7.STABLE8)
[headers] << Connection: close
[DefaultHttpClient] Authentication required
[DefaultHttpClient] 172.26.27.94:3128 requested authentication
[ProxyAuthenticationStrategy] Authentication schemes in the order of preference: [Basic]
[DefaultHttpClient] Selected authentication options: [BASIC]
[DefaultClientConnection] Connection 0.0.0.0:63344<->172.26.27.94:3128 closed
[DefaultClientConnectionOperator] Connecting to 172.26.27.94:3128
[RequestAddCookies] CookieSpec selected: best-match
[RequestAuthCache] Re-using cached 'basic' auth scheme for http://172.26.27.22:8080
[RequestAuthCache] No credentials for preemptive authentication
[RequestProxyAuthentication] Proxy auth state: CHALLENGED
[RequestProxyAuthentication] Generating response to an authentication challenge using basic scheme
[DefaultHttpClient] Attempt 2 to execute request
[DefaultClientConnection] Sending request: PUT http://172.26.27.22:8080/myapp/rest/2/3/29/image1.jpg HTTP/1.1
[headers] >> PUT http://172.26.27.22:8080/myapp/rest/2/3/29/image1.jpg HTTP/1.1
[headers] >> Authorization: Basic eGRldjo0YTFmNmMwOTgyYWRkMWQ0NDg1YjRhMGE4YWMxY2JjMWNiMTA0ODc1
[headers] >> Content-Length: 2
[headers] >> Host: 172.26.27.22:8080
[headers] >> Proxy-Connection: Keep-Alive
[headers] >> User-Agent: Apache-HttpClient/4.2.2 (java 1.5)
[headers] >> Proxy-Authorization: Basic eHRlbmR4LmRuZXByOnF3ZXJ0eQ==
[DefaultClientConnection] Receiving response: HTTP/1.0 201 Created
[headers] << HTTP/1.0 201 Created
[headers] << Content-Length: 0
[headers] << Date: Thu, 08 Nov 2012 10:09:49 GMT
[headers] << X-Cache: MISS from 172.26.27.94
[headers] << X-Cache-Lookup: MISS from 172.26.27.94:3128
[headers] << Via: 1.1 172.26.27.94:3128 (squid/2.7.STABLE8)
[headers] << Connection: keep-alive
[headers] << Proxy-Connection: keep-alive
鱿鱼原木
1352370666.778 0 172.26.27.94 TCP_DENIED/407 1870 PUT http://172.26.27.22:8080/myapp/rest/2/3/29/image1.jpg - NONE/- text/html
1352370671.429 8 172.26.27.94 TCP_MISS/201 282 PUT http://172.26.27.22:8080/myapp/rest/2/3/29/image1.jpg proxyuser DIRECT/172.26.27.22 -
1352370671.474 0 172.26.27.94 TCP_DENIED/407 1882 PUT http://172.26.27.22:8080/myapp/rest/2/3/29/image2.jpg - NONE/- text/html
1352370671.486 7 172.26.27.94 TCP_MISS/201 282 PUT http://172.26.27.22:8080/myapp/rest/2/3/29/image2.jpg proxyuser DIRECT/172.26.27.22 -
带硬编码报头
Java日志和Squid日志中没有407错误
鱿鱼原木
1352370542.016 8 172.26.27.94 TCP_MISS/201 282 PUT http://172.26.27.22:8080/myapp/rest/2/3/29/image1.jpg proxyuser DIRECT/172.26.27.22 -
1352370542.033 7 172.26.27.94 TCP_MISS/201 282 PUT http://172.26.27.22:8080/myapp/rest/2/3/29/image2.jpg proxyuser DIRECT/172.26.27.22 -
最佳答案：
RFC2616§14.33和第14.34节描述了使用HTTP代理的身份验证过程，与您在HttpClient中看到的完全一样。它包括：
代理发送407（需要代理身份验证）响应，其中包含适用于请求的资源的质询的代理身份验证头，
发出新请求的客户端，其代理授权头由包含身份验证信息的凭据组成。
使用httpclient实现抢占式身份验证在this tutorial中进行了描述（第4.8节），并要求预先填充客户端对象的身份验证缓存。
不幸的是，当预验证到代理服务器时，它们的代码不起作用。理解如何正确使用它可能有点困难，但实际上它就像将参数传递给basicscheme构造函数一样简单：
AuthCache authCache = new BasicAuthCache();
AuthScheme basicAuthScheme = null;
if (isProxy) {
basicAuthScheme = new BasicScheme(ChallengeState.PROXY);
} else {
basicAuthScheme = new BasicScheme(ChallengeState.TARGET);
}
authCache.put(host, basicAuthScheme);
httpContext.setAttribute(ClientContext.AUTH_CACHE, authCache);