http://wiki.jboss.org/wiki/Wiki.jsp?page=RulesWithSpringFramework is an excellent article on how to do this. I have made some slight modifications to this to use excel files instead of drl files and pass in a path rather than specify each file individually. Here is the code and configuration

<bean id=”huntGroupRuleBase” class=”edu.apollogrp.qtask.routing.util.RuleBaseBeanFactory”>
<property name=”drlResourcePath” value=”classpath:hunt-group-rules/*.xls”/>
<property name=”packageBuilderConfiguration”>
<bean class=”org.drools.compiler.PackageBuilderConfiguration”>
<!–<property name=”compiler” value=”PackageBuilderConfiguration.JANINO”/> –>
<property name=”compiler” value=”1″/>
</bean>
</property
</bean>

package edu.apollogrp.qtask.routing.util;

import java.io.InputStreamReader;
import java.io.Reader;
import java.io.StringReader;
import java.util.List;

import org.apache.log4j.Logger;
import org.drools.RuleBase;
import org.drools.RuleBaseFactory;
import org.drools.compiler.PackageBuilder;
import org.drools.compiler.PackageBuilderConfiguration;
import org.drools.decisiontable.InputType;
import org.drools.decisiontable.SpreadsheetCompiler;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.FactoryBean;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.core.io.Resource;
import org.springframework.util.Assert;

/**
* @author Geoffrey De Smet
* @see http://wiki.jboss.org/wiki/Wiki.jsp?page=RulesWithSpringFramework
*
*/
public class RuleBaseBeanFactory implements FactoryBean, InitializingBean,
ApplicationContextAware {

private static final Logger log = Logger
.getLogger(RuleBaseBeanFactory.class);

private String drlResourcePath;

private RuleBase ruleBase;

private PackageBuilderConfiguration packageBuilderConfiguration;

private ApplicationContext applicationContext;

public void afterPropertiesSet() throws Exception {
Resource[] drlResourceList = applicationContext
.getResources(drlResourcePath);

Assert.notEmpty(drlResourceList, “drlResourceList must not be empty”);

PackageBuilder builder = (packageBuilderConfiguration != null ? new PackageBuilder(
packageBuilderConfiguration)
: new PackageBuilder());

SpreadsheetCompiler compiler = new SpreadsheetCompiler();

for (Resource resource : drlResourceList) {
log.info(“Reading file: ” + resource.getFilename());

Reader input = null;

// check the extension to see if this is a decision table or regular
// drl
if (resource.getFilename().endsWith(“drl”)) {
input = new InputStreamReader(resource.getInputStream());
} else if (resource.getFilename().endsWith(“xls”)) {
String drl = compiler.compile(resource.getInputStream(),
InputType.XLS);
log.debug(drl);
input = new StringReader(drl);
} else {
log.warn(“Drools resource has unknown file type: ”
+ resource.getFilename());
}
if (input != null) {
builder.addPackageFromDrl(input);
}
}
ruleBase = RuleBaseFactory.newRuleBase();
ruleBase.addPackage(builder.getPackage());
}

public RuleBase getObject() {
return ruleBase;
}

public Class getObjectType() {
return RuleBase.class;
}

public boolean isSingleton() {
return true;
}

public void setPackageBuilderConfiguration(
PackageBuilderConfiguration packageBuilderConfiguration) {
this.packageBuilderConfiguration = packageBuilderConfiguration;
}

public void setApplicationContext(ApplicationContext applicationContext)
throws BeansException {
this.applicationContext = applicationContext;
}

public void setDrlResourcePath(String drlResourcePath) {
this.drlResourcePath = drlResourcePath;
}

}