(3):スプリングの動き方について
緒論
コメントリンクを見て個人ブログで整理した内容です.
サーブレットコンテナは、開発者がWebサーバと通信するためにDispatcher Sevletを作成したり、ソケットを作成したり、特定のポートに転送したり、ストリームを生成したりする複雑なタスクに代わることができます.コンテナは、サーブレットの作成から破棄までの一連のサイクルを管理します.サーブレットコンテナは、要求を受信すると新しいJavaスレッドを生成します.私たちが知っている平板コンテナはTomcatを表しています.
サーブレットとは?
サーブレット動作手順
テンプレートサイクルの作成
いわゆるサーブレット容器
テンプレート実行順序
次はSubetの実施形態です
package javax.servlet.http; import java.io.IOException; import java.io.OutputStreamWriter; import java.io.PrintWriter; import java.io.UnsupportedEncodingException; import java.lang.reflect.Method; import java.text.MessageFormat; import java.util.Enumeration; import java.util.Locale; 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 java.io.Sericalizable { 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(LSTRING_FILE); public HttpServlet() { } 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(HttpServletResponse.SC_METHOD_NOT_ALLOWED, msg); } else { resp.sendError(HttpServletResponse.SC_BAD_REQUEST, msg); } } protected long getLastModified(HttpServletRequest req) { return -1; } 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(HttpServletResponse.SC_METHOD_NOT_ALLOWED, msg); } else { resp.sendError(HttpServletResponse.SC_BAD_REQUEST, 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(HttpServletResponse.SC_METHOD_NOT_ALLOWED, msg); } else { resp.sendError(HttpServletResponse.SC_BAD_REQUEST, 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(HttpServletResponse.SC_METHOD_NOT_ALLOWED, msg); } else { resp.sendError(HttpServletResponse.SC_BAD_REQUEST, msg); } } private Method[] getAllDeclaredMethods(Class c) { if (c.getName().equals("javax.servlet.http.HttpServlet")) return null; int j = 0; Method[] parentMethods = getAllDeclaredMethods(c.getSuperclass()); Method[] thisMethods = c.getDeclaredMethods(); if (parentMethods != null) { Method[] allMethods = new Method[parentMethods.length + thisMethods.length]; for (int i = 0; i < parentMethods.length; i++) { allMethods[i] = parentMethods[i]; j = i; } j++; for (int i = j; i < thisMethods.length + j; i++) { allMethods[i] = thisMethods[i - j]; } return allMethods; } return thisMethods; } protected void doOptions(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { Method[] methods = getAllDeclaredMethods(this.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) if (allow == null) allow = METHOD_GET; if (ALLOW_HEAD) if (allow == null) allow = METHOD_HEAD; else allow += ", " + METHOD_HEAD; if (ALLOW_POST) if (allow == null) allow = METHOD_POST; else allow += ", " + METHOD_POST; if (ALLOW_PUT) if (allow == null) allow = METHOD_PUT; else allow += ", " + METHOD_PUT; if (ALLOW_DELETE) if (allow == null) allow = METHOD_DELETE; else allow += ", " + METHOD_DELETE; if (ALLOW_TRACE) if (allow == null) allow = METHOD_TRACE; else allow += ", " + METHOD_TRACE; if (ALLOW_OPTIONS) if (allow == null) allow = METHOD_OPTIONS; else allow += ", " + METHOD_OPTIONS; resp.setHeader("Allow", allow); } protected void doTrace(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { int responseLength; String CRLF = "\r\n"; String responseString = "TRACE " + req.getRequestURI() + " " + req.getProtocol(); Enumeration reqHeaderEnum = req.getHeaderNames(); while (reqHeaderEnum.hasMoreElements()) { String headerName = (String) reqHeaderEnum.nextElement(); responseString += CRLF + headerName + ": " + req.getHeader(headerName); } responseString += CRLF; responseLength = responseString.length(); resp.setContentType("message/http"); resp.setContentLength(responseLength); ServletOutputStream out = resp.getOutputStream(); out.print(responseString); out.close(); return; } protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { String method = req.getMethod(); if (method.equals(METHOD_GET)) { long lastModified = getLastModified(req); if (lastModified == -1) { // servlet doesn't support if-modified-since, no reason // to go through further expensive logic doGet(req, resp); } else { long ifModifiedSince = req.getDateHeader(HEADER_IFMODSINCE); if (ifModifiedSince < (lastModified / 1000 * 1000)) { // If the servlet mod time is later, call doGet() // Round down to the nearest second for a proper compare // A ifModifiedSince of -1 will always be less maybeSetLastModified(resp, lastModified); doGet(req, resp); } else { resp.setStatus(HttpServletResponse.SC_NOT_MODIFIED); } } } else if (method.equals(METHOD_HEAD)) { long lastModified = getLastModified(req); maybeSetLastModified(resp, lastModified); doHead(req, resp); } else if (method.equals(METHOD_POST)) { doPost(req, resp); } else if (method.equals(METHOD_PUT)) { doPut(req, resp); } else if (method.equals(METHOD_DELETE)) { doDelete(req, resp); } else if (method.equals(METHOD_OPTIONS)) { doOptions(req, resp); } else if (method.equals(METHOD_TRACE)) { doTrace(req, resp); } else { // // Note that this means NO servlet supports whatever // method was requested, anywhere on this server. // String errMsg = lStrings.getString("http.method_not_implemented"); Object[] errArgs = new Object[1]; errArgs[0] = method; errMsg = MessageFormat.format(errMsg, errArgs); resp.sendError(HttpServletResponse.SC_NOT_IMPLEMENTED, errMsg); } } private void maybeSetLastModified(HttpServletResponse resp, long lastModified) { if (resp.containsHeader(HEADER_LASTMOD)) return; if (lastModified >= 0) resp.setDateHeader(HEADER_LASTMOD, 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); } }
スプリングコンテナバー
アプリケーションContextクラスが
動作原理
Spring boot & Sevlet
ばね起動実行プロセス
@Configuration @Conditional({DispatcherServletAutoConfiguration.DefaultDispatcherServletCondition.class}) @ConditionalOnClass({ServletRegistration.class}) @EnableConfigurationProperties({HttpProperties.class, WebMvcProperties.class}) protected static class DispatcherServletConfiguration { private final HttpProperties httpProperties; private final WebMvcProperties webMvcProperties; public DispatcherServletConfiguration(HttpProperties httpProperties, WebMvcProperties webMvcProperties) { this.httpProperties = httpProperties; this.webMvcProperties = webMvcProperties; } @Bean( name = {"dispatcherServlet"} ) public DispatcherServlet dispatcherServlet() { DispatcherServlet dispatcherServlet = new DispatcherServlet(); dispatcherServlet.setDispatchOptionsRequest(this.webMvcProperties.isDispatchOptionsRequest()); dispatcherServlet.setDispatchTraceRequest(this.webMvcProperties.isDispatchTraceRequest()); dispatcherServlet.setThrowExceptionIfNoHandlerFound(this.webMvcProperties.isThrowExceptionIfNoHandlerFound()); dispatcherServlet.setEnableLoggingRequestDetails(this.httpProperties.isLogRequestDetails()); return dispatcherServlet; } @Bean @ConditionalOnBean({MultipartResolver.class}) @ConditionalOnMissingBean( name = {"multipartResolver"} ) public MultipartResolver multipartResolver(MultipartResolver resolver) { return resolver; } }
クライアントからDispatcherServiceletへのリクエスト
Application context
Dispatcherサーブレットの作成には注意が必要です.Dispatcherテンプレートを生成すると、WebApplicationContextが生成されます.一つはDispatchで生成されたWebApplicationContext、もう一つはSpringでContextLoaderで生成されたRootWebApplicationContextです.この二人は親子関係だ.構造は以下のようにすることができる.これにより、スプリングは最終的に次のような構造に転向する.上記の構成理由は、RootWebApplicationContextを共有するために複数のDispatcherServiceを登録するために使用することができる.
Reference
この問題について((3):スプリングの動き方について), 我々は、より多くの情報をここで見つけました https://velog.io/@lshn1007/Spring-3-스프링-동작방식에-관하여テキストは自由に共有またはコピーできます。ただし、このドキュメントのURLは参考URLとして残しておいてください。
Collection and Share based on the CC Protocol