servlet容器启动过程

 

 

 

Web应用的初始化工作

创建Servlet实例

在Servlet的解析工作中，Servlet被包装成StandarWrapper添加在Context容器中。

 

servlet 体系结构

servlet interface:

package javax.servlet;import java.io.IOException;public interface Servlet {    void init(ServletConfig var1) throws ServletException;    ServletConfig getServletConfig();    void service(ServletRequest var1, ServletResponse var2) throws ServletException, IOException;    String getServletInfo();    void destroy();}

servletConfig interface:

package javax.servlet;import java.util.Enumeration;public interface ServletConfig {    String getServletName();    ServletContext getServletContext();    String getInitParameter(String var1);    Enumeration getInitParameterNames();}

servletContext interface:

package javax.servlet;import java.io.InputStream;import java.net.MalformedURLException;import java.net.URL;import java.util.Enumeration;import java.util.Set;public interface ServletContext {    String getContextPath();    ServletContext getContext(String var1);    int getMajorVersion();    int getMinorVersion();    String getMimeType(String var1);    Set getResourcePaths(String var1);    URL getResource(String var1) throws MalformedURLException;    InputStream getResourceAsStream(String var1);    RequestDispatcher getRequestDispatcher(String var1);    RequestDispatcher getNamedDispatcher(String var1);    /** @deprecated */    Servlet getServlet(String var1) throws ServletException;    /** @deprecated */    Enumeration getServlets();    /** @deprecated */    Enumeration getServletNames();    void log(String var1);    /** @deprecated */    void log(Exception var1, String var2);    void log(String var1, Throwable var2);    String getRealPath(String var1);    String getServerInfo();    String getInitParameter(String var1);    Enumeration getInitParameterNames();    Object getAttribute(String var1);    Enumeration getAttributeNames();    void setAttribute(String var1, Object var2);    void removeAttribute(String var1);    String getServletContextName();}

servletRequest interface:

package javax.servlet;import java.io.BufferedReader;import java.io.IOException;import java.io.UnsupportedEncodingException;import java.util.Enumeration;import java.util.Locale;import java.util.Map;public interface ServletRequest {    Object getAttribute(String var1);    Enumeration getAttributeNames();    String getCharacterEncoding();    void setCharacterEncoding(String var1) throws UnsupportedEncodingException;    int getContentLength();    String getContentType();    ServletInputStream getInputStream() throws IOException;    String getParameter(String var1);    Enumeration getParameterNames();    String[] getParameterValues(String var1);    Map getParameterMap();    String getProtocol();    String getScheme();    String getServerName();    int getServerPort();    BufferedReader getReader() throws IOException;    String getRemoteAddr();    String getRemoteHost();    void setAttribute(String var1, Object var2);    void removeAttribute(String var1);    Locale getLocale();    Enumeration getLocales();    boolean isSecure();    RequestDispatcher getRequestDispatcher(String var1);    /** @deprecated */    String getRealPath(String var1);    int getRemotePort();    String getLocalName();    String getLocalAddr();    int getLocalPort();}

servletResponse interface:

package javax.servlet;import java.io.BufferedReader;import java.io.IOException;import java.io.UnsupportedEncodingException;import java.util.Enumeration;import java.util.Locale;import java.util.Map;public interface ServletRequest {    Object getAttribute(String var1);    Enumeration getAttributeNames();    String getCharacterEncoding();    void setCharacterEncoding(String var1) throws UnsupportedEncodingException;    int getContentLength();    String getContentType();    ServletInputStream getInputStream() throws IOException;    String getParameter(String var1);    Enumeration getParameterNames();    String[] getParameterValues(String var1);    Map getParameterMap();    String getProtocol();    String getScheme();    String getServerName();    int getServerPort();    BufferedReader getReader() throws IOException;    String getRemoteAddr();    String getRemoteHost();    void setAttribute(String var1, Object var2);    void removeAttribute(String var1);    Locale getLocale();    Enumeration getLocales();    boolean isSecure();    RequestDispatcher getRequestDispatcher(String var1);    /** @deprecated */    String getRealPath(String var1);    int getRemotePort();    String getLocalName();    String getLocalAddr();    int getLocalPort();}

ServletConfig在Servlet init时由容器传过来。

Servlet如何工作

服务器如何根据URL到达正确地Servlet容器中的。

Servlet中的Listener

Filter如何工作

filter interface:

package javax.servlet;import java.io.IOException;public interface Filter {    void init(FilterConfig var1) throws ServletException;    void doFilter(ServletRequest var1, ServletResponse var2, FilterChain var3) throws IOException, ServletException;    void destroy();}

filterConfig interface:

package javax.servlet;import java.util.Enumeration;public interface FilterConfig {    String getFilterName();    ServletContext getServletContext();    String getInitParameter(String var1);    Enumeration
      
        getInitParameterNames();}
      

filterChain interface:

package javax.servlet;import java.io.IOException;public interface FilterChain {    void doFilter(ServletRequest var1, ServletResponse var2) throws IOException, ServletException;}