Transcript Building an application … with Struts!

Struts Petstore
Struts University Series
Abstract
Struts has always shipped with a simple
example application. But for many
teams, MailReader is a bit too simple.
Struts Petstore is a full-featured,
production-grade Struts application
inspired by the infamous Java Pet
Store. Struts Petstore uses a
professional architecture that hooks up
to Apache iBATIS for data access. Let's
have a look ...
Struts PetStore
A little background
Sun creates J2EE Pet Store
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Demonstrates patterns
Microsoft creates .NET Pet Shop
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Demonstrates performance
Clinton Begin creates JPetStore
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Demonstrates iBATIS
iBATIS and Struts
iBATIS
Data mapping framework for SQL
 Compares to Hibernate and OJB

Struts
Web application framework
 Compares to WebWork and Tapestry

Clinton Begin
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Inventor of iBATIS and author of JPetStore
The Purpose of JPetStore
Clinton Begin wrote JPetstore to show
Java is easy
 Java is low cost
 Java is highly productive
 Java enables choice
 Java enables change

The Purpose of JPetStore
Clinton Begin wrote JPetstore to show
Java is easy
 Java is low cost
 Java is highly productive
 Java enables choice
 Java enables change
 iBATIS is cool

Advantages without Tradeoffs
JPetStore uses superior design and
architecture
Clearly defined application layers
 Uses known best practices and patterns
 Avoids known worst practices

No stored procedures
 No SQL embedded in Java code
 No HTML in the database
 No generated code

Presentation
Model View Controller Pattern
Well know and proven (GOF)
 Simple and maintainable

Apache Struts
Freely available, open source
 Based on JavaBeans
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Domain
JavaBeans



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Components with properties and behavior
Plug into presentation and persistence layers
Compatible with many frameworks
GUI tools available (IDEs, et cetera)
Logic Classes

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None/Verb separation
More maintainable than prior versions
Persistence
Data Access Objects
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“Pluggable” persistance components
Proven abstract factory pattern (GoF)
Improves maintainability and flexibility
SQL Maps
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Reduces/eliminates repetive JDBC code
Improves performance with caching
Portable across many databases
Based on JavaBeans
Link to a category query
JavaServer Page:
<html:link
page="/shop/viewCategory.shtml?categoryId=DOGS">
Struts Config:
<action path="/shop/viewCategory"
type="com.ibatis.struts.BeanAction"
name="catalogBean" scope="session"
validate="false" >
<forward name="success"
path="/catalog/Category.jsp"/>
</action>
CatalogBean
public String viewCategory() {
if (categoryId != null) {
productList =
catalogService.getProductListByCategory(categoryId);
category =
catalogService.getCategory(categoryId);
}
return "success";
}
CatalogService
public PaginatedList getProductListByCategory(String
categoryId) {
return
queryForPaginatedList("getProductListByCategory",
categoryId, PAGE_SIZE);
}
public Category getCategory(String categoryId) {
return (Category) queryForObject("getCategory",
categoryId);
}
SqlMaps
<select id="getCategoryList"
resultMap="categoryResult">
select CATID, NAME, DESCN from CATEGORY
</select>
<select id="getCategory"
resultMap="categoryResult"
parameterClass="string">
select CATID, NAME, DESCN from CATEGORY where
CATID = #value#
</select>
ResultMap
<resultMap id="categoryResult"
class="category">
<result property="categoryId"
column="CATID"/>
<result property="name"
column="NAME"/>
<result property="description"
column="DESCN"/>
</resultMap>
Cache Model
<cacheModel
id="oneDayCategory"
type="LRU">
<flushInterval hours="24"/>
</cacheModel>
Cache Model
<cacheModel
id="oneDayCategory"
type="LRU">
<flushInterval hours="24"/>
<flushOnExecute
statement="insertCategory"/>
</cacheModel>
Dynamic SQL
<select id="getCategoryList"
resultMap="categoryResult">
select CATID, NAME, DESCN from CATEGORY
</select>
<select id="getCategory"
resultMap="categoryResult"
parameterClass="string">
select CATID, NAME, DESCN from CATEGORY where
CATID = #value#
</select>
Dynamic SQL
<select id="getCategory" resultMap="categoryResult"
parameterClass="string">
select CATID, NAME, DESCN from CATEGORY
<dynamic prepend="WHERE">
<isParameterPresent>
where CATID = #value#
</isParameterPresent>
</dynamic>
</select>
Struts University Series