Quelle HttpServlet.java Sprache: JAVA

/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package jakarta.servlet.http;

import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.UnsupportedEncodingException;
import java.io.Writer;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.text.MessageFormat;
import java.util.Arrays;
import java.util.Enumeration;
import java.util.List;
import java.util.Locale;
import java.util.ResourceBundle;

import jakarta.servlet.AsyncEvent;
import jakarta.servlet.AsyncListener;
import jakarta.servlet.DispatcherType;
import jakarta.servlet.GenericServlet;
import jakarta.servlet.ServletConfig;
import jakarta.servlet.ServletException;
import jakarta.servlet.ServletOutputStream;
import jakarta.servlet.ServletRequest;
import jakarta.servlet.ServletResponse;
import jakarta.servlet.WriteListener;

/**
* Provides an abstract class to be subclassed to create an HTTP servlet suitable for a Web site. A subclass of
* <code>HttpServlet</code> must override at least one method, usually one of these:
* <ul>
* <li><code>doGet</code>, if the servlet supports HTTP GET requests
* <li><code>doPost</code>, for HTTP POST requests
* <li><code>doPut</code>, for HTTP PUT requests
* <li><code>doDelete</code>, for HTTP DELETE requests
* <li><code>init</code> and <code>destroy</code>, to manage resources that are held for the life of the servlet
* <li><code>getServletInfo</code>, which the servlet uses to provide information about itself
* </ul>
* 
* There's almost no reason to override the <code>service</code> method. <code>service</code> handles standard HTTP
* requests by dispatching them to the handler methods for each HTTP request type (the <code>do</code>Method
* methods listed above).
* 
* Likewise, there's almost no reason to override the <code>doOptions</code> and <code>doTrace</code> methods.
* 
* Servlets typically run on multithreaded servers, so be aware that a servlet must handle concurrent requests and be
* careful to synchronize access to shared resources. Shared resources include in-memory data such as instance or class
* variables and external objects such as files, database connections, and network connections. See the
* <a href="http://java.sun.com/Series/Tutorial/java/threads/multithreaded.html"> Java Tutorial on Multithreaded
* Programming</a> for more information on handling multiple threads in a Java program.
*/
public abstract class HttpServlet extends GenericServlet {

 private static final long serialVersionUID = 1L;

 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 = "jakarta.servlet.http.LocalStrings";
 private static final ResourceBundle lStrings = ResourceBundle.getBundle(LSTRING_FILE);

 private static final List<String> SENSITIVE_HTTP_HEADERS =
 Arrays.asList("authorization", "cookie", "x-forwarded", "forwarded", "proxy-authorization");

 /**
 * @deprecated May be removed in a future release
 *
 * @since Servlet 6.0
 */
 @Deprecated(forRemoval = true, since = "Servlet 6.0")
 public static final String LEGACY_DO_HEAD = "jakarta.servlet.http.legacyDoHead";

 private final transient Object cachedAllowHeaderValueLock = new Object();

 /**
 * Cached value of the HTTP {@code Allow} header for this servlet.
 */
 private volatile String cachedAllowHeaderValue = null;

 /**
 * Cached value read from {@link HttpServlet#LEGACY_DO_HEAD} system property.
 */
 private volatile boolean cachedUseLegacyDoHead;

 /**
 * Does nothing, because this is an abstract class.
 */
 public HttpServlet() {
 // NOOP
 }

 @Override
 public void init(ServletConfig config) throws ServletException {
 super.init(config);
 cachedUseLegacyDoHead = Boolean.parseBoolean(config.getInitParameter(LEGACY_DO_HEAD));
 }

 /**
 * Called by the server (via the <code>service</code> method) to allow a servlet to handle a GET request.
 * 
 * Overriding this method to support a GET request also automatically supports an HTTP HEAD request. A HEAD request
 * is a GET request that returns no body in the response, only the request header fields.
 * 
 * When overriding this method, read the request data, write the response headers, get the response's Writer or
 * output stream object, and finally, write the response data. It's best to include content type and encoding. When
 * using a <code>PrintWriter</code> object to return the response, set the content type before accessing the
 * <code>PrintWriter</code> object.
 * 
 * The servlet container must write the headers before committing the response, because in HTTP the headers must be
 * sent before the response body.
 * 
 * Where possible, set the Content-Length header (with the {@link jakarta.servlet.ServletResponse#setContentLength}
 * method), to allow the servlet container to use a persistent connection to return its response to the client,
 * improving performance. The content length is automatically set if the entire response fits inside the response
 * buffer.
 * 
 * When using HTTP 1.1 chunked encoding (which means that the response has a Transfer-Encoding header), do not set
 * the Content-Length header.
 * 
 * The GET method should be safe, that is, without any side effects for which users are held responsible. For
 * example, most form queries have no side effects. If a client request is intended to change stored data, the
 * request should use some other HTTP method.
 * 
 * The GET method should also be idempotent, meaning that it can be safely repeated. Sometimes making a method safe
 * also makes it idempotent. For example, repeating queries is both safe and idempotent, but buying a product online
 * or modifying data is neither safe nor idempotent.
 * 
 * If the request is incorrectly formatted, <code>doGet</code> returns an HTTP "Bad Request" message.
 *
 * @param req an {@link HttpServletRequest} object that contains the request the client has made of the servlet
 * @param resp an {@link HttpServletResponse} object that contains the response the servlet sends to the client
 *
 * @exception IOException if an input or output error is detected when the servlet handles the GET request
 * @exception ServletException if the request for the GET could not be handled
 *
 * @see jakarta.servlet.ServletResponse#setContentType
 */
 protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
 String msg = lStrings.getString("http.method_get_not_supported");
 sendMethodNotAllowed(req, resp, msg);
 }

 /**
 * Returns the time the <code>HttpServletRequest</code> object was last modified, in milliseconds since midnight
 * January 1, 1970 GMT. If the time is unknown, this method returns a negative number (the default).
 * 
 * Servlets that support HTTP GET requests and can quickly determine their last modification time should override
 * this method. This makes browser and proxy caches work more effectively, reducing the load on server and network
 * resources.
 *
 * @param req the <code>HttpServletRequest</code> object that is sent to the servlet
 *
 * @return a <code>long</code> integer specifying the time the <code>HttpServletRequest</code> object was last
 * modified, in milliseconds since midnight, January 1, 1970 GMT, or -1 if the time is not known
 */
 protected long getLastModified(HttpServletRequest req) {
 return -1;
 }

 /**
 * 
 * Receives an HTTP HEAD request from the protected <code>service</code> method and handles the request. The client
 * sends a HEAD request when it wants to see only the headers of a response, such as Content-Type or Content-Length.
 * The HTTP HEAD method counts the output bytes in the response to set the Content-Length header accurately.
 * 
 * If you override this method, you can avoid computing the response body and just set the response headers directly
 * to improve performance. Make sure that the <code>doHead</code> method you write is both safe and idempotent (that
 * is, protects itself from being called multiple times for one HTTP HEAD request).
 * 
 * If the HTTP HEAD request is incorrectly formatted, <code>doHead</code> returns an HTTP "Bad Request" message.
 *
 * @param req the request object that is passed to the servlet
 * @param resp the response object that the servlet uses to return the headers to the client
 *
 * @exception IOException if an input or output error occurs
 * @exception ServletException if the request for the HEAD could not be handled
 */
 protected void doHead(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

 if (DispatcherType.INCLUDE.equals(req.getDispatcherType()) || !cachedUseLegacyDoHead) {
 doGet(req, resp);
 } else {
 NoBodyResponse response = new NoBodyResponse(resp);
 doGet(req, response);
 if (req.isAsyncStarted()) {
 req.getAsyncContext().addListener(new NoBodyAsyncContextListener(response));
 } else {
 response.setContentLength();
 }
 }
 }

 /**
 * Called by the server (via the <code>service</code> method) to allow a servlet to handle a POST request. The HTTP
 * POST method allows the client to send data of unlimited length to the Web server a single time and is useful when
 * posting information such as credit card numbers.
 * 
 * When overriding this method, read the request data, write the response headers, get the response's Writer or
 * output stream object, and finally, write the response data. It's best to include content type and encoding. When
 * using a <code>PrintWriter</code> object to return the response, set the content type before accessing the
 * <code>PrintWriter</code> object.
 * 
 * The servlet container must write the headers before committing the response, because in HTTP the headers must be
 * sent before the response body.
 * 
 * Where possible, set the Content-Length header (with the {@link jakarta.servlet.ServletResponse#setContentLength}
 * method), to allow the servlet container to use a persistent connection to return its response to the client,
 * improving performance. The content length is automatically set if the entire response fits inside the response
 * buffer.
 * 
 * When using HTTP 1.1 chunked encoding (which means that the response has a Transfer-Encoding header), do not set
 * the Content-Length header.
 * 
 * This method does not need to be either safe or idempotent. Operations requested through POST can have side
 * effects for which the user can be held accountable, for example, updating stored data or buying items online.
 * 
 * If the HTTP POST request is incorrectly formatted, <code>doPost</code> returns an HTTP "Bad Request" message.
 *
 * @param req an {@link HttpServletRequest} object that contains the request the client has made of the servlet
 * @param resp an {@link HttpServletResponse} object that contains the response the servlet sends to the client
 *
 * @exception IOException if an input or output error is detected when the servlet handles the request
 * @exception ServletException if the request for the POST could not be handled
 *
 * @see jakarta.servlet.ServletOutputStream
 * @see jakarta.servlet.ServletResponse#setContentType
 */
 protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

 String msg = lStrings.getString("http.method_post_not_supported");
 sendMethodNotAllowed(req, resp, msg);
 }

 /**
 * Called by the server (via the <code>service</code> method) to allow a servlet to handle a PUT request. The PUT
 * operation allows a client to place a file on the server and is similar to sending a file by FTP.
 * 
 * When overriding this method, leave intact any content headers sent with the request (including Content-Length,
 * Content-Type, Content-Transfer-Encoding, Content-Encoding, Content-Base, Content-Language, Content-Location,
 * Content-MD5, and Content-Range). If your method cannot handle a content header, it must issue an error message
 * (HTTP 501 - Not Implemented) and discard the request. For more information on HTTP 1.1, see RFC 2616
 * <a href="http://www.ietf.org/rfc/rfc2616.txt"></a>.
 * 
 * This method does not need to be either safe or idempotent. Operations that <code>doPut</code> performs can have
 * side effects for which the user can be held accountable. When using this method, it may be useful to save a copy
 * of the affected URL in temporary storage.
 * 
 * If the HTTP PUT request is incorrectly formatted, <code>doPut</code> returns an HTTP "Bad Request" message.
 *
 * @param req the {@link HttpServletRequest} object that contains the request the client made of the servlet
 * @param resp the {@link HttpServletResponse} object that contains the response the servlet returns to the client
 *
 * @exception IOException if an input or output error occurs while the servlet is handling the PUT request
 * @exception ServletException if the request for the PUT cannot be handled
 */
 protected void doPut(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

 String msg = lStrings.getString("http.method_put_not_supported");
 sendMethodNotAllowed(req, resp, msg);
 }

 /**
 * Called by the server (via the <code>service</code> method) to allow a servlet to handle a DELETE request. The
 * DELETE operation allows a client to remove a document or Web page from the server.
 * 
 * This method does not need to be either safe or idempotent. Operations requested through DELETE can have side
 * effects for which users can be held accountable. When using this method, it may be useful to save a copy of the
 * affected URL in temporary storage.
 * 
 * If the HTTP DELETE request is incorrectly formatted, <code>doDelete</code> returns an HTTP "Bad Request" message.
 *
 * @param req the {@link HttpServletRequest} object that contains the request the client made of the servlet
 * @param resp the {@link HttpServletResponse} object that contains the response the servlet returns to the client
 *
 * @exception IOException if an input or output error occurs while the servlet is handling the DELETE request
 * @exception ServletException if the request for the DELETE cannot be handled
 */
 protected void doDelete(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

 String msg = lStrings.getString("http.method_delete_not_supported");
 sendMethodNotAllowed(req, resp, msg);
 }

 private void sendMethodNotAllowed(HttpServletRequest req, HttpServletResponse resp, String msg) throws IOException {
 String protocol = req.getProtocol();
 // Note: Tomcat reports "" for HTTP/0.9 although some implementations
 // may report HTTP/0.9
 if (protocol.length() == 0 || protocol.endsWith("0.9") || protocol.endsWith("1.0")) {
 resp.sendError(HttpServletResponse.SC_BAD_REQUEST, msg);
 } else {
 resp.sendError(HttpServletResponse.SC_METHOD_NOT_ALLOWED, msg);
 }
 }

 private String getCachedAllowHeaderValue() {
 if (cachedAllowHeaderValue == null) {
 synchronized (cachedAllowHeaderValueLock) {
 if (cachedAllowHeaderValue == null) {

 Method[] methods = getAllDeclaredMethods(this.getClass());

 // RFC 7230 does not define an order for this header
 // This code aims to retain, broadly, the order of method
 // tokens returned in earlier versions of this code. If that
 // constraint is dropped then the code can be simplified
 // further.

 boolean allowGet = false;
 boolean allowHead = false;
 boolean allowPost = false;
 boolean allowPut = false;
 boolean allowDelete = false;

 for (Method method : methods) {
 switch (method.getName()) {
 case "doGet": {
 allowGet = true;
 allowHead = true;
 break;
 }
 case "doPost": {
 allowPost = true;
 break;
 }
 case "doPut": {
 allowPut = true;
 break;
 }
 case "doDelete": {
 allowDelete = true;
 break;
 }
 default:
 // NO-OP
 }

 }

 StringBuilder allow = new StringBuilder();

 if (allowGet) {
 allow.append(METHOD_GET);
 allow.append(", ");
 }

 if (allowHead) {
 allow.append(METHOD_HEAD);
 allow.append(", ");
 }

 if (allowPost) {
 allow.append(METHOD_POST);
 allow.append(", ");
 }

 if (allowPut) {
 allow.append(METHOD_PUT);
 allow.append(", ");
 }

 if (allowDelete) {
 allow.append(METHOD_DELETE);
 allow.append(", ");
 }

 // Options is always allowed
 allow.append(METHOD_OPTIONS);

 cachedAllowHeaderValue = allow.toString();
 }
 }
 }

 return cachedAllowHeaderValue;
 }

 private static 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;
 }

 /**
 * Called by the server (via the <code>service</code> method) to allow a servlet to handle an OPTIONS request. The
 * OPTIONS request determines which HTTP methods the server supports and returns an appropriate header. For example,
 * if a servlet overrides <code>doGet</code>, this method returns the following header:
 * 
 * <code>Allow: GET, HEAD, TRACE, OPTIONS</code>
 * 
 * There's no need to override this method unless the servlet implements new HTTP methods, beyond those implemented
 * by HTTP 1.1.
 *
 * @param req the {@link HttpServletRequest} object that contains the request the client made of the servlet
 * @param resp the {@link HttpServletResponse} object that contains the response the servlet returns to the client
 *
 * @exception IOException if an input or output error occurs while the servlet is handling the OPTIONS request
 * @exception ServletException if the request for the OPTIONS cannot be handled
 */
 protected void doOptions(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

 String allow = getCachedAllowHeaderValue();

 // Tomcat specific hack to see if TRACE is allowed
 if (TomcatHack.getAllowTrace(req)) {
 if (allow.length() == 0) {
 allow = METHOD_TRACE;
 } else {
 allow = allow + ", " + METHOD_TRACE;
 }
 }

 resp.setHeader("Allow", allow);
 }

 /**
 * Called by the server (via the <code>service</code> method) to allow a servlet to handle a TRACE request. A TRACE
 * returns the headers sent with the TRACE request to the client, so that they can be used in debugging. There's no
 * need to override this method.
 *
 * @param req the {@link HttpServletRequest} object that contains the request the client made of the servlet
 * @param resp the {@link HttpServletResponse} object that contains the response the servlet returns to the client
 *
 * @exception IOException if an input or output error occurs while the servlet is handling the TRACE request
 * @exception ServletException if the request for the TRACE cannot be handled
 */
 protected void doTrace(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

 int responseLength;

 String CRLF = "\r\n";
 StringBuilder buffer =
 new StringBuilder("TRACE ").append(req.getRequestURI()).append(' ').append(req.getProtocol());

 Enumeration<String> reqHeaderNames = req.getHeaderNames();

 while (reqHeaderNames.hasMoreElements()) {
 String headerName = reqHeaderNames.nextElement();
 // RFC 7231, 4.3.8 - skip 'sensitive' headers
 if (!isSensitiveHeader(headerName)) {
 Enumeration<String> headerValues = req.getHeaders(headerName);
 while (headerValues.hasMoreElements()) {
 String headerValue = headerValues.nextElement();
 buffer.append(CRLF).append(headerName).append(": ").append(headerValue);
 }
 }
 }

 buffer.append(CRLF);

 responseLength = buffer.length();

 resp.setContentType("message/http");
 resp.setContentLength(responseLength);
 ServletOutputStream out = resp.getOutputStream();
 out.print(buffer.toString());
 out.close();
 }

 /**
 * Is the provided HTTP request header considered sensitive and therefore should be excluded from the response to a
 * {@code TRACE} request?
 * 
 * By default, the headers that start with any of the following are considered sensitive:
 * <ul>
 * <li>authorization</li>
 * <li>cookie</li>
 * <li>x-forwarded</li>
 * <li>forwarded</li>
 * <li>proxy-authorization</li>
 * </ul>
 * 
 * Note that HTTP header names are case insensitive.
 *
 * @param headerName the name of the HTTP request header to test
 *
 * @return (@code true} if the HTTP request header is considered sensitive and should be excluded from the response
 * to a {@code TRACE} request, otherwise {@code false}
 */
 private boolean isSensitiveHeader(String headerName) {
 String lcHeaderName = headerName.toLowerCase(Locale.ENGLISH);
 for (String sensitiveHeaderName : SENSITIVE_HTTP_HEADERS) {
 if (lcHeaderName.startsWith(sensitiveHeaderName)) {
 return true;
 }
 }
 return false;
 }

 /**
 * Receives standard HTTP requests from the public <code>service</code> method and dispatches them to the
 * <code>do</code>Method methods defined in this class. This method is an HTTP-specific version of the
 * {@link jakarta.servlet.Servlet#service} method. There's no need to override this method.
 *
 * @param req the {@link HttpServletRequest} object that contains the request the client made of the servlet
 * @param resp the {@link HttpServletResponse} object that contains the response the servlet returns to the client
 *
 * @exception IOException if an input or output error occurs while the servlet is handling the HTTP request
 * @exception ServletException if the HTTP request cannot be handled
 *
 * @see jakarta.servlet.Servlet#service
 */
 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;
 try {
 ifModifiedSince = req.getDateHeader(HEADER_IFMODSINCE);
 } catch (IllegalArgumentException iae) {
 // Invalid date header - proceed as if none was set
 ifModifiedSince = -1;
 }
 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);
 }
 }

 /*
 * Sets the Last-Modified entity header field, if it has not already been set and if the value is meaningful. Called
 * before doGet, to ensure that headers are set before response data is written. A subclass might have set this
 * header already, so we check.
 */
 private void maybeSetLastModified(HttpServletResponse resp, long lastModified) {
 if (resp.containsHeader(HEADER_LASTMOD)) {
 return;
 }
 if (lastModified >= 0) {
 resp.setDateHeader(HEADER_LASTMOD, lastModified);
 }
 }

 /**
 * Dispatches client requests to the protected <code>service</code> method. There's no need to override this method.
 *
 * @param req the {@link HttpServletRequest} object that contains the request the client made of the servlet
 * @param res the {@link HttpServletResponse} object that contains the response the servlet returns to the client
 *
 * @exception IOException if an input or output error occurs while the servlet is handling the HTTP request
 * @exception ServletException if the HTTP request cannot be handled
 *
 * @see jakarta.servlet.Servlet#service
 */
 @Override
 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(lStrings.getString("http.non_http"));
 }
 service(request, response);
 }

 private static class TomcatHack {

 private static final Class<?> REQUEST_FACADE_CLAZZ;
 private static final Method GET_ALLOW_TRACE;

 static {
 Method m1 = null;
 Class<?> c1 = null;
 try {
 c1 = Class.forName("org.apache.catalina.connector.RequestFacade");
 m1 = c1.getMethod("getAllowTrace", (Class<?>[]) null);
 } catch (ReflectiveOperationException | SecurityException | IllegalArgumentException e) {
 // Ignore. Not running on Tomcat. TRACE is always allowed.
 }
 REQUEST_FACADE_CLAZZ = c1;
 GET_ALLOW_TRACE = m1;
 }

 public static boolean getAllowTrace(HttpServletRequest req) {
 if (REQUEST_FACADE_CLAZZ != null && GET_ALLOW_TRACE != null) {
 if (REQUEST_FACADE_CLAZZ.isAssignableFrom(req.getClass())) {
 try {
 return ((Boolean) GET_ALLOW_TRACE.invoke(req, (Object[]) null)).booleanValue();
 } catch (IllegalAccessException | IllegalArgumentException | InvocationTargetException e) {
 // Should never happen given the checks in place.
 // Ignore
 }
 }
 }
 return true;
 }
 }

 /*
 * A response wrapper for use in (dumb) "HEAD" support. This just swallows that body, counting the bytes in order to
 * set the content length appropriately. All other methods delegate to the wrapped HTTP Servlet Response object.
 */
 private static class NoBodyResponse extends HttpServletResponseWrapper {
 private final NoBodyOutputStream noBodyOutputStream;
 private ServletOutputStream originalOutputStream;
 private NoBodyPrintWriter noBodyWriter;
 private boolean didSetContentLength;

 private NoBodyResponse(HttpServletResponse r) {
 super(r);
 noBodyOutputStream = new NoBodyOutputStream(this);
 }

 private void setContentLength() {
 if (!didSetContentLength) {
 if (noBodyWriter != null) {
 noBodyWriter.flush();
 }
 super.setContentLengthLong(noBodyOutputStream.getWrittenByteCount());
 }
 }

 @Override
 public void setContentLength(int len) {
 super.setContentLength(len);
 didSetContentLength = true;
 }

 @Override
 public void setContentLengthLong(long len) {
 super.setContentLengthLong(len);
 didSetContentLength = true;
 }

 @Override
 public void setHeader(String name, String value) {
 super.setHeader(name, value);
 checkHeader(name);
 }

 @Override
 public void addHeader(String name, String value) {
 super.addHeader(name, value);
 checkHeader(name);
 }

 @Override
 public void setIntHeader(String name, int value) {
 super.setIntHeader(name, value);
 checkHeader(name);
 }

 @Override
 public void addIntHeader(String name, int value) {
 super.addIntHeader(name, value);
 checkHeader(name);
 }

 private void checkHeader(String name) {
 if ("content-length".equalsIgnoreCase(name)) {
 didSetContentLength = true;
 }
 }

 @Override
 public ServletOutputStream getOutputStream() throws IOException {
 originalOutputStream = getResponse().getOutputStream();
 return noBodyOutputStream;
 }

 @Override
 public PrintWriter getWriter() throws UnsupportedEncodingException {

 if (noBodyWriter == null) {
 noBodyWriter = new NoBodyPrintWriter(noBodyOutputStream, getCharacterEncoding());
 }
 return noBodyWriter;
 }

 @Override
 public void reset() {
 super.reset();
 resetBuffer();
 originalOutputStream = null;
 }

 @Override
 public void resetBuffer() {
 noBodyOutputStream.resetBuffer();
 if (noBodyWriter != null) {
 noBodyWriter.resetBuffer();
 }
 }
 }

 /*
 * Servlet output stream that gobbles up all its data.
 */
 private static class NoBodyOutputStream extends ServletOutputStream {

 private static final String LSTRING_FILE = "jakarta.servlet.http.LocalStrings";
 private static final ResourceBundle lStrings = ResourceBundle.getBundle(LSTRING_FILE);

 private final NoBodyResponse response;
 private boolean flushed = false;
 private long writtenByteCount = 0;

 private NoBodyOutputStream(NoBodyResponse response) {
 this.response = response;
 }

 private long getWrittenByteCount() {
 return writtenByteCount;
 }

 @Override
 public void write(int b) throws IOException {
 writtenByteCount++;
 checkCommit();
 }

 @Override
 public void write(byte buf[], int offset, int len) throws IOException {
 if (buf == null) {
 throw new NullPointerException(lStrings.getString("err.io.nullArray"));
 }

 if (offset < 0 || len < 0 || offset + len > buf.length) {
 String msg = lStrings.getString("err.io.indexOutOfBounds");
 Object[] msgArgs = new Object[3];
 msgArgs[0] = Integer.valueOf(offset);
 msgArgs[1] = Integer.valueOf(len);
 msgArgs[2] = Integer.valueOf(buf.length);
 msg = MessageFormat.format(msg, msgArgs);
 throw new IndexOutOfBoundsException(msg);
 }

 writtenByteCount += len;
 checkCommit();
 }

 @Override
 public boolean isReady() {
 // Will always be ready as data is swallowed.
 return true;
 }

 @Override
 public void setWriteListener(WriteListener listener) {
 response.originalOutputStream.setWriteListener(listener);
 }

 private void checkCommit() throws IOException {
 if (!flushed && writtenByteCount > response.getBufferSize()) {
 response.flushBuffer();
 flushed = true;
 }
 }

 private void resetBuffer() {
 if (flushed) {
 throw new IllegalStateException(lStrings.getString("err.state.commit"));
 }
 writtenByteCount = 0;
 }
 }

 /*
 * On reset() and resetBuffer() need to clear the data buffered in the OutputStreamWriter. No easy way to do that so
 * NoBodyPrintWriter wraps a PrintWriter than can be thrown away on reset()/resetBuffer() and a new one constructed
 * while the application retains a reference to the NoBodyPrintWriter instance.
 */
 private static class NoBodyPrintWriter extends PrintWriter {

 private final NoBodyOutputStream out;
 private final String encoding;
 private PrintWriter pw;

 NoBodyPrintWriter(NoBodyOutputStream out, String encoding) throws UnsupportedEncodingException {
 super(out);
 this.out = out;
 this.encoding = encoding;

 Writer osw = new OutputStreamWriter(out, encoding);
 pw = new PrintWriter(osw);
 }

 private void resetBuffer() {
 out.resetBuffer();

 Writer osw = null;
 try {
 osw = new OutputStreamWriter(out, encoding);
 } catch (UnsupportedEncodingException e) {
 // Impossible.
 // The same values were used in the constructor. If this method
 // gets called then the constructor must have succeeded so the
 // above call must also succeed.
 }
 pw = new PrintWriter(osw);
 }

 @Override
 public void flush() {
 pw.flush();
 }

 @Override
 public void close() {
 pw.close();
 }

 @Override
 public boolean checkError() {
 return pw.checkError();
 }

 @Override
 public void write(int c) {
 pw.write(c);
 }

 @Override
 public void write(char[] buf, int off, int len) {
 pw.write(buf, off, len);
 }

 @Override
 public void write(char[] buf) {
 pw.write(buf);
 }

 @Override
 public void write(String s, int off, int len) {
 pw.write(s, off, len);
 }

 @Override
 public void write(String s) {
 pw.write(s);
 }

 @Override
 public void print(boolean b) {
 pw.print(b);
 }

 @Override
 public void print(char c) {
 pw.print(c);
 }

 @Override
 public void print(int i) {
 pw.print(i);
 }

 @Override
 public void print(long l) {
 pw.print(l);
 }

 @Override
 public void print(float f) {
 pw.print(f);
 }

 @Override
 public void print(double d) {
 pw.print(d);
 }

 @Override
 public void print(char[] s) {
 pw.print(s);
 }

 @Override
 public void print(String s) {
 pw.print(s);
 }

 @Override
 public void print(Object obj) {
 pw.print(obj);
 }

 @Override
 public void println() {
 pw.println();
 }

 @Override
 public void println(boolean x) {
 pw.println(x);
 }

 @Override
 public void println(char x) {
 pw.println(x);
 }

 @Override
 public void println(int x) {
 pw.println(x);
 }

 @Override
 public void println(long x) {
 pw.println(x);
 }

 @Override
 public void println(float x) {
 pw.println(x);
 }

 @Override
 public void println(double x) {
 pw.println(x);
 }

 @Override
 public void println(char[] x) {
 pw.println(x);
 }

 @Override
 public void println(String x) {
 pw.println(x);
 }

 @Override
 public void println(Object x) {
 pw.println(x);
 }
 }

 /*
 * Calls NoBodyResponse.setContentLength() once the async request is complete.
 */
 private static class NoBodyAsyncContextListener implements AsyncListener {

 private final NoBodyResponse noBodyResponse;

 NoBodyAsyncContextListener(NoBodyResponse noBodyResponse) {
 this.noBodyResponse = noBodyResponse;
 }

 @Override
 public void onComplete(AsyncEvent event) throws IOException {
 noBodyResponse.setContentLength();
 }

 @Override
 public void onTimeout(AsyncEvent event) throws IOException {
 // NO-OP
 }

 @Override
 public void onError(AsyncEvent event) throws IOException {
 // NO-OP
 }

 @Override
 public void onStartAsync(AsyncEvent event) throws IOException {
 // NO-OP
 }
 }
}

Messung V0.5 in Prozent

¤ Diese beiden folgenden Angebotsgruppen bietet das Unternehmen0.31Angebot (Wie Sie bei der Firma Beratungs- und Dienstleistungen beauftragen können 2026-09-30) ¤

*Eine klare Vorstellung vom Zielzustand

Wurzel

Suchen

PVS Prover

Isabelle Prover

NIST Cobol Testsuite

Cephes Mathematical Library

Vienna Development Method

Haftungshinweis

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Bemerkung:

Die farbliche Syntaxdarstellung und die Messung sind noch experimentell.