關於Tomcat的Pipeline機制

看了tomcat的pipeline和valve的機制。試著寫了乙個簡單的結構，記錄一下。

pipeline--包含了改容器要喚醒的所有任務。每乙個valve表示了乙個特定的任務。容器的pipeline還有乙個basic valve。valve可以自由新增乙個或者多個。

類似於servlet過濾器，乙個pipeline就像乙個過濾鏈，每乙個valve像乙個過濾器。跟過濾器一樣，乙個valve可以操作傳遞給它的request和response方法。讓乙個閥門完成了處理，則進一步處理流水線中的下乙個閥門，基本閥門總是在最後才被呼叫,但是會最先執行裡面的方法。乙個容器可以實現pipeline介面。當容器的invoke方法被呼叫的時候，容器將會處理流水線中的閥門，並乙個接乙個的處理，直到所有的閥門都被處理完畢。

首先，這個是啟動類：

public final class bootstrap5 
catch (exception e) 
}}

headerloggervalve和clientiploggervalve是兩個閥門，用來列印請求頭和使用者ip.

// the servlet instance

private servlet instance = null;

private string servletclass;

private loader loader;

private string name;

private ******pipeline pipeline = new ******pipeline(this);

protected container parent = null;

} @override

public synchronized void addvalve(valve valve)

@override

public servlet allocate() throws servletexception catch (servletexception e) catch (throwable e)

} return instance;

} private servlet loadservlet() throws servletexception

loader loader = getloader();

// acquire an instance of the class loader to be used

if (loader == null)

classloader classloader = loader.getclassloader();

class classclass = null;

try

} catch (classnotfoundexception e)

// instantiate and initialize an instance of the servlet class itself

try catch (throwable e)

// call the initialization method of this servlet

try catch (throwable f)

return servlet;

} @override

public void invoke(request request, response response) throws ioexception,

servletexception

...}這個是誰呢，這個就是下面要說的******pipeline的basic valve,它是用來呼叫真實servlet的service方法的

protected container container;

@override

public void invoke(request request, response response,

valvecontext valvecontext) throws ioexception, servletexception else

} catch (servletexception e)

} @override

public string getinfo()

@override

public container getcontainer()

@override

public void setcontainer(container container)

}

public class ******pipeline implements pipeline 
// the basic valve (if any) associated with this pipeline.
protected valve basic = null;
// the container with which this pipeline is associated.
protected container container = null;
// the array of valves
protected valve valves = new valve[0];
public void setcontainer(container container) 
@override
public valve getbasic() 
@override
public void setbasic(valve valve) 
@override
public void addvalve(valve valve) 
} @override
public valve getvalves() 
@override
public void invoke(request request, response response) throws ioexception,
servletexception 
@override
public void removevalve(valve valve) 
// this class is copied from org.apache.catalina.core.standardpipeline
// class's
// standardpipelinevalvecontext inner class.
protected class ******pipelinevalvecontext implements valvecontext 
@override
public void invokenext(request request, response response)
throws ioexception, servletexception else if ((subscript == valves.length) && (basic != null)) else 
} } // end of inner class
}

下面看下兩個valve類

這樣就實現了pipeline的機制了。

**參考：

how tomcat works

關於Tomcat的Pipeline機制

Linux關於tomcat的命令

關於配置Tomcat的URIEncoding

關於配置Tomcat的URIEncoding

關於Tomcat的Pipeline機制

Linux關於tomcat的命令

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關於配置Tomcat的URIEncoding

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