bboss.org.apache.velocity.runtime.resource.loader

类 DataSourceResourceLoader

java.lang.Object

bboss.org.apache.velocity.runtime.resource.loader.ResourceLoader

bboss.org.apache.velocity.runtime.resource.loader.DataSourceResourceLoader

public class DataSourceResourceLoader
extends ResourceLoader

This is a simple template file loader that loads templates from a DataSource instead of plain files.

It can be configured with a datasource name, a table name, id column (name), content column (the template body) and a datetime column (for last modification info).

Example configuration snippet for velocity.properties:

resource.loader = file, ds

ds.resource.loader.public.name = DataSource
ds.resource.loader.description = Velocity DataSource Resource Loader
ds.resource.loader.class = bboss.org.apache.velocity.runtime.resource.loader.DataSourceResourceLoader
ds.resource.loader.resource.datasource = java:comp/env/jdbc/Velocity
ds.resource.loader.resource.table = tb_velocity_template
ds.resource.loader.resource.keycolumn = id_template
ds.resource.loader.resource.templatecolumn = template_definition
ds.resource.loader.resource.timestampcolumn = template_timestamp
ds.resource.loader.cache = false
ds.resource.loader.modificationCheckInterval = 60

Optionally, the developer can instantiate the DataSourceResourceLoader and set the DataSource via code in a manner similar to the following:

DataSourceResourceLoader ds = new DataSourceResourceLoader();
ds.setDataSource(DATASOURCE);
Velocity.setProperty("ds.resource.loader.instance",ds);

The property ds.resource.loader.class should be left out, otherwise all the other properties in velocity.properties would remain the same.

Example WEB-INF/web.xml:


Velocity template DataSource
jdbc/Velocity
javax.sql.DataSource
Container



and Tomcat 4 server.xml file:
[...]

[...]


driverClassName
org.hsql.jdbcDriver


driverName
jdbc:HypersonicSQL:database


user
database_username


password
database_password


[...]

[...]

Example sql script:
CREATE TABLE tb_velocity_template (
id_template varchar (40) NOT NULL ,
template_definition text (16) NOT NULL ,
template_timestamp datetime NOT NULL
)

从以下版本开始:

1.5

字段概要

从类继承的字段 bboss.org.apache.velocity.runtime.resource.loader.ResourceLoader

className, isCachingOn, log, modificationCheckInterval, rsvc

构造器概要

构造器

构造器和说明
DataSourceResourceLoader()

方法概要

限定符和类型	方法和说明
long	getLastModified(Resource resource) Get the last modified time of the InputStream source that was used to create the template.
java.io.InputStream	getResourceStream(java.lang.String name) Get an InputStream so that the Runtime can build a template with it.
void	init(org.apache.commons.collections.ExtendedProperties configuration) Initialize the template loader with a a resources class.
boolean	isSourceModified(Resource resource) Given a template, check to see if the source of InputStream has been modified.
void	setDataSource(javax.sql.DataSource dataSource) Set the DataSource used by this resource loader.

从类继承的方法 bboss.org.apache.velocity.runtime.resource.loader.ResourceLoader

commonInit, getClassName, getModificationCheckInterval, isCachingOn, resourceExists, setCachingOn, setModificationCheckInterval

从类继承的方法 java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

构造器详细资料

DataSourceResourceLoader

public DataSourceResourceLoader()

方法详细资料

init

public void init(org.apache.commons.collections.ExtendedProperties configuration)

从类复制的说明: ResourceLoader

Initialize the template loader with a a resources class.

指定者:

init 在类中 ResourceLoader

另请参阅:

ResourceLoader.init(org.apache.commons.collections.ExtendedProperties)

setDataSource

public void setDataSource(javax.sql.DataSource dataSource)

Set the DataSource used by this resource loader. Call this as an alternative to specifying the data source name via properties.

参数:

dataSource - The data source for this ResourceLoader.

isSourceModified

public boolean isSourceModified(Resource resource)

从类复制的说明: ResourceLoader

Given a template, check to see if the source of InputStream has been modified.

指定者:

isSourceModified 在类中 ResourceLoader

返回:

True if the resource has been modified.

另请参阅:

ResourceLoader.isSourceModified(bboss.org.apache.velocity.runtime.resource.Resource)

getLastModified

public long getLastModified(Resource resource)

从类复制的说明: ResourceLoader

Get the last modified time of the InputStream source that was used to create the template. We need the template here because we have to extract the name of the template in order to locate the InputStream source.

指定者:

getLastModified 在类中 ResourceLoader

返回:

Time in millis when the resource has been modified.

另请参阅:

ResourceLoader.getLastModified(bboss.org.apache.velocity.runtime.resource.Resource)

getResourceStream

public java.io.InputStream getResourceStream(java.lang.String name)
                                      throws ResourceNotFoundException

Get an InputStream so that the Runtime can build a template with it.

指定者:

getResourceStream 在类中 ResourceLoader

参数:

name - name of template

返回:

InputStream containing template

抛出:

ResourceNotFoundException