| # Apache Tomcat 7 Version 7.0.81, Aug 11 2017 |

Links Docs Home Config Ref. Home FAQ User Comments Top Level Elements Server Service Executors Executor Connectors HTTP AJP Containers Context Engine Host Cluster Nested Components Global Resources JarScanner Listeners Loader Manager Realm Resources SessionIdGenerator Valve Cluster Elements Cluster Manager Channel Channel/Membership Channel/Sender Channel/Receiver Channel/Interceptor Valve Deployer ClusterListener web.xml Filter Other System properties | # The SessionIdGenerator Component
Table of Contents
Introduction Attributes Common Attributes Standard Implementation
Introduction
The SessionIdGenerator element represents the session id generator that will be used to create session ids used by web application HTTP sessions. A SessionIdGenerator element MAY be nested inside a Manager component. If it is not included, a default SessionIdGenerator configuration will be created automatically, which is sufficient for most requirements, — see Standard SessionIdGenerator Implementation below for the details of this configuration.
Attributes
> Common Attributes
> > All implementations of SessionIdGenerator support the following attributes:
> > Attribute | Description
> > --- | ---
> > `className` | Java class name of the implementation to use. This class must implement the `org.apache.catalina.SessionIdGenerator` interface. If not specified, the standard value (defined below) will be used.
> > `jvmRoute` | A routing identifier for this Tomcat instance. It will be added to the session id to allow for stateless stickyness routing by load balancers. The details on how the `jvmRoute` will be included in the id are implementation dependent. See Standard Implementation for the default behavior. NOTE - The value for this property is inherited automatically from the `jvmRoute` attribute of the Engine element.
> > `sessionIdLength` | The length of session ids created by this SessionIdGenerator. The details on how the `sessionIdLength` influences the session id length are implementation dependent. See Standard Implementation for the default behavior.
> Standard Implementation
> > Tomcat provides a standard implementations of SessionIdGenerator for use. ### Standard SessionIdGenerator Implementation The standard implementation of SessionIdGenerator is org.apache.catalina.util.StandardSessionIdGenerator. It supports the following attributes:
> > Attribute | Description
> > --- | ---
> > `jvmRoute` | A routing identifier for this Tomcat instance. It will be added to the end of the session id separated by a ".".
> > `sessionIdLength` | The length of session ids created by this SessionIdGenerator. More precisely the session id length is twice the value of `sessionIdLength` plus the length of the trailing `jvmRoute` if given. The factor 2 is because the session id is constructed using `sessionIdLength` random bytes, each byte being encoded in two hex characters in the actual id. The default value is 16.
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