16、Tomcat 源码解析 - Tomcat Connector
这篇分析Connector组件，之前第八篇分析StandardService中涉及到Connector，
分析Service的时候，知道StartInternal里面会调用connectors的每个connector的start方法，一个service可以有多个connector，可以从catalina类的digester里面可以看到addConnector的地方，下面是代码片段：
protected Digester createStartDigester() {
digester.addRule("Server/Service/Connector",
new ConnectorCreateRule());
digester.addRule("Server/Service/Connector", new SetAllPropertiesRule(
new String[]{"executor", "sslImplementationName", "protocol"}));
digester.addSetNext("Server/Service/Connector",
"addConnector",
"org.apache.catalina.connector.Connector");
}
前面分析Service的Digester的时候，知道ConnectorCreateRule规则，解析到Connector标签的时候，读取Connector的executor标签属性，从service中获得Executor，读取Connector的protocol标签属性，protocol作为构造方法参数创建Connector，给connector的protocol设置executor，这里也是可以调优的地方。
前面分析rule的时候知道，SetNextRule会调用digester的service. addConnector,下面是StandardService.addConnector代码片段
public void addConnector(Connector connector) {
synchronized (connectorsLock) {
connector.setService(this);
Connector results[] = new Connector[connectors.length + 1];
System.arraycopy(connectors, 0, results, 0, connectors.length);
results[connectors.length] = connector;
connectors = results;
if (getState().isAvailable()) {
try {
connector.start();
} catch (LifecycleException e) {
log.error(sm.getString(
"standardService.connector.startFailed",
connector), e);
}
}
// Report this property change to interested listeners
support.firePropertyChange("connector", null, connector);
}
}
下面分析创建Connector对象链的，跟之前一样，看Catalian的createStartDigester里面关于Connector的rule配置片段
protected Digester createStartDigester() {
……………………..
//解析到Connector标签的时候，读取Connector的executor标签属性，从service
中获得Executor，读取Connector的protocol标签属性，protocol作为构造方法参数创建Connector，给connector的protocol设置executor，这里也是可以调优的地方
digester.addRule("Server/Service/Connector",
new ConnectorCreateRule());
//设置Connector标签的属性给Connector对象，除了executor、sslImplementationName和protocol
digester.addRule("Server/Service/Connector", new SetAllPropertiesRule(
new String[]{"executor", "sslImplementationName", "protocol"}));
//调用service的addConnector传入上面rule创建的Connector
digester.addSetNext("Server/Service/Connector",
"addConnector",
"org.apache.catalina.connector.Connector");
//解析到xx/xx/ Connector/SSLHostConfig标签的时候，创建对象SSLHostConfig，push进digester
digester.addObjectCreate("Server/Service/Connector/SSLHostConfig",
"org.apache.tomcat.util.net.SSLHostConfig");
//解析到xx/xx/ Connector/SSLHostConfig标签的时候，设置标签的属性给ObjectCreateRule创建的SSLHostConfig
digester.addSetProperties("Server/Service/Connector/SSLHostConfig");
//同上解析到SSLHostConfig的时候，调用Connector的方法addSslHostConfig，传入SSLHostConfig
digester.addSetNext("Server/Service/Connector/SSLHostConfig",
"addSslHostConfig",
"org.apache.tomcat.util.net.SSLHostConfig");
//解析到xx/xx/ Connector/SSLHostConfig/ Certificate标签的时候，执行CertificateCreateRule，CertificateCreateRule规则是读取Certificate标签的type属性，new SSLHostConfigCertificate(sslHostConfig, type)，push进digester
digester.addRule("Server/Service/Connector/SSLHostConfig/Certificate",
new CertificateCreateRule());
//同上，设置Certificate标签属性给对象SSLHostConfigCertificate，除了type属性
digester.addRule("Server/Service/Connector/SSLHostConfig/Certificate",
new SetAllPropertiesRule(new String[]{"type"}));
//同上，解析到Certificate标签的，调用SSLHostConfig的addCertificate方法，传入SSLHostConfigCertificate
digester.addSetNext("Server/Service/Connector/SSLHostConfig/Certificate",
"addCertificate",
"org.apache.tomcat.util.net.SSLHostConfigCertificate");
//解析到xx/xx/ Connector/Listener的时候，创建Listener，className属性必须指定
digester.addObjectCreate("Server/Service/Connector/Listener",
null, // MUST be specified in the element
"className");
//同上，解析Listener标签的时候，设置Listener标签属性给创建的Listener对象
digester.addSetProperties("Server/Service/Connector/Listener");
//同上，解析Listener标签的时候，调用Connector的addLifecycleListener方法，传入ObjectCreateRule 创建的对象
digester.addSetNext("Server/Service/Connector/Listener",
"addLifecycleListener",
"org.apache.catalina.LifecycleListener");
//解析到xx/xx/ Connector/UpgradeProtocol，创建className指定的对象，className必须指定
digester.addObjectCreate("Server/Service/Connector/UpgradeProtocol",
null, // MUST be specified in the element
"className");
//同上，解析到UpgradeProtocol标签的时候，设置UpgradeProtocol标签属性给上面rule创建的对象
digester.addSetProperties("Server/Service/Connector/ UpgradeProtocol ");
//同上，解析到UpgradeProtocol标签的时候，调用Connector的addUpgradeProtocol，传入上面rule创建的对象
digester.addSetNext("Server/Service/Connector/UpgradeProtocol",
"addUpgradeProtocol",
"org.apache.coyote.UpgradeProtocol");
………………………
}
现在看下Connector类，public class Connector extends LifecycleMBeanBase这是Connector类的签名，可以看出他也是LifeCycle继承链下的组件，这个主要是看Internal系列的方法，先看下类的构造方法
public Connector() {
//默认是org.apache.coyote.http11.Http11NioProtocol
this("org.apache.coyote.http11.Http11NioProtocol");
}
public Connector(String protocol) {
boolean aprConnector = AprLifecycleListener.isAprAvailable() &&
AprLifecycleListener.getUseAprConnector();
// ConnectorCreateRule解析，调用构造方法，传入Connector的protocol标签属性值
if ("HTTP/1.1".equals(protocol) || protocol == null) {
if (aprConnector) {
protocolHandlerClassName = "org.apache.coyote.http11.Http11AprProtocol";
} else {
protocolHandlerClassName = "org.apache.coyote.http11.Http11NioProtocol";
}
} else if ("AJP/1.3".equals(protocol)) {
if (aprConnector) {
protocolHandlerClassName = "org.apache.coyote.ajp.AjpAprProtocol";
} else {
protocolHandlerClassName = "org.apache.coyote.ajp.AjpNioProtocol";
}
} else {
protocolHandlerClassName = protocol;
}
ProtocolHandler p = null;
try {
//反射实例化ProtocolHandler之前指定的protocolHandlerClassName，ProtocolHandler实例
Class<?> clazz = Class.forName(protocolHandlerClassName);
p = (ProtocolHandler) clazz.newInstance();
} catch (Exception e) {
log.error(sm.getString(
"coyoteConnector.protocolHandlerInstantiationFailed"), e);
} finally {
this.protocolHandler = p;
}
…………………….
}
現在看下Internal方法，initInternal、startInternal、stopInternal和destroyInternal方法
initInternal 方法
protected void initInternal() throws LifecycleException {
super.initInternal();
if (protocolHandler == null) {
throw new LifecycleException(
sm.getString("coyoteConnector.protocolHandlerInstantiationFailed"));
}
// 实例化CoyoteAdapter对象，当前Connector作为参数，CoyoteAdapter这个类很重要，后面单独篇分析
adapter = new CoyoteAdapter(this);
//设置Adapter给protocolHandler
protocolHandler.setAdapter(adapter);
if (null == parseBodyMethodsSet) {
setParseBodyMethods(getParseBodyMethods());
}
//如果protocolHandler要求Apr但是Apr不可用话报错
if(protocolHandler.isAprRequired() && !AprLifecycleListener.isAprAvailable()) {
throw new LifecycleException(sm.getString("coyoteConnector.protocolHandlerNoApr",
getProtocolHandlerClassName()));
}
//如果Apr可以用并且getUseOpenSSL为true并且protocolHandler是AbstractHttp11JsseProtocol，设置handler的SslImplementationName，参数是OpenSSLImplementation类名
if (AprLifecycleListener.isAprAvailable() && AprLifecycleListener.getUseOpenSSL() &&
protocolHandler instanceof AbstractHttp11JsseProtocol) {
AbstractHttp11JsseProtocol<?> jsseProtocolHandler =
(AbstractHttp11JsseProtocol<?>) protocolHandler;
if (jsseProtocolHandler.isSSLEnabled() &&
jsseProtocolHandler.getSslImplementationName() == null) {
// OpenSSL is compatible with the JSSE configuration, so use it if APR is available
jsseProtocolHandler.setSslImplementationName(OpenSSLImplementation.class.getName());
}
}
try {
//调用handler的init
protocolHandler.init();
} catch (Exception e) {
throw new LifecycleException(
sm.getString("coyoteConnector.protocolHandlerInitializationFailed"), e);
}
}
其中startInternal、stopInternal和destroyInternal 方法就是protocolHandler对象对应的start、stop和destroy方法的调用
上面CoyoteAdapter类和handler与Connector的对象关系如下图
