javaee-servlet类源代码
贴贴源代码，心理就好受多了，哎，犯贱吗！
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ServletAPI?2.5的源代码
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1.ServletContext就是我们经常说的application，不管是否常用，但总之是如雷贯耳。
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package javax.servlet;import java.io.InputStream;import java.net.MalformedURLException;import java.net.URL;import java.util.Enumeration;import java.util.Set;public abstract interface ServletContext{ public abstract String getContextPath(); public abstract ServletContext getContext(String paramString); public abstract int getMajorVersion(); public abstract int getMinorVersion(); public abstract String getMimeType(String paramString); public abstract Set getResourcePaths(String paramString); public abstract URL getResource(String paramString) throws MalformedURLException; public abstract InputStream getResourceAsStream(String paramString); public abstract RequestDispatcher getRequestDispatcher(String paramString); public abstract RequestDispatcher getNamedDispatcher(String paramString); /** * @deprecated */ public abstract Servlet getServlet(String paramString) throws javax.servlet.ServletException; /** * @deprecated */ public abstract Enumeration getServlets(); /** * @deprecated */ public abstract Enumeration getServletNames(); public abstract void log(String paramString); /** * @deprecated */ public abstract void log(Exception paramException, String paramString); public abstract void log(String paramString, Throwable paramThrowable); public abstract String getRealPath(String paramString); public abstract String getServerInfo(); public abstract String getInitParameter(String paramString); public abstract Enumeration getInitParameterNames(); public abstract Object getAttribute(String paramString); public abstract Enumeration getAttributeNames(); public abstract void setAttribute(String paramString, Object paramObject); public abstract void removeAttribute(String paramString); public abstract String getServletContextName();}??
2.接着是ServletConfig，用的真不多，就是从web.xml文件中提取参数。
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? ?web.xml
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<!-- begin --><servlet><servlet-name>ConfigTestServlet</servlet-name><servlet-class>org.it315.ConfigTestServlet</servlet-class><init-param><param-name>firstname</param-name><param-value>zhangsan-张三</param-value></init-param><init-param><param-name>lastname</param-name><param-value>lisi-李四</param-value></init-param></servlet><servlet-mapping><servlet-name>ConfigTestServlet</servlet-name><url-pattern>/configTest</url-pattern></servlet-mapping><!--end -->?
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? ?ServletConfig源代码
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package javax.servlet;import java.util.Enumeration;public abstract interface ServletConfig{ public abstract String getServletName(); public abstract ServletContext getServletContext(); public abstract String getInitParameter(String paramString); public abstract Enumeration getInitParameterNames();}?
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3.下面是Servlet的源代码（直接反编译来的，省的下载了），不管你知道不知道，你确一直在用
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? ?只有在首次访问时，容器发现内存中没有当前servlet，才创建servlet对象。
单例吗？
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? 下面的init方法，在Servlet的整个生命周期内只被调用一次。
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package javax.servlet;import java.io.IOException;public abstract interface Servlet{ public abstract void init(ServletConfig paramServletConfig) throws javax.servlet.ServletException; public abstract ServletConfig getServletConfig(); public abstract void service(ServletRequest paramServletRequest, ServletResponse paramServletResponse) throws javax.servlet.ServletException, IOException; public abstract String getServletInfo(); public abstract void destroy();}??
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4.GenericServlet实现了Servlet, ServletConfig接口（Generic为通用之意）。同上，不管你知道不知道，你确一直在用
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package javax.servlet;import java.io.IOException;import java.io.Serializable;import java.util.Enumeration;import java.util.ResourceBundle;public abstract class GenericServlet implements Servlet, ServletConfig, Serializable{ private static final String LSTRING_FILE = "javax.servlet.LocalStrings"; private static ResourceBundle lStrings = ResourceBundle.getBundle("javax.servlet.LocalStrings"); private transient ServletConfig config; public void destroy() { } public String getInitParameter(String name) { ServletConfig sc = getServletConfig(); if (sc == null) { throw new IllegalStateException(lStrings.getString("err.servlet_config_not_initialized")); } return sc.getInitParameter(name); } public Enumeration getInitParameterNames() { ServletConfig sc = getServletConfig(); if (sc == null) { throw new IllegalStateException(lStrings.getString("err.servlet_config_not_initialized")); } return sc.getInitParameterNames(); } public ServletConfig getServletConfig() { return this.config; } public ServletContext getServletContext() { ServletConfig sc = getServletConfig(); if (sc == null) { throw new IllegalStateException(lStrings.getString("err.servlet_config_not_initialized")); } return sc.getServletContext(); } public String getServletInfo() { return ""; } public void init(ServletConfig config) throws javax.servlet.ServletException { this.config = config; init(); } public void init() throws javax.servlet.ServletException { } public void log(String msg) { getServletContext().log(getServletName() + ": " + msg); } public void log(String message, Throwable t) { getServletContext().log(getServletName() + ": " + message, t); } public abstract void service(ServletRequest paramServletRequest, ServletResponse paramServletResponse) throws javax.servlet.ServletException, IOException; public String getServletName() { ServletConfig sc = getServletConfig(); if (sc == null) { throw new IllegalStateException(lStrings.getString("err.servlet_config_not_initialized")); } return sc.getServletName(); }}?
5.HttpServlet，到这，知道人就多了，呵呵 。但除了doGet，doPost，service，其他从未用过。
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package javax.servlet.http;import java.io.IOException;import java.io.Serializable;import java.lang.reflect.Method;import java.text.MessageFormat;import java.util.Enumeration;import java.util.ResourceBundle;import javax.servlet.GenericServlet;import javax.servlet.ServletException;import javax.servlet.ServletOutputStream;import javax.servlet.ServletRequest;import javax.servlet.ServletResponse;public abstract class HttpServlet extends GenericServlet implements Serializable{ private static final String METHOD_DELETE = "DELETE"; private static final String METHOD_HEAD = "HEAD"; private static final String METHOD_GET = "GET"; private static final String METHOD_OPTIONS = "OPTIONS"; private static final String METHOD_POST = "POST"; private static final String METHOD_PUT = "PUT"; private static final String METHOD_TRACE = "TRACE"; private static final String HEADER_IFMODSINCE = "If-Modified-Since"; private static final String HEADER_LASTMOD = "Last-Modified"; private static final String LSTRING_FILE = "javax.servlet.http.LocalStrings"; private static ResourceBundle lStrings = ResourceBundle.getBundle("javax.servlet.http.LocalStrings"); protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { String protocol = req.getProtocol(); String msg = lStrings.getString("http.method_get_not_supported"); if (protocol.endsWith("1.1")) resp.sendError(405, msg); else resp.sendError(400, msg); } protected long getLastModified(HttpServletRequest req) { return -1L; } protected void doHead(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { NoBodyResponse response = new NoBodyResponse(resp); doGet(req, response); response.setContentLength(); } protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { String protocol = req.getProtocol(); String msg = lStrings.getString("http.method_post_not_supported"); if (protocol.endsWith("1.1")) resp.sendError(405, msg); else resp.sendError(400, msg); } protected void doPut(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { String protocol = req.getProtocol(); String msg = lStrings.getString("http.method_put_not_supported"); if (protocol.endsWith("1.1")) resp.sendError(405, msg); else resp.sendError(400, msg); } protected void doDelete(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { String protocol = req.getProtocol(); String msg = lStrings.getString("http.method_delete_not_supported"); if (protocol.endsWith("1.1")) resp.sendError(405, msg); else resp.sendError(400, msg); } private Method[] getAllDeclaredMethods(Class c) { if (c.equals(HttpServlet.class)) { return null; } Method[] parentMethods = getAllDeclaredMethods(c.getSuperclass()); Method[] thisMethods = c.getDeclaredMethods(); if ((parentMethods != null) && (parentMethods.length > 0)) { Method[] allMethods = new Method[parentMethods.length + thisMethods.length]; System.arraycopy(parentMethods, 0, allMethods, 0, parentMethods.length); System.arraycopy(thisMethods, 0, allMethods, parentMethods.length, thisMethods.length); thisMethods = allMethods; } return thisMethods; } protected void doOptions(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { Method[] methods = getAllDeclaredMethods(getClass()); boolean ALLOW_GET = false; boolean ALLOW_HEAD = false; boolean ALLOW_POST = false; boolean ALLOW_PUT = false; boolean ALLOW_DELETE = false; boolean ALLOW_TRACE = true; boolean ALLOW_OPTIONS = true; for (int i = 0; i < methods.length; ++i) { Method m = methods[i]; if (m.getName().equals("doGet")) { ALLOW_GET = true; ALLOW_HEAD = true; } if (m.getName().equals("doPost")) ALLOW_POST = true; if (m.getName().equals("doPut")) ALLOW_PUT = true; if (m.getName().equals("doDelete")) ALLOW_DELETE = true; } String allow = null; if ((ALLOW_GET) && (allow == null)) allow = "GET"; if (ALLOW_HEAD) if (allow == null) allow = "HEAD"; else allow = allow + ", HEAD"; if (ALLOW_POST) if (allow == null) allow = "POST"; else allow = allow + ", POST"; if (ALLOW_PUT) if (allow == null) allow = "PUT"; else allow = allow + ", PUT"; if (ALLOW_DELETE) if (allow == null) allow = "DELETE"; else allow = allow + ", DELETE"; if (ALLOW_TRACE) if (allow == null) allow = "TRACE"; else allow = allow + ", TRACE"; if (ALLOW_OPTIONS) if (allow == null) allow = "OPTIONS"; else allow = allow + ", OPTIONS"; resp.setHeader("Allow", allow); } protected void doTrace(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { String CRLF = "\r\n"; String responseString = "TRACE " + req.getRequestURI() + " " + req.getProtocol(); Enumeration reqHeaderEnum = req.getHeaderNames(); while (reqHeaderEnum.hasMoreElements()) { String headerName = (String)reqHeaderEnum.nextElement(); responseString = responseString + CRLF + headerName + ": " + req.getHeader(headerName); } responseString = responseString + CRLF; int responseLength = responseString.length(); resp.setContentType("message/http"); resp.setContentLength(responseLength); ServletOutputStream out = resp.getOutputStream(); out.print(responseString); out.close(); } protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { long lastModified; String method = req.getMethod(); if (method.equals("GET")) { lastModified = getLastModified(req); if (lastModified == -1L) { doGet(req, resp); } else { long ifModifiedSince = req.getDateHeader("If-Modified-Since"); if (ifModifiedSince < lastModified / 1000L * 1000L) { maybeSetLastModified(resp, lastModified); doGet(req, resp); } else { resp.setStatus(304); } } } else if (method.equals("HEAD")) { lastModified = getLastModified(req); maybeSetLastModified(resp, lastModified); doHead(req, resp); } else if (method.equals("POST")) { doPost(req, resp); } else if (method.equals("PUT")) { doPut(req, resp); } else if (method.equals("DELETE")) { doDelete(req, resp); } else if (method.equals("OPTIONS")) { doOptions(req, resp); } else if (method.equals("TRACE")) { doTrace(req, resp); } else { String errMsg = lStrings.getString("http.method_not_implemented"); Object[] errArgs = new Object[1]; errArgs[0] = method; errMsg = MessageFormat.format(errMsg, errArgs); resp.sendError(501, errMsg); } } private void maybeSetLastModified(HttpServletResponse resp, long lastModified) { if (resp.containsHeader("Last-Modified")) return; if (lastModified >= -3069086688014761984L) resp.setDateHeader("Last-Modified", lastModified); } public void service(ServletRequest req, ServletResponse res) throws ServletException, IOException { HttpServletRequest request; HttpServletResponse response; try { request = (HttpServletRequest)req; response = (HttpServletResponse)res; } catch (ClassCastException e) { throw new ServletException("non-HTTP request or response"); } service(request, response); }}?…………