tomcat(9)Session管理

public void run() { //org.apache.catalina.session.PersistentManagerBase.run()
    while(!threadDone) {
        threadSleep();
        processExpires(); // 检查Session对象是否过期.
        processPersistenceChecks();
    }    
}
public void processPersistenceChecks(){ // org.apache.catalina.session.PersistentManagerBase.processPersistenceChecks()
    processMaxIdleSwaps(); // highlight line.(下面我们只以processMaxIdleSwaps方法为例进行调用过程的分析，其他两个方法类似)
    processMaxActiveSwaps(); // highlight line.
    processMaxIdleBackups(); // highlight line.
}

/**
     * Swap idle sessions out to Store if they are idle too long.若session空闲太久则换出
     */
    protected void processMaxIdleSwaps() {
        if (!isStarted() || maxIdleSwap < 0)
            return;

        Session sessions[] = findSessions();
        long timeNow = System.currentTimeMillis();

        // Swap out all sessions idle longer than maxIdleSwap
        // FIXME: What's preventing us from mangling a session during
        // a request?
        if (maxIdleSwap >= 0) {
            for (int i = 0; i < sessions.length; i++) {
                StandardSession session = (StandardSession) sessions[i];
                if (!session.isValid())
                    continue;
                long lastAccessed = ((StandardSession)session).getLastUsedTime();
                int timeIdle = // Truncate, do not round up
                    (int) ((timeNow - lastAccessed) / 1000L);
                if (timeIdle > maxIdleSwap && timeIdle > minIdleSwap) {
                    if (debug > 1)
                        log(sm.getString
                            ("persistentManager.swapMaxIdle",
                             session.getId(), new Integer(timeIdle)));
                    try {
                        swapOut(session); // highlight line.
                    } catch (IOException e) {
                        ;   // This is logged in writeSession()
                    }
                }
            }
        }
    }

protected void swapOut(Session session) throws IOException { //换出操作
        if (store == null ||
                !session.isValid() ||
                isSessionStale(session, System.currentTimeMillis()))
            return;

        ((StandardSession)session).passivate();
        writeSession(session); // highlight line.
        super.remove(session);
        session.recycle();
    }

protected void writeSession(Session session) throws IOException {

        if (store == null ||
                !session.isValid() ||
                isSessionStale(session, System.currentTimeMillis()))
            return;

        try {
            store.save(session); //highlight line.
            sessionSwapIgnore.remove(session.getId());
        } catch (IOException e) {
            log(sm.getString
                ("persistentManager.serializeError", session.getId(), e));
            throw e;
        }
    }

public Session findSession(String id) throws IOException { //org.apache.catalina.session.PersistentManagerBase.findSession()
        Session session = super.findSession(id);
        if (session != null)
            return (session);

        // See if the Session is in the Store
        session = swapIn(id); // highlight line.
        return (session);
    }

protected Session swapIn(String id) throws IOException { // the same as the above.
        if (store == null)
            return null;

        if (sessionSwapIgnore.contains(id)) {
            return null;
        }

        Session session = null;
        try {
            session = store.load(id); // highlight line.
        } catch (ClassNotFoundException e) {
            log(sm.getString("persistentManager.deserializeError", id, e));
            throw new IllegalStateException
                (sm.getString("persistentManager.deserializeError", id, e));
        }

        if (session == null) {
            sessionSwapIgnore.put(id,id);
            return (null);
        }

        if (!session.isValid()
                || isSessionStale(session, System.currentTimeMillis())) {
            log("session swapped in is invalid or expired");
            session.expire(); // highlight line.
            store.remove(id); // highlight line.
            sessionSwapIgnore.put(id,id);
            return (null);
        }

        if(debug > 2)
            log(sm.getString("persistentManager.swapIn", id));

        session.setManager(this);
        // To make sure the listener knows about it.
        ((StandardSession)session).tellNew();
        add(session);
        ((StandardSession)session).activate();
        return (session);
    }

public final class PersistentManager extends PersistentManagerBase {  //org.apache.catalina.session.PersistentManager 
    private static final String info = "PersistentManager/1.0";   
    protected static String name = "PersistentManager";  
    public String getInfo() {
        return (this.info);
    }  
    public String getName() {
        return (name);
    }
 }

 public Session createSession() {
        Session session = super.createSession(); // step1.
        ObjectOutputStream oos = null;
        ByteArrayOutputStream bos = null;
        ByteArrayInputStream bis = null;
        try {
            bos = new ByteArrayOutputStream();
            oos = new ObjectOutputStream(new BufferedOutputStream(bos));
            ((StandardSession)session).writeObjectData(oos);
            oos.close();
            byte[] obs = bos.toByteArray();
            clusterSender.send(obs); // step2.
            if(debug > 0)
                log("Replicating Session: "+session.getId());
        } catch (IOException e) {
            log("An error occurred when replicating Session: "+session.getId());
        }
        return (session);
    }

public void run() { // org.apache.catalina.session.DistributedManager.run()
        // Loop until the termination semaphore is set
        while (!threadDone) {
            threadSleep();
            processClusterReceiver(); // 以该方法为例进行说明.
            processExpires();
            processPersistenceChecks();
        }
    }

/**
     * Called from our background thread to process new received Sessions
     *
     */
    public void processClusterReceiver() { //org.apache.catalina.session.DistributedManager.processClusterReceiver()
        Object[] objs = clusterReceiver.getObjects();
        StandardSession _session = null;
        ByteArrayInputStream bis = null;
        Loader loader = null;
        ClassLoader classLoader = null;
        ObjectInputStream ois = null;
        byte[] buf = new byte[5000];
        ReplicationWrapper repObj = null;

        for(int i=0; i < objs.length;i++) {
            try {
                bis = new ByteArrayInputStream(buf);
                repObj = (ReplicationWrapper)objs[i];
                buf = repObj.getDataStream();
                bis = new ByteArrayInputStream(buf, 0, buf.length);

                if (container != null)
                    loader = container.getLoader();

                if (loader != null)
                    classLoader = loader.getClassLoader();

                if (classLoader != null)
                    ois = new CustomObjectInputStream(bis,
                                                      classLoader);
                else
                    ois = new ObjectInputStream(bis);

                _session = (StandardSession) super.createSession();
                _session.readObjectData(ois);
                _session.setManager(this);

                if (debug > 0)
                    log("Loading replicated session: "+_session.getId());
            } catch (IOException e) {
                log("Error occurred when trying to read replicated session: "+
                    e.toString());
            } catch (ClassNotFoundException e) {
                log("Error occurred when trying to read replicated session: "+
                    e.toString());
            } finally {
                if (ois != null) {
                    try {
                        ois.close();
                        bis = null;
                    } catch (IOException e) {
                        ;
                    }
                }
            }
        }
    }

public interface Store { // org.apache.catalina.Store
    public String getInfo(); 
    public Manager getManager(); 
    public void setManager(Manager manager); 
    public int getSize() throws IOException; 
    public void addPropertyChangeListener(PropertyChangeListener listener); 
    public String[] keys() throws IOException; 
    public Session load(String id) 
        throws ClassNotFoundException, IOException;
    public void remove(String id) throws IOException; 
    public void clear() throws IOException; 
    public void removePropertyChangeListener(PropertyChangeListener listener); 
    public void save(Session session) throws IOException; 
} 

 public void run() { // org.apache.catalina.session.StoreBase.run()
        // Loop until the termination semaphore is set
        while (!threadDone) {
            threadSleep();
            processExpires();
        }
    }

public static void main(String[] args) {
    //invoke: http://localhost:8080/myApp/Session
    System.setProperty("catalina.base", System.getProperty("user.dir"));
    Connector connector = new HttpConnector();
    Wrapper wrapper1 = new SimpleWrapper();
    wrapper1.setName("Session");
    wrapper1.setServletClass("SessionServlet");

    Context context = new StandardContext();
    // StandardContext's start method adds a default mapper
    context.setPath("/myApp");
    context.setDocBase("myApp");

    context.addChild(wrapper1);

    // context.addServletMapping(pattern, name);
    // note that we must use /myApp/Session, not just /Session
    // because the /myApp section must be the same as the path, so the cookie will
    // be sent back.
    context.addServletMapping("/myApp/Session", "Session");
    // add ContextConfig. This listener is important because it configures
    // StandardContext (sets configured to true), otherwise StandardContext
    // won't start
    LifecycleListener listener = new SimpleContextConfig();
    ((Lifecycle) context).addLifecycleListener(listener);

    // here is our loader
    Loader loader = new WebappLoader();
    // associate the loader with the Context
    context.setLoader(loader);

    connector.setContainer(context);

    // add a Manager
    Manager manager = new StandardManager(); // highlight line.
    context.setManager(manager); // highlight line.

    try {
      connector.initialize();
      ((Lifecycle) connector).start();

      ((Lifecycle) context).start();

      // make the application wait until we press a key.
      System.in.read();
      ((Lifecycle) context).stop();
    }
    catch (Exception e) {
      e.printStackTrace();
    }
  }
}

 public void invoke(Request request, Response response, ValveContext valveContext)
    throws IOException, ServletException {
    SimpleWrapper wrapper = (SimpleWrapper) getContainer();
    ServletRequest sreq = request.getRequest();
    ServletResponse sres = response.getResponse();
    Servlet servlet = null;
    HttpServletRequest hreq = null;
    if (sreq instanceof HttpServletRequest)
      hreq = (HttpServletRequest) sreq;
    HttpServletResponse hres = null;
    if (sres instanceof HttpServletResponse)
      hres = (HttpServletResponse) sres;

    //-- new addition -----------------------------------
    Context context = (Context) wrapper.getParent(); // highlight line.
    request.setContext(context); // highlight line.
    //-------------------------------------
    // Allocate a servlet instance to process this request
    try {
      servlet = wrapper.allocate();
      if (hres!=null && hreq!=null) {
        servlet.service(hreq, hres);
      }
      else {
        servlet.service(sreq, sres);
      }
    }
    catch (ServletException e) {
    }
  }

Manager manager = null;
if(contect != null)
    manager = context.getManager();