tomcat源码阅读13

StandardManager类的doLoad()方法，该方法从session文件中读取session对象，将其放入 protected Map<String, Session> sessions = new ConcurrentHashMap<String, Session>();中：

    protected void doLoad() throws ClassNotFoundException, IOException {
        if (log.isDebugEnabled())
            log.debug("Start: Loading persisted sessions");

        // Initialize our internal data structures
        sessions.clear();

        // Open an input stream to the specified pathname, if any
        File file = file();
        if (file == null)
            return;
        if (log.isDebugEnabled())
            log.debug(sm.getString("standardManager.loading", pathname));
        FileInputStream fis = null;
        ObjectInputStream ois = null;
        Loader loader = null;
        ClassLoader classLoader = null;
        try {
            fis = new FileInputStream(file.getAbsolutePath());
            BufferedInputStream bis = new BufferedInputStream(fis);
            if (container != null)
                loader = container.getLoader();
            if (loader != null)
                classLoader = loader.getClassLoader();
            if (classLoader != null) {
                if (log.isDebugEnabled())
                    log.debug("Creating custom object input stream for class loader ");
                ois = new CustomObjectInputStream(bis, classLoader);
            } else {
                if (log.isDebugEnabled())
                    log.debug("Creating standard object input stream");
                ois = new ObjectInputStream(bis);
            }
        } catch (FileNotFoundException e) {
            if (log.isDebugEnabled())
                log.debug("No persisted data file found");
            return;
        } catch (IOException e) {
            log.error(sm.getString("standardManager.loading.ioe", e), e);
            if (ois != null) {
                try {
                    ois.close();
                } catch (IOException f) {
                    ;
                }
                ois = null;
            }
            throw e;
        }

        // Load the previously unloaded active sessions
        synchronized (sessions) {
            try {
                Integer count = (Integer) ois.readObject();
                int n = count.intValue();
                if (log.isDebugEnabled())
                    log.debug("Loading " + n + " persisted sessions");
                for (int i = 0; i < n; i++) {
                    StandardSession session = getNewSession();
                    session.readObjectData(ois);
                    session.setManager(this);
                    sessions.put(session.getIdInternal(), session);
                    session.activate();
                    sessionCounter++;
                }
            } catch (ClassNotFoundException e) {
                log.error(sm.getString("standardManager.loading.cnfe", e), e);
                if (ois != null) {
                    try {
                        ois.close();
                    } catch (IOException f) {
                        ;
                    }
                    ois = null;
                }
                throw e;
            } catch (IOException e) {
                log.error(sm.getString("standardManager.loading.ioe", e), e);
                if (ois != null) {
                    try {
                        ois.close();
                    } catch (IOException f) {
                        ;
                    }
                    ois = null;
                }
                throw e;
            } finally {
                // Close the input stream
                try {
                    if (ois != null)
                        ois.close();
                } catch (IOException f) {
                    // ignored
                }

                // Delete the persistent storage file
                if (file != null && file.exists() )
                    file.delete();
            }
        }

        if (log.isDebugEnabled())
            log.debug("Finish: Loading persisted sessions");
    }

获得session文件的方法：

    protected File file() {

        if ((pathname == null) || (pathname.length() == 0))
            return (null);
        File file = new File(pathname);
        if (!file.isAbsolute()) {
            if (container instanceof Context) {
                ServletContext servletContext =
                    ((Context) container).getServletContext();
                File tempdir = (File)
                    servletContext.getAttribute(Globals.WORK_DIR_ATTR);
                if (tempdir != null)
                    file = new File(tempdir, pathname);
            }
        }
//        if (!file.isAbsolute())
//            return (null);
        return (file);

    }