request获取容器过程

获取容器过程
 
CoyoteAdapter.postParseRequest(org.apache.coyote.Request req, Request request,
            org.apache.coyote.Response res, Response response)
 
connector.getService().getMapper().map(serverName, decodedURI,
                    version, request.getMappingData());
 
Mapper.map
 
public void map(MessageBytes host, MessageBytes uri, String version,
                    MappingData mappingData) throws IOException {
 
        if (host.isNull()) {
            host.getCharChunk().append(defaultHostName);
        }
        host.toChars();
        uri.toChars();
        internalMap(host.getCharChunk(), uri.getCharChunk(), version,
                mappingData);
    }
 
Mapper.internalMap
 
 private final void internalMap(CharChunk host, CharChunk uri,
            String version, MappingData mappingData) throws IOException {
 
        if (mappingData.host != null) {
            // The legacy code (dating down at least to Tomcat 4.1) just
            // skipped all mapping work in this case. That behaviour has a risk
            // of returning an inconsistent result.
            // I do not see a valid use case for it.
            throw new AssertionError();
        }
 
        uri.setLimit(-1);
        // Virtual host mapping
        MappedHost[] hosts = this.hosts;
//根据host域名精确查找host
        MappedHost mappedHost = exactFindIgnoreCase(hosts, host);
        if (mappedHost == null) {
            // Note: Internally, the Mapper does not use the leading * on a
            //       wildcard host. This is to allow this shortcut.
//*.apache.org --> .apache.org，通过这个去查找
            int firstDot = host.indexOf('.');
            if (firstDot > -1) {
                int offset = host.getOffset();
                try {
                    host.setOffset(firstDot + offset);
                    mappedHost = exactFindIgnoreCase(hosts, host);
                } finally {
                    // Make absolutely sure this gets reset
                    host.setOffset(offset);
                }
            }
            if (mappedHost == null) {
                mappedHost = defaultHost;//如果没有找到就使用默认host
                if (mappedHost == null) {
                    return;
                }
            }
        }
        mappingData.host = mappedHost.object;
 
        // Context mapping 前缀匹配
        ContextList contextList = mappedHost.contextList;
        MappedContext[] contexts = contextList.contexts;
        int pos = find(contexts, uri);
        if (pos == -1) {
            return;
        }
 
        int lastSlash = -1;
        int uriEnd = uri.getEnd();
        int length = -1;
        boolean found = false;
        MappedContext context = null;
        while (pos >= 0) {
            context = contexts[pos];
            if (uri.startsWith(context.name)) {
//如果长度一样直接表示找到匹配的对象
                length = context.name.length();
                if (uri.getLength() == length) {
                    found = true;
                    break;
                } else if (uri.startsWithIgnoreCase("/", length)) {
                    found = true;
                    break;
                }
            }
//查找最后一个/的位置（匹配最长的路径），然后从开始到这个点进行匹配
            if (lastSlash == -1) {
                lastSlash = nthSlash(uri, contextList.nesting + 1);
            } else {
                lastSlash = lastSlash(uri);
            }
            uri.setEnd(lastSlash);
            pos = find(contexts, uri);
        }
        uri.setEnd(uriEnd);
 
        if (!found) {
//如果没有找打，使用默认的context，如果连默认的都没有直接返回null
            if (contexts[0].name.equals("")) {
                context = contexts[0];
            } else {
                context = null;
            }
        }
        if (context == null) {
            return;
        }
 
        mappingData.contextPath.setString(context.name);
 
        ContextVersion contextVersion = null;
        ContextVersion[] contextVersions = context.versions;
        final int versionCount = contextVersions.length;
        if (versionCount > 1) {
            Context[] contextObjects = new Context[contextVersions.length];
            for (int i = 0; i < contextObjects.length; i++) {
                contextObjects[i] = contextVersions[i].object;
            }
            mappingData.contexts = contextObjects;
            if (version != null) {
//精确查找版本
                contextVersion = exactFind(contextVersions, version);
            }
        }
        if (contextVersion == null) {
            // Return the latest version
            // The versions array is known to contain at least one element
            contextVersion = contextVersions[versionCount - 1];
        }
        mappingData.context = contextVersion.object;
        mappingData.contextSlashCount = contextVersion.slashCount;
 
        // Wrapper mapping
        if (!contextVersion.isPaused()) {
            internalMapWrapper(contextVersion, uri, mappingData);
        }
 
    }
 
Mapper.internalMapWrapper
 
private final void internalMapWrapper(ContextVersion contextVersion,
                                          CharChunk path,
                                          MappingData mappingData) throws IOException {
 
        int pathOffset = path.getOffset();
        int pathEnd = path.getEnd();
        boolean noServletPath = false;
 
        int length = contextVersion.path.length();
        if (length == (pathEnd - pathOffset)) {
            noServletPath = true;//如果请求路径和context路径一样长，那么就表示没有servletPath，这种路径一般是使用默认的index页面
        }
        int servletPath = pathOffset + length;
        path.setOffset(servletPath);//设置servlet路径，比如localhost:8080/test/index --> servlet路径为index，那么偏移地址为index第一个字符的下标
 
        // Rule 1 -- Exact Match 精确匹配
        MappedWrapper[] exactWrappers = contextVersion.exactWrappers;
        internalMapExactWrapper(exactWrappers, path, mappingData);
 
        // Rule 2 -- Prefix Match 前缀匹配，这里的匹配和context的匹配方式一样
        boolean checkJspWelcomeFiles = false;
        MappedWrapper[] wildcardWrappers = contextVersion.wildcardWrappers;
        if (mappingData.wrapper == null) {
            internalMapWildcardWrapper(wildcardWrappers, contextVersion.nesting,
                                       path, mappingData);
            if (mappingData.wrapper != null && mappingData.jspWildCard) {
                char[] buf = path.getBuffer();
                if (buf[pathEnd - 1] == '/') {
                    /*
                     * Path ending in '/' was mapped to JSP servlet based on
                     * wildcard match (e.g., as specified in url-pattern of a
                     * jsp-property-group.
                     * Force the context's welcome files, which are interpreted
                     * as JSP files (since they match the url-pattern), to be
                     * considered. See Bugzilla 27664.
                     */
                    mappingData.wrapper = null;
                    checkJspWelcomeFiles = true;
                } else {
                    // See Bugzilla 27704
                    mappingData.wrapperPath.setChars(buf, path.getStart(),
                                                     path.getLength());
                    mappingData.pathInfo.recycle();
                }
            }
        }
 
        if(mappingData.wrapper == null && noServletPath &&
                contextVersion.object.getMapperContextRootRedirectEnabled()) {
            // The path is empty, redirect to "/"
            path.append('/');
            pathEnd = path.getEnd();
            mappingData.redirectPath.setChars
                (path.getBuffer(), pathOffset, pathEnd - pathOffset);
            path.setEnd(pathEnd - 1);
            return;
        }
 
        // Rule 3 -- Extension Match
        MappedWrapper[] extensionWrappers = contextVersion.extensionWrappers;
        if (mappingData.wrapper == null && !checkJspWelcomeFiles) {
            internalMapExtensionWrapper(extensionWrappers, path, mappingData,
                    true);
        }
 
        // Rule 4 -- Welcome resources processing for servlets
        if (mappingData.wrapper == null) {
            boolean checkWelcomeFiles = checkJspWelcomeFiles;
            if (!checkWelcomeFiles) {
                char[] buf = path.getBuffer();
                checkWelcomeFiles = (buf[pathEnd - 1] == '/');
            }
            if (checkWelcomeFiles) {
                for (int i = 0; (i < contextVersion.welcomeResources.length)
                         && (mappingData.wrapper == null); i++) {
                    path.setOffset(pathOffset);
                    path.setEnd(pathEnd);
                    path.append(contextVersion.welcomeResources[i], 0,
                            contextVersion.welcomeResources[i].length());
                    path.setOffset(servletPath);
 
                    // Rule 4a -- Welcome resources processing for exact macth
                    internalMapExactWrapper(exactWrappers, path, mappingData);
 
                    // Rule 4b -- Welcome resources processing for prefix match
                    if (mappingData.wrapper == null) {
                        internalMapWildcardWrapper
                            (wildcardWrappers, contextVersion.nesting,
                             path, mappingData);
                    }
 
                    // Rule 4c -- Welcome resources processing
                    //            for physical folder
                    if (mappingData.wrapper == null
                        && contextVersion.resources != null) {
                        String pathStr = path.toString();
                        WebResource file =
                                contextVersion.resources.getResource(pathStr);
                        if (file != null && file.isFile()) {
                            internalMapExtensionWrapper(extensionWrappers, path,
                                                        mappingData, true);
                            if (mappingData.wrapper == null
                                && contextVersion.defaultWrapper != null) {
                                mappingData.wrapper =
                                    contextVersion.defaultWrapper.object;
                                mappingData.requestPath.setChars
                                    (path.getBuffer(), path.getStart(),
                                     path.getLength());
                                mappingData.wrapperPath.setChars
                                    (path.getBuffer(), path.getStart(),
                                     path.getLength());
                                mappingData.requestPath.setString(pathStr);
                                mappingData.wrapperPath.setString(pathStr);
                            }
                        }
                    }
                }
 
                path.setOffset(servletPath);
                path.setEnd(pathEnd);
            }
 
        }
 
        /* welcome file processing - take 2
         * Now that we have looked for welcome files with a physical
         * backing, now look for an extension mapping listed
         * but may not have a physical backing to it. This is for
         * the case of index.jsf, index.do, etc.
         * A watered down version of rule 4
         */
        if (mappingData.wrapper == null) {
            boolean checkWelcomeFiles = checkJspWelcomeFiles;
            if (!checkWelcomeFiles) {
                char[] buf = path.getBuffer();
                checkWelcomeFiles = (buf[pathEnd - 1] == '/');
            }
            if (checkWelcomeFiles) {
                for (int i = 0; (i < contextVersion.welcomeResources.length)
                         && (mappingData.wrapper == null); i++) {
                    path.setOffset(pathOffset);
                    path.setEnd(pathEnd);
                    path.append(contextVersion.welcomeResources[i], 0,
                                contextVersion.welcomeResources[i].length());
                    path.setOffset(servletPath);
                    internalMapExtensionWrapper(extensionWrappers, path,
                                                mappingData, false);
                }
 
                path.setOffset(servletPath);
                path.setEnd(pathEnd);
            }
        }
 
        // Rule 7 -- Default servlet
        if (mappingData.wrapper == null && !checkJspWelcomeFiles) {
            if (contextVersion.defaultWrapper != null) {
                mappingData.wrapper = contextVersion.defaultWrapper.object;
                mappingData.requestPath.setChars
                    (path.getBuffer(), path.getStart(), path.getLength());
                mappingData.wrapperPath.setChars
                    (path.getBuffer(), path.getStart(), path.getLength());
                mappingData.matchType = MappingMatch.DEFAULT;
            }
            // Redirection to a folder
            char[] buf = path.getBuffer();
            if (contextVersion.resources != null && buf[pathEnd -1 ] != '/') {
                String pathStr = path.toString();
                WebResource file;
                // Handle context root
                if (pathStr.length() == 0) {
                    file = contextVersion.resources.getResource("/");
                } else {
                    file = contextVersion.resources.getResource(pathStr);
                }
                if (file != null && file.isDirectory() &&
                        contextVersion.object.getMapperDirectoryRedirectEnabled()) {
                    // Note: this mutates the path: do not do any processing
                    // after this (since we set the redirectPath, there
                    // shouldn't be any)
                    path.setOffset(pathOffset);
                    path.append('/');
                    mappingData.redirectPath.setChars
                        (path.getBuffer(), path.getStart(), path.getLength());
                } else {
                    mappingData.requestPath.setString(pathStr);
                    mappingData.wrapperPath.setString(pathStr);
                }
            }
        }
 
        path.setOffset(pathOffset);
        path.setEnd(pathEnd);
    }