Request、Servlet及其子接口

最近看tomcat源码，这类接口多的有点眩，整理出来看一下。（基于tomcat4）

javax.servlet.ServletRequset接口，和org.apache.catalina.Request接口，有什么联系？

其实就是对Request不同层面上的定义。

一、首先看下javax.servlet.Servlet接口

package javax.servlet;

import java.io.IOException;

public abstract interface Servlet {

    public abstract void init(ServletConfig paramServletConfig)

            throws ServletException;

    public abstract ServletConfig getServletConfig();

    public abstract void service(ServletRequest paramServletRequest,

            ServletResponse paramServletResponse) throws ServletException,

            IOException;

    public abstract String getServletInfo();

    public abstract void destroy();

}

这些方法应该非常熟悉了。

二、javax.servlet.http.HttpServlet抽象类

package javax.servlet.http;

public abstract class HttpServlet extends GenericServlet        implements Serializable {

    ...

}

丰富了servlet接口，对应http协议，添加了doGet, doPut, doPost等方法。

三、javax.servlet.ServletRequest接口

package javax.servlet;

public abstract interface ServletRequest {

    public abstract Object getAttribute(String paramString);
public abstract Enumeration getAttributeNames();
public abstract String getCharacterEncoding();
public abstract void setCharacterEncoding(String paramString)

            throws UnsupportedEncodingException;
public abstract int getContentLength();
public abstract String getContentType();
public abstract ServletInputStream getInputStream() throws IOException;
public abstract String getParameter(String paramString);
public abstract Enumeration getParameterNames();
public abstract String[] getParameterValues(String paramString);
public abstract Map getParameterMap();
public abstract String getProtocol();
public abstract String getScheme();
public abstract String getServerName();
public abstract int getServerPort();
public abstract BufferedReader getReader() throws IOException;
public abstract String getRemoteAddr();
public abstract String getRemoteHost();
public abstract void setAttribute(String paramString, Object paramObject);
public abstract void removeAttribute(String paramString);
public abstract Locale getLocale();
public abstract Enumeration getLocales();
public abstract boolean isSecure();
public abstract RequestDispatcher getRequestDispatcher(String paramString);
/** @deprecated */

    public abstract String getRealPath(String paramString);

}

四、javax.servlet.http.HttpServletRequest

public abstract interface HttpServletRequest extends ServletRequest {...}

添加了http协议部分，比如session，cookie等。

五、org.apache.catalina.Requst（tomcat4，后面的版本有变化）

package org.apache.catalina;

public interface Request {
public String getAuthorization();
public void setAuthorization(String authorization);
public Connector getConnector();
public void setConnector(Connector connector);
public Context getContext();
public void setContext(Context context);
public String getInfo();
public ServletRequest getRequest();
public Response getResponse();
public void setResponse(Response response);
public Socket getSocket();
public void setSocket(Socket socket);
public InputStream getStream();
public void setStream(InputStream stream);
public Wrapper getWrapper();
public void setWrapper(Wrapper wrapper);
public ServletInputStream createInputStream() throws IOException;
public void finishRequest() throws IOException;
public Object getNote(String name);
public Iterator getNoteNames();
public void recycle();
public void removeNote(String name);
public void setContentLength(int length);
public void setContentType(String type);
public void setNote(String name, Object value);
public void setProtocol(String protocol);
public void setRemoteAddr(String remote);
public void setScheme(String scheme);
public void setSecure(boolean secure);
public void setServerName(String name);
public void setServerPort(int port);

}

六、org.apache.catalina.HttpRequest

public interface HttpRequest extends Request {...}

增加了对http协议头处理部分，比如url，参数，cookies等。

七、org.apache.catalina.connector.HttpRequestBase

虽然已经弃用了，但可以作为一个参考，实现了jdk和catalina定义的Request

public class HttpRequestBase

    extends RequestBase

    implements HttpRequest, HttpServletRequest {...}

小结

tomcat中，对于jdk中的servlet和ServletRequest肯定要实现的。而tomcat作为容器应用，会有很多自身的需求，所以自己定义了一套接口，跟jdk中不同层面。并且提供两套接口的类，让web开发者使用。

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