The first problem is: If i put reportExport. After deploying the webapp the start is fine. The second problem is the reportExport. So something is wrong with my setup: i want the system administrator to setup the data source specific for my application. I like the idea with a separate file per web app but the exception on first setup and the deletion on undeploying are bad. On the other hand it is probably good to setup data source in server. OK, the easiest way: - in the server. So inside you.
If you want you can even rename it in the context. But I would recommend to keep different names in each app so you directly see what you are accessing personal taste. The main problem with that solution is that another web app can reference any of the global resources in its context. If it is, you don't manually put. However, only the classes needed for connection pooling have been included, and the packages have been renamed to avoid interfering with applications.
See the DBCP 2 documentation for a complete list of configuration parameters. A database connection pool creates and manages a pool of connections to a database. Recycling and reusing already existing connections to a database is more efficient than opening a new connection.
There is one problem with connection pooling. A web application has to explicitly close ResultSet's, Statement's, and Connection's. Failure of a web application to close these resources can result in them never being available again for reuse, a database connection pool "leak".
This can eventually result in your web application database connections failing if there are no more available connections. There is a solution to this problem.
Not only can it recover them, but also generate a stack trace for the code which opened these resources and never closed them. The default for both of these attributes is false. Note that removeAbandonedOnMaintenance has no effect unless pool maintenance is enabled by setting timeBetweenEvictionRunsMillis to a positive value.
See the DBCP 2 documentation for full documentation on these attributes. Use the removeAbandonedTimeout attribute to set the number of seconds a database connection has been idle before it is considered abandoned.
The logAbandoned attribute can be set to true if you want DBCP 2 to log a stack trace of the code which abandoned the database connection resources. Create a new test user, a new database and a single test table. Your MySQL user must have a password assigned.
The driver will fail if you try to connect with an empty password. Once you have JSTL, copy jstl. Therefore classes Since jarfiles are zipfiles, there is no need to unzip and jar these files - a simple rename will suffice. For Oracle 9i onwards you should use oracle.
OracleDriver rather than oracle. OracleDriver as Oracle have stated that oracle. OracleDriver is deprecated and support for this driver class will be discontinued in the next major release. In a similar manner to the mysql config above, you will need to define your Datasource in your Context.
Here we define a Datasource called myoracle using the thin driver to connect as user scott, password tiger to the sid called mysid. Note: with the thin driver this sid is not the same as the tnsname. The schema used will be the default schema for the user scott. You should ensure that you respect the element ordering defined by the DTD when you create you applications web.
You can use the same example application as above assuming you create the required DB instance, tables etc.
This has to be done regardless of which configuration step you take next. You have two choices here: define a datasource that is shared across all Tomcat applications, or define a datasource specifically for one application. Use this option if you wish to define a datasource that is shared across multiple Tomcat applications, or if you just prefer defining your datasource in this file.
This author has not had success here, although others have reported so. Clarification would be appreciated here. Use this option if you wish to define a datasource specific to your application, not visible to other Tomcat applications. This method is less invasive to your Tomcat installation.
Create a resource definition for your Context. The Context element should look something like the following. These solutions either utilise a single connection to the database not recommended for anything other than testing!
In order to use OCI driver, you should have an Oracle client installed. You should have installed Oracle8i 8. After renaming classes You may also have to remove the javax. Ensure that you have the ocijdbc8. You should next create a simple test servlet or jsp that has these critical lines :. The Oracle documentation says : "Cause: The login connect string contains an invalid driver designator.
Action: Correct the string and re-submit. Here are some common problems encountered with a web application which uses a database and tips for how to solve them. Tomcat runs within a JVM. Introduction web. Global configuration. Using resources. Tomcat Standard Resource Factories. Generic JavaBean Resources.
Introduction This resource factory can be used to create objects of any Java class that conforms to standard JavaBeans naming conventions i. The steps required to use this facility are described below. MyBean , which looks like this: package com. Assume our bean looks like this: package com. UserDatabase Resources. Introduction UserDatabase resources are typically configured as global resources for use by a UserDatabase realm.
Configure the Realm Configure a UserDatabase Realm to use this resource as described in the Realm configuration documentation.
JavaMail Sessions. Introduction In many web applications, sending electronic mail messages is a required part of the system's functionality. The steps required for this are outlined below. Introduction Many web applications need to access a database via a JDBC driver, to support the functionality required by that application.
DataSource API. For backwards compatibility, the property driverName is also recognized. Default: 0 maxActive - The maximum number of connections that can be allocated from this pool at the same time. Default: 8 minIdle - The minimum number of connections that will sit idle in this pool at the same time. Default: 0 maxIdle - The maximum number of connections that can sit idle in this pool at the same time. Default: 8 maxWait - The maximum number of milliseconds that the pool will wait when there are no available connections for a connection to be returned before throwing an exception.
Default: -1 infinite Some additional properties handle connection validation: validationQuery - SQL query that can be used by the pool to validate connections before they are returned to the application.
Default: -1 infinite testOnBorrow - true or false: whether a connection should be validated using the validation query each time it is borrowed from the pool. Default: true testOnReturn - true or false: whether a connection should be validated using the validation query each time it is returned to the pool. Default: false The optional evictor thread is responsible for shrinking the pool by removing any connections which are idle for a long time.
The evictor is disabled by default and can be configured using the following properties: timeBetweenEvictionRunsMillis - The number of milliseconds between consecutive runs of the evictor.
Default: -1 disabled numTestsPerEvictionRun - The number of connections that will be checked for idleness by the evictor during each run of the evictor. Default: 3 minEvictableIdleTimeMillis - The idle time in milliseconds after which a connection can be removed from the pool by the evictor.
Default: false Another optional feature is the removal of abandoned connections. The abandoning feature is disabled by default and can be configured using the following properties: removeAbandoned - true or false: whether to remove abandoned connections from the pool. Default: false removeAbandonedTimeout - The number of seconds after which a borrowed connection is assumed to be abandoned.
Default: logAbandoned - true or false: whether to log stack traces for application code which abandoned a statement or connection. This adds serious overhead. Default: false Finally there are various properties that allow further fine tuning of the pool behaviour: defaultAutoCommit - true or false: default auto-commit state of the connections created by this pool.
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