Request的生命歷程，可以參見常量類org.apache.coyote.Constants.java
// Request states
public static final int STAGE_NEW = 0;
public static final int STAGE_PARSE = 1;
public static final int STAGE_PREPARE = 2;
public static final int STAGE_SERVICE = 3;
public static final int STAGE_ENDINPUT = 4;
public static final int STAGE_ENDOUTPUT = 5;
public static final int STAGE_KEEPALIVE = 6;
public static final int STAGE_ENDED = 7;
和用到這些常量的地方 Http11Processor.java (代碼貼的比較多，可以用瀏覽器的 查找功能來查找上面的常量)
while (started && !error && keepAlive && !endpoint.isPaused()) {
// Parsing the request header
try {
if (keptAlive) {
if (keepAliveTimeout > 0) {
socket.setSoTimeout(keepAliveTimeout);
}
else if (soTimeout > 0) {
socket.setSoTimeout(soTimeout);
}
}
inputBuffer.parseRequestLine();
request.setStartTime(System.currentTimeMillis());
keptAlive = true;
if (disableUploadTimeout) {
socket.setSoTimeout(soTimeout);
} else {
socket.setSoTimeout(timeout);
}
inputBuffer.parseHeaders();
} catch (IOException e) {
error = true;
break;
} catch (Throwable t) {
if (log.isDebugEnabled()) {
log.debug(sm.getString("http11processor.header.parse"), t);
}
// 400 - Bad Request
response.setStatus(400);
adapter.log(request, response, 0);
error = true;
}
if (!error) {
// Setting up filters, and parse some request headers
rp.setStage(org.apache.coyote.Constants.STAGE_PREPARE);
try {
prepareRequest();
} catch (Throwable t) {
if (log.isDebugEnabled()) {
log.debug(sm.getString("http11processor.request.prepare"), t);
}
// 400 - Internal Server Error
response.setStatus(400);
adapter.log(request, response, 0);
error = true;
}
}
if (maxKeepAliveRequests > 0 && --keepAliveLeft == 0)
keepAlive = false;
// Process the request in the adapter
if (!error) {
try {
rp.setStage(org.apache.coyote.Constants.STAGE_SERVICE);
adapter.service(request, response);
// Handle when the response was committed before a serious
// error occurred. Throwing a ServletException should both
// set the status to 500 and set the errorException.
// If we fail here, then the response is likely already
// committed, so we can't try and set headers.
if(keepAlive && !error) { // Avoid checking twice.
error = response.getErrorException() != null ||
statusDropsConnection(response.getStatus());
}
} catch (InterruptedIOException e) {
error = true;
} catch (Throwable t) {
log.error(sm.getString("http11processor.request.process"), t);
// 500 - Internal Server Error
response.setStatus(500);
adapter.log(request, response, 0);
error = true;
}
}
// Finish the handling of the request
try {
rp.setStage(org.apache.coyote.Constants.STAGE_ENDINPUT);
// If we know we are closing the connection, don't drain input.
// This way uploading a 100GB file doesn't tie up the thread
// if the servlet has rejected it.
if(error)
inputBuffer.setSwallowInput(false);
inputBuffer.endRequest();
} catch (IOException e) {
error = true;
} catch (Throwable t) {
log.error(sm.getString("http11processor.request.finish"), t);
// 500 - Internal Server Error
response.setStatus(500);
adapter.log(request, response, 0);
error = true;
}
try {
rp.setStage(org.apache.coyote.Constants.STAGE_ENDOUTPUT);
outputBuffer.endRequest();
} catch (IOException e) {
error = true;
} catch (Throwable t) {
log.error(sm.getString("http11processor.response.finish"), t);
error = true;
}
// If there was an error, make sure the request is counted as
// and error, and update the statistics counter
if (error) {
response.setStatus(500);
}
request.updateCounters();
rp.setStage(org.apache.coyote.Constants.STAGE_KEEPALIVE);
// Don't reset the param - we'll see it as ended. Next request
// will reset it
// thrA.setParam(null);
// Next request
inputBuffer.nextRequest();
outputBuffer.nextRequest();
}
rp.setStage(org.apache.coyote.Constants.STAGE_ENDED);
// Recycle
inputBuffer.recycle();
outputBuffer.recycle();
this.socket = null;
// Recycle ssl info
sslSupport = null;
}
Connector配置解析：
官方文檔：
http://tomcat.apache.org/tomcat-6.0-doc/config/http.html
文檔中講了比較多的選項的用法，其中，我把比較重要的幾個列舉下：
maxKeepAliveRequests
在服務器關閉socket連接之前，能保持的最大請求數。
maxThreads
服務器的最大線程數。講白了就是Worker的最大數目，當然如果配置開啓了Executor的話，這個配置項便是沒有用的。
這裏你會不會有疑問，線程數和請求數有什麼關係。根據我上一篇文章tomcat分配請求 的分析，一個Worker線程對應一個請求。
那麼你會不會有更多的疑問，maxThreads如何設置得比 maxKeepAliveRequests 小會怎麼辦？
請看下面這段代碼
Http11Processor.java
int keepAliveLeft = maxKeepAliveRequests;
int soTimeout = endpoint.getSoTimeout();
// When using an executor, these values may return non-positive values
int curThreads = endpoint.getCurrentThreadsBusy();
int maxThreads = endpoint.getMaxThreads();
if (curThreads > 0 && maxThreads > 0) {
// Only auto-disable keep-alive if the current thread usage % can be
// calculated correctly
if ((curThreads*100)/maxThreads > 75) {
keepAliveLeft = 1; // 當前使用線程是最大線程數的75%的時候，會自動禁用keepAlive
}
}
while (started && !error && keepAlive) {
……
if (maxKeepAliveRequests > 0 && --keepAliveLeft == 0)
keepAlive = false;
……
}
當前使用線程是最大線程的75% 的時候，會自動禁用keepAlive
所以maxThreads設置得比maxKeepAliveRequests 小，則這個maxKeepAliveRequests 設置時沒有效果的。
當maxThreads設置肯定要比 maxKeepAliveRequests 來的大，而且 maxKeepAliveRequests 不會超過maxThreads的75%！！
默認：maxThreads 爲 200
maxKeepAliveRequests 爲100
keepAliveTimeout
服務器Socket讀取HTTP請求行到來的限制時間。 以millionseconds爲單位。默認和connectionTimeout 的值一樣。
connectionTimeout
單位是毫秒，Connector從接受連接到提交URI請求數據的等待的時間。
開始這個我沒搞懂，不過找到了這篇文章： http://twotwoandapple.blogbus.com/logs/62770043.html 上面的解釋和測試。
也可以看下面的代碼：Http11Processor.java
while (started && !error && keepAlive) {
// Parsing the request header
try {
if (keptAlive) {
if (keepAliveTimeout > 0) {
socket.setSoTimeout(keepAliveTimeout);
}
else if (soTimeout > 0) {
socket.setSoTimeout(soTimeout);
}
}
// 服務器獲取客戶端請求行,這裏會調用inputBuffer的read 方法，引起socket阻塞，阻塞時間超過soTimeout的話就會SocketTimeOutException
inputBuffer.parseRequestLine();
disableUploadTimeout
是否允許在上傳操作的時候給與更長的socketTimeOut時間。默認false不允許。
如果設置爲true，則默認爲5分鐘限制，超過5分鐘則會報SocketTimeOut異常。
如果要改這個時間，需要用這個Attribute： timeout 這個官方文檔沒有寫，不知道爲什麼，可能不建議修改吧，因爲5分鐘是和apache 的httpd的時間保持一致的。
類似：
<Connector port="8080" protocol="HTTP/1.1"
connectionTimeout="20000"
redirectPort="8443" disableUploadTimeout="false" timeout="600000"/>
其中HTTP 協議，最好參考下RFC的文檔 結合Http11Protocal 和 Http11Processor來看比較好