Geoserver learning note (iii): Introduction to the geoserver Architecture

Su Weimin http://www.gisdev.cn/http://blog.csdn.net/suen/ Date:

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The features of geoserver (geoserver learning notes (I): geoserver overview, http://blog.csdn.net/suen/archive/2009/10/25/4726204.aspx), and how to download and Load Code in eclipse (II ): code download and load in eclipse, http://blog.csdn.net/suen/archive/2009/10/25/4726733.aspx), then you have to start the formal analysis.

The beginning of the analysis will generally be explained in general, but because it is a learning note, I am learning and writing, and I still cannot grasp the architecture well. Therefore, I can only say this question, I simply reprinted other technical articles and explained my understanding. let me talk about it later. please forgive me. (somehow, Google's pinyin cannot call Chinese characters, and only English characters can be used)

1 geoserver engineering and design

(This part of Content reproduced, reproduced from the http://geoserver.sourceforge.net/documentation/javadocs/index.html)

The geoserver project-the open Internet gateway for geographic data

Packages
Org. vfny. geoserver	Contains all interface Servlets, one for each WFS response.
Org. vfny. geoserver. action	Control of the geoserver application (struts actions ).
Org. vfny. geoserver. action. data	Contains actions for processing the geoserver data model.
Org. vfny. geoserver. action. global
Org. vfny. geoserver. action. validation
Org. vfny. geoserver. action. wfs	Contains actions for processing the geoserver Web Feature server.
Org. vfny. geoserver. action. wms	Contains actions for processing the geoserver Web Map Server.
Org. vfny. geoserver. config	Configuration model being edited.
Org. vfny. geoserver. config. validation	Validation model being edited.
Org. vfny. geoserver. form	Java Beans used to represent input screens (STRUTS Form Beans ).
Org. vfny. geoserver. form. data	Contains Form Beans describing the GeoServer Data Model.
Org. vfny. geoserver. form. global
Org. vfny. geoserver. Form. Validation
Org. vfny. geoserver. Form. WFS	Contains Web Feature Server Form Beans.
Org. vfny. geoserver. Form. WMS	Contains Web Map Server Form Beans.
Org. vfny. geoserver. Global	Maintains the GeoServer applicaiton state (This is the Application ).
Org. vfny. geoserver. Global. DTO	Maintains the Data Transfer Objects used to set up GeoServer.
Org. vfny. geoserver. Global. xml	Offers XML based persistence to the GeoServer application.
Org. vfny. geoserver. servlets	Provides Servlets Framework used by GeoServer.
Org. vfny. geoserver. util	Manages all of the top-level responses.
Org. vfny. geoserver. util. Requests	Handles all of the request processing for GeoServer.
Org. vfny. geoserver. util. Requests. Readers	Client request processing into GeoServer Request objects.
Org. vfny. geoserver. WFS
Org. vfny. geoserver. WFS. Requests	Handles all of the WFS request processing for GeoServer.
Org. vfny. geoserver. WFS. Requests. Readers	WFS Client request processing into Request objects for the GeoServer framework.
Org. vfny. geoserver. WFS. Responses	Manages all of the top-level WFS responses.
Org. vfny. geoserver. WFS. servlets	Provides Servlets for the GeoServer Web Feature Server implementation.
Org. vfny. geoserver. WMS
Org. vfny. geoserver. WMS. Requests	Handles all of the request processing for the WMS interfaces.
Org. vfny. geoserver. WMS. Responses	Manages all of the top-level WMS responses.
Org. vfny. geoserver. WMS. Responses. featureinfo
Org. vfny. geoserver. WMS. Responses. helpers
Org. vfny. geoserver. wms. responses. map	Manages all of the WMS Map responses.
Org.vfny.geoserver.wms.responses.map.gif
Org. vfny. geoserver. wms. responses. map. kml
Org.vfny.geoserver.wms.responses.map.png
Org. vfny. geoserver. wms. responses. map. svg
Org. vfny. geoserver. wms. servlets	Provides Servlets for the GeoServer Web Map Server implementation.
Org. vfny. geoserver. zserver	Provides a ZServer Catalog Service for GeoServer.

The geoserver project-the open Internet gateway for geographic data

The geoserver Project is a Java (J2EE) implementation:

• The OpenGIS Consortium's Web Feature server specification. With full transactional support!
• The OpenGIS Consortium's Web Map Server specification.
• Zserver

GeoServer is free software, available under the GPL 2.0 license.

Users who wocould like to access and modify their geographic data over the Internet using flexible, industry-approved standards shocould take a look at GeoServer.

Geoserver Design

GeoServer is constructed using a Layered Design as outlined in the dimo-below. There are two Layer systems in use-the classic J2EE Servlet/Handler/Request/Response and the STRUTS Framework.

Geoserver layer digoal

Use of geotools2

As seen in the above Layer dimo-geoserver makes use of the wonderful GeoTools2 library to provide data access. geoServer maintains its own geotools. jar available in the lib directory. this jar is often more recent then the latest GeoTools public beta.

Many GeoServer classes implement GeoTools2 interfaces inorder to facilitate reuse and intergration with subsystems such as validation.

2 geoserver Architecture

(This part of Content reproduced, reproduced from the http://geoserver.org/display/GEOSDOC/1+GeoServer+Architecture)

The following dimo-provides an overview of the geoserver architecture. The geoserver application is comprised of a seriesModules. Geoserver modules can be combined with ourMaven 2Build sytem to form a deployable war.

At runtime a module can make use of spring to obtain classes providing services from other modules. This ability to "plug-in" additional functionality forms the basis for geoserversExtension mechanic. This mechanism is used to provide additional OGC Web Services (by the WFS and WMS modules) and to implement support for different WMS image encodings.

The core geoserver modules serve as a useful example of how new services can be added. You can reviewWebModule for an example of packaging modules into a deployable war.

Note:

Based on geotools, geoserver implements the logic of the application layer and Web Container layer. The main projects include data, main, validation, web, WMS, and WFS. Based on the Spring framework, the system has good scalability and can add new services. (Google Pinyin is okay again, but it is still not stable)