session自己定义存储。怎样更好地进行session共享；
读tomcat源代码，org.apache.catalina.session.FileStore可知
一、详见：
方法1 public void save(Session session)
try {
((StandardSession)session).writeObjectData(oos);
} finally {
oos.close();
}
方法2 public Session load(String id)
ois = new ObjectInputStream(bis);
StandardSession session = (StandardSession) manager.createEmptySession();
session.readObjectData(ois);
session.setManager(manager);
return (session);
二、在conf/context.xml文件设置：这个是针对全部的项目了。也能够针对详细项目来配置在server.xml中。
打开context.xml，在<Context>节点下加入例如以下<Manager>节点：
<Manager className="org.apache.catalina.session.PersistentManager" >
debug=0
saveOnRestart="true"
maxActiveSession="-1"
minIdleSwap="-1"
maxIdleSwap="-1"
maxIdleBackup="-1"
<Store className="org.apache.catalina.session.FileStore" directory="../session" />
//这里代表的是文件持久化.也能够自己实现Store
</Manager>
三、源代码见下文
* Licensed to the Apache Software Foundation (ASF) under one or more
package org.apache.catalina.session;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.ArrayList;
import javax.servlet.ServletContext;
import org.apache.catalina.Container;
import org.apache.catalina.Context;
import org.apache.catalina.Loader;
import org.apache.catalina.Session;
import org.apache.catalina.util.CustomObjectInputStream;
/**
* Concrete implementation of the <b>Store</b> interface that utilizes
* a file per saved Session in a configured directory. Sessions that are
* saved are still subject to being expired based on inactivity.
*
* @author Craig R. McClanahan
*/
public final class FileStore extends StoreBase {
// ----------------------------------------------------- Constants
/**
* The extension to use for serialized session filenames.
*/
private static final String FILE_EXT = ".session";
// ----------------------------------------------------- Instance Variables
/**
* The pathname of the directory in which Sessions are stored.
* This may be an absolute pathname, or a relative path that is
* resolved against the temporary work directory for this application.
*/
private String directory = ".";
/**
* A File representing the directory in which Sessions are stored.
*/
private File directoryFile = null;
/**
* The descriptive information about this implementation.
*/
private static final String info = "FileStore/1.0";
/**
* Name to register for this Store, used for logging.
*/
private static final String storeName = "fileStore";
/**
* Name to register for the background thread.
*/
private static final String threadName = "FileStore";
// ------------------------------------------------------------- Properties
/**
* Return the directory path for this Store.
*/
public String getDirectory() {
return (directory);
}
/**
* Set the directory path for this Store.
*
* @param path The new directory path
*/
public void setDirectory(String path) {
String oldDirectory = this.directory;
this.directory = path;
this.directoryFile = null;
support.firePropertyChange("directory", oldDirectory,
this.directory);
}
/**
* Return descriptive information about this Store implementation and
* the corresponding version number, in the format
* <code><description>/<version></code>.
*/
@Override
public String getInfo() {
return (info);
}
/**
* Return the thread name for this Store.
*/
public String getThreadName() {
return(threadName);
}
/**
* Return the name for this Store, used for logging.
*/
@Override
public String getStoreName() {
return(storeName);
}
/**
* Return the number of Sessions present in this Store.
*
* @exception IOException if an input/output error occurs
*/
@Override
public int getSize() throws IOException {
// Acquire the list of files in our storage directory
File file = directory();
if (file == null) {
return (0);
}
String files[] = file.list();
// Figure out which files are sessions
int keycount = 0;
for (int i = 0; i < files.length; i++) {
if (files[i].endsWith(FILE_EXT)) {
keycount++;
}
}
return (keycount);
}
// --------------------------------------------------------- Public Methods
/**
* Remove all of the Sessions in this Store.
*
* @exception IOException if an input/output error occurs
*/
@Override
public void clear()
throws IOException {
String[] keys = keys();
for (int i = 0; i < keys.length; i++) {
remove(keys[i]);
}
}
/**
* Return an array containing the session identifiers of all Sessions
* currently saved in this Store. If there are no such Sessions, a
* zero-length array is returned.
*
* @exception IOException if an input/output error occurred
*/
@Override
public String[] keys() throws IOException {
// Acquire the list of files in our storage directory
File file = directory();
if (file == null) {
return (new String[0]);
}
String files[] = file.list();
// Bugzilla 32130
if((files == null) || (files.length < 1)) {
return (new String[0]);
}
// Build and return the list of session identifiers
ArrayList<String> list = new ArrayList<String>();
int n = FILE_EXT.length();
for (int i = 0; i < files.length; i++) {
if (files[i].endsWith(FILE_EXT)) {
list.add(files[i].substring(0, files[i].length() - n));
}
}
return list.toArray(new String[list.size()]);
}
/**
* Load and return the Session associated with the specified session
* identifier from this Store, without removing it. If there is no
* such stored Session, return <code>null</code>.
*
* @param id Session identifier of the session to load
*
* @exception ClassNotFoundException if a deserialization error occurs
* @exception IOException if an input/output error occurs
*/
@Override
public Session load(String id)
throws ClassNotFoundException, IOException {
// Open an input stream to the specified pathname, if any
File file = file(id);
if (file == null) {
return (null);
}
if (! file.exists()) {
return (null);
}
if (manager.getContainer().getLogger().isDebugEnabled()) {
manager.getContainer().getLogger().debug(sm.getString(getStoreName()+".loading",
id, file.getAbsolutePath()));
}
FileInputStream fis = null;
BufferedInputStream bis = null;
ObjectInputStream ois = null;
Loader loader = null;
ClassLoader classLoader = null;
ClassLoader oldThreadContextCL = Thread.currentThread().getContextClassLoader();
try {
fis = new FileInputStream(file.getAbsolutePath());
bis = new BufferedInputStream(fis);
Container container = manager.getContainer();
if (container != null)
loader = container.getLoader();
if (loader != null)
classLoader = loader.getClassLoader();
if (classLoader != null) {
Thread.currentThread().setContextClassLoader(classLoader);
ois = new CustomObjectInputStream(bis, classLoader);
} else {
ois = new ObjectInputStream(bis);
}
StandardSession session =
(StandardSession) manager.createEmptySession();
session.readObjectData(ois);
session.setManager(manager);
return (session);
} catch (FileNotFoundException e) {
if (manager.getContainer().getLogger().isDebugEnabled())
manager.getContainer().getLogger().debug("No persisted data file found");
return (null);
} catch (IOException e) {
if (bis != null) {
try {
bis.close();
} catch (IOException f) {
// Ignore
}
}
if (fis != null) {
try {
fis.close();
} catch (IOException f) {
// Ignore
}
}
throw e;
} finally {
if (ois != null) {
// Close the input stream
try {
ois.close();
} catch (IOException f) {
// Ignore
}
}
Thread.currentThread().setContextClassLoader(oldThreadContextCL);
}
}
/**
* Remove the Session with the specified session identifier from
* this Store, if present. If no such Session is present, this method
* takes no action.
*
* @param id Session identifier of the Session to be removed
*
* @exception IOException if an input/output error occurs
*/
@Override
public void remove(String id) throws IOException {
File file = file(id);
if (file == null) {
return;
}
if (manager.getContainer().getLogger().isDebugEnabled()) {
manager.getContainer().getLogger().debug(sm.getString(getStoreName()+".removing",
id, file.getAbsolutePath()));
}
file.delete();
}
/**
* Save the specified Session into this Store. Any previously saved
* information for the associated session identifier is replaced.
*
* @param session Session to be saved
*
* @exception IOException if an input/output error occurs
*/
@Override
public void save(Session session) throws IOException {
// Open an output stream to the specified pathname, if any
File file = file(session.getIdInternal());
if (file == null) {
return;
}
if (manager.getContainer().getLogger().isDebugEnabled()) {
manager.getContainer().getLogger().debug(sm.getString(getStoreName()+".saving",
session.getIdInternal(), file.getAbsolutePath()));
}
FileOutputStream fos = null;
ObjectOutputStream oos = null;
try {
fos = new FileOutputStream(file.getAbsolutePath());
oos = new ObjectOutputStream(new BufferedOutputStream(fos));
} catch (IOException e) {
if (fos != null) {
try {
fos.close();
} catch (IOException f) {
// Ignore
}
}
throw e;
}
try {
((StandardSession)session).writeObjectData(oos);
} finally {
oos.close();
}
}
// -------------------------------------------------------- Private Methods
/**
* Return a File object representing the pathname to our
* session persistence directory, if any. The directory will be
* created if it does not already exist.
*/
private File directory() throws IOException {
if (this.directory == null) {
return (null);
}
if (this.directoryFile != null) {
// NOTE: Race condition is harmless, so do not synchronize
return (this.directoryFile);
}
File file = new File(this.directory);
if (!file.isAbsolute()) {
Container container = manager.getContainer();
if (container instanceof Context) {
ServletContext servletContext =
((Context) container).getServletContext();
File work = (File)
servletContext.getAttribute(ServletContext.TEMPDIR);
file = new File(work, this.directory);
} else {
throw new IllegalArgumentException
("Parent Container is not a Context");
}
}
if (!file.exists() || !file.isDirectory()) {
if (!file.delete() && file.exists()) {
throw new IOException(
sm.getString("fileStore.deleteFailed", file));
}
if (!file.mkdirs() && !file.isDirectory()) {
throw new IOException(
sm.getString("fileStore.createFailed", file));
}
}
this.directoryFile = file;
return (file);
}
/**
* Return a File object representing the pathname to our
* session persistence file, if any.
*
* @param id The ID of the Session to be retrieved. This is
* used in the file naming.
*/
private File file(String id) throws IOException {
if (this.directory == null) {
return (null);
}
String filename = id + FILE_EXT;
File file = new File(directory(), filename);
return (file);
}
}