Spring

Overview

Spring is a platform for building Java application, and it includes many easy-to-use solutions for building web-based application.

Here we discuss how to use Spring with ZK, especially the use of DelegatingVariableResolver. It provides the basic support of Spring which allows a ZUML document to access variables defined in Spring. For more comprehensive support, such as Spring scopes, annotations and security, please refer to another product: ZK Spring.

Installing Spring

First you have to install Spring to your Web application. If you are familiar with Spring, you could skip this section. In this section we use Spring core 3.0.2 and Spring Security 3.0.2.

Copy Spring binaries into your Web library

Before using Spring, you have to download it, and put the jar file into the directory of your web application.

1. Download Spring Core framework 3.0.2 release binaries download

• • org.springframework.aop-3.0.2.RELEASE.jar
  • org.springframework.asm-3.0.2.RELEASE.jar
  • org.springframework.beans-3.0.2.RELEASE.jar
  • org.springframework.context-3.0.2.RELEASE.jar
  • org.springframework.context.support-3.0.2.RELEASE.jar
  • org.springframework.core-3.0.2.RELEASE.jar
  • org.springframework.expression-3.0.2.RELEASE.jar
  • org.springframework.transaction-3.0.2.RELEASE.jar
  • org.springframework.web-3.0.2.RELEASE.jar
  • org.springframework.web.servlet-3.0.2.RELEASE.jar

Put these jar files into your $myApp/WEB-INF/lib/. Here $myApp represents the name of your web application.

Configure web.xml

In your web.xml, you have to define org.springframework.web.context.ContextLoaderListener, and to specify the location of the configuration file to load bean definitions.

<context-param>
  <param-name>contextConfigLocation</param-name>
  <param-value>/WEB-INF/applicationContext.xml</param-value>
</context-param>
 
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>

Create Spring Configuration File

Define bean definitions in applicationContext.xml file, and put it into your WEB-INF directory.

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">
 
<beans>
  <bean id="DataSource" class="test.DataSourceImpl"/>
</beans>

Creating Spring Bean Class

Then you have to define a DataSource interface and its implementation:

DataSource.java

 package test;
 
 public interface DataSource
 {
     java.util.List getElementsList();
 }

DataSourceImpl.java

 package test;
 
 import java.util.*;
 
 public class DataSourceImpl implements DataSource
 {
     public List getElementsList()
     {
         List list = new ArrayList();
         list.add("Tom");
         list.add("Henri");
         list.add("Jim");
         
         return list;
     }
 }

Accessing Spring Bean in the ZUML page

There are two ways to access Spring-Managed beans in your ZUML page. One is using variable-resolver, and the other is using SpringUtil. Which to use depends on your usage, in the ZUML page, we suggest you to use variable-resolver.

Using variable-Resolver

Simply declare the variable-resolver with DelegatingVariableResolver on top of your ZUML page, then, in the rest of your page, you can access any Spring-Managed beans directly using its bean-id.

<?variable-resolver class="org.zkoss.zkplus.spring.DelegatingVariableResolver"?>
<window>
  <grid>
    <rows>
      <row forEach="${DataSource.elementsList}">
        <label value="${each}"/>
      </row>
    </rows>
  </grid>
</window>

variable-resolver will look-up the bean named DataSource automatically for you, and returned a list to the forEach loop.

Use with Composer

GenericAutowireComposer will wire the variables defined in the variable resolvers. Thus, we could declare DelegatingVariableResolver in the ZUML document, and then declare the Spring-managed bean as a control directly in a composer. For example,

<?variable-resolver class="org.zkoss.zkplus.spring.DelegatingVariableResolver"?>
<window apply="foo.MyComposer">
...
    <textbox id="password"/>
...
    <button id="submit" label="Change"/>
</window>

Then, if a data member's name matches a Spring-managed bean, it will be wired automatically too. For example,

public class PasswordSetter extends GenericFowardComposer {
    private User user; //wired automatically if user is a spring-managed bean
    private Textbox password; //wired automatically if there is a textbox named password

    public void onClick$submit() {
        user.setPassword(password.getValue());
    }
}

For more information, please refer to MVC: Controller.

Using SpringUtil

org.zkoss.zkplus.spring.SpringUtil is a utility class which allows you to get Spring-managed beans in Java code with ease.

<window>
 <zscript><![CDATA[	
   import org.zkoss.zkplus.spring.SpringUtil;
   import test.*;
  
   DataSource dataSource = SpringUtil.getBean("DataSource");
   List list = dataSource.getElementsList();
 ]]></zscript>
  
 <grid>
   <rows>
     <row forEach="${list}">
       <label value="${each}"/>
     </row>
   </rows>
 </grid>
</window>

Where the forEach loop is looping over the collection to print the ${each} attribute on each object in the collection.

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