HttpSolrCall是solr底层发送http请求的中转站，首先看一下它的构造函数
public HttpSolrCall(SolrDispatchFilter solrDispatchFilter, CoreContainer cores,
HttpServletRequest request, HttpServletResponse response, boolean retry) {
this.solrDispatchFilter = solrDispatchFilter;
this.cores = cores;
this.req = request;
this.response = response;
this.retry = retry;
this.requestType = RequestType.UNKNOWN;
queryParams = SolrRequestParsers.parseQueryString(req.getQueryString());
}
没有什么特别之处，主要是进行了一些赋值操作
接下来这个类里面有个 private void init() throws Exception {}方法
主要是解析req从中获取core名称，并向req中写入一些属性，初始化一些core相关的参数，检查core在不在corecontainer中，并做一些错误异常抛出的处理，以及得到当前url的action类型。在这个方法里还调用了一个方法
extractHandlerFromURLPath(SolrRequestParsers parser) throws Exception {}
此方法从url中解析出当前请求需要用到的SolrRequestHandler，这个SolrRequestHandler在solr中很重要，每一种不同的request请求都对应着一个SolrRequestHandler，在后面的文章中我们将详细介绍
solrReq = parser.parse(core, path, req);
invalidStates = checkStateIsValid(solrReq.getParams().get(CloudSolrClient.STATE_VERSION));
String qt = solrReq.getParams().get(CommonParams.QT);
handler = core.getRequestHandler(qt);
下面这个方法是这个类的核心
public Action call() throws IOException {
switch (action) {
case ADMIN:
handleAdminRequest();
return RETURN;
case REMOTEQUERY:
remoteQuery(coreUrl + path, resp);
return RETURN;
case PROCESS:
final Method reqMethod = Method.getMethod(req.getMethod());
HttpCacheHeaderUtil.setCacheControlHeader(config, resp, reqMethod);
// unless we have been explicitly told not to, do cache validation
// if we fail cache validation, execute the query
if (config.getHttpCachingConfig().isNever304() ||
!HttpCacheHeaderUtil.doCacheHeaderValidation(solrReq, req, reqMethod, resp)) {
SolrQueryResponse solrRsp = new SolrQueryResponse();
/* even for HEAD requests, we need to execute the handler to
* ensure we don't get an error (and to make sure the correct
* QueryResponseWriter is selected and we get the correct
* Content-Type)
*/
SolrRequestInfo.setRequestInfo(new SolrRequestInfo(solrReq, solrRsp));
execute(solrRsp);
HttpCacheHeaderUtil.checkHttpCachingVeto(solrRsp, resp, reqMethod);
Iterator<Map.Entry<String, String>> headers = solrRsp.httpHeaders();
while (headers.hasNext()) {
Map.Entry<String, String> entry = headers.next();
resp.addHeader(entry.getKey(), entry.getValue());
}
QueryResponseWriter responseWriter = core.getQueryResponseWriter(solrReq);
if (invalidStates != null) solrReq.getContext().put(CloudSolrClient.STATE_VERSION, invalidStates);
writeResponse(solrRsp, responseWriter, reqMethod);
}
return RETURN;
default: return action;
}
}
在这些代码里处理了ADMIN，REMOTEQUERY，PROCESS三种类型的请求，其他类型的action不做操作
ADMIN的请求在本机
这个类的分析到此结束，下一篇文章我们将分析CoreContainer这个类的作用