JSTL/EL如何方便高效的访问Constants和CodeTable（存储于DB的应用系统变量）

public class Constants implements Serializable {
	public static final String CONSTANT_A= "ABC";	
	...
}

<c:out value="${Constants.CONSTANT_A}"/>

<form:select path="gender">
  <form:option value="-" label="--Please Select"/>
  <form:options items="${CodeTable.Gender}" itemValue="codeValue" itemLabel="codeName"/>
</form:select>

...
public class ApplicationScopeLoader extends WebApplicationObjectSupport {

	private static final Logger logger = LoggerFactory.getLogger(ApplicationScopeLoader.class);
	
	/** constant classes which can be injected by spring */
	private Map<String, String> constantClass;

	protected void initApplicationContext() {
		try {
			//build constants and put it to the application scope
			this.buildConstants();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
	
	/**
	 * build constants map
	 * 
	 * @return constants map
	 * @throws ClassNotFoundException 
	 */
	private void buildConstants() throws ClassNotFoundException{
		Map<String, Object> result = new HashMap<String, Object>();
		for(Map.Entry<String, String> map: constantClass.entrySet()){
			//the constant group name
			String k = map.getKey();
			//the class
			String v = map.getValue();
			Class<?> clazz = this.getClass().getClassLoader().loadClass(v);
			Field[] fields = clazz.getDeclaredFields();
			for (int i = 0; i < fields.length; i++) {
				Field field = fields[i];
				int modifier = field.getModifiers();
				//must be final & public
				if (Modifier.isFinal(modifier) && !Modifier.isPrivate(modifier))
					try {
						String name = field.getName();
						Object value = field.get(this);
						logger.debug("building constants{}: name={},value={}", 
								new Object[]{k, name,value});
						result.put(name, value);
					} catch (IllegalAccessException e) {
					}
			}

			logger.info("put constant [{}] to application scope.", k);
			this.getServletContext().setAttribute(k, result);
		}
	}

	public Map<String, String> getConstantClass() {
		return constantClass;
	}

	public void setConstantClass(Map<String, String> constantClass) {
		this.constantClass = constantClass;
	}

}

<bean name="applicationScopeLoader" class="xxx.utils.ApplicationScopeLoader" lazy-init="false">
  <property name="constantClass">
    <map>
      <entry key="Constants" value="xxx.framework.Constants"/>
      <!-- 
      <entry key ="Constants2" value="another.constants.class"/>
      -->
    </map>
  </property>
</bean>

${Constants.PAGE_SIZE_DEFAULT}

public class ApplicationScopeLoader extends WebApplicationObjectSupport {
...
	
  /** code table service */
  private final CodeTableLoaderService codeTableLoaderService = ApplicationContextManager
		.getBean("codeTableLoaderService",CodeTableLoaderService.class);
	
  private final static String CODE_TABLE_CONTEXT_NAME = "CodeTable";

  protected void initApplicationContext() {
    try {
      //build constants and put it to the application scope
      this.buildConstants();
			
      //build code table and put it to the application scope
      this.buildCodeTables();
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
	
  /**
   * build code tables
   * each code table will be group by the type
   * for example, if there is a code table type 'gender'
   * then will be put to 
   */
  private void buildCodeTables(){
    String[] codeTypes = codeTableLoaderService.loadAllCodeTypes();
	for(String codeType: codeTypes){
		this.buildOneCodeTableByCodeType(codeType);
	}
  }

  /**
   * extract given codes to a sub array of codes by code type
   * @param codes
   * @return
   */
  private void buildOneCodeTableByCodeType(String codeType){
	Map<Object,Object> codeMap = new HashMap<Object,Object>() {
            private static final long serialVersionUID = -1759893921358235848L;
            
            /**
             * get from the service, not raw data for avoiding non-refresh issue
             */
            public Object get(Object key) {
                return codeTableLoaderService.getCodesByType(String.valueOf(key));
            }

            public boolean containsKey(Object key) {
                return true;
            }
        };
		
	logger.debug("put code table of [{}] to application scope.", codeType);
	this.getServletContext().setAttribute(CODE_TABLE_CONTEXT_NAME, codeMap);
  }
}

/**
 * It's a code table loading service 
 * for exporting code tables to application scope
 * 
 * but we don't put the dummy data to application scope directly
 * for avoiding non-refreshable issue
 * 
 * @author bright_zheng
 *
 */
public interface CodeTableLoaderService {

	/**
	 * load all code types from db/cache
	 * 
	 * @return an array including all code types
	 */
	public String[] loadAllCodeTypes();
	
	/**
	 * get all code objects/beans filter by code type
	 * 
	 * @param codeType
	 * @return responding code objects/beans
	 */
	public Object[] getCodesByType(String codeType);
}

public class ApplicationScopeLoader extends WebApplicationObjectSupport {
...
	
  /** code table service */
  private final CodeTableLoaderService codeTableLoaderService = ApplicationContextManager
		.getBean("codeTableLoaderService",CodeTableLoaderService.class);
	
  private final static String CODE_TABLE_CONTEXT_NAME = "CodeTable";

  protected void initApplicationContext() {
    try {
      //build constants and put it to the application scope
      this.buildConstants();
			
      //build code table and put it to the application scope
      this.buildCodeTables();
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
	
  /**
   * build code tables
   * each code table will be group by the type
   * for example, if there is a code table type 'gender'
   * then will be put to 
   */
  private void buildCodeTables(){
    String[] codeTypes = codeTableLoaderService.loadAllCodeTypes();
	for(String codeType: codeTypes){
		this.buildOneCodeTableByCodeType(codeType);
	}
  }

  /**
   * extract given codes to a sub array of codes by code type
   * @param codes
   * @return
   */
  private void buildOneCodeTableByCodeType(String codeType){
	Map<Object,Object> codeMap = new HashMap<Object,Object>() {
            private static final long serialVersionUID = -1759893921358235848L;
            
            /**
             * get from the service, not raw data for avoiding non-refresh issue
             */
            public Object get(Object key) {
                return codeTableLoaderService.getCodesByType(String.valueOf(key));
            }

            public boolean containsKey(Object key) {
                return true;
            }
        };
		
	logger.debug("put code table of [{}] to application scope.", codeType);
	this.getServletContext().setAttribute(CODE_TABLE_CONTEXT_NAME, codeMap);
  }
}

/**
 * It's a code table loading service 
 * for exporting code tables to application scope
 * 
 * but we don't put the dummy data to application scope directly
 * for avoiding non-refreshable issue
 * 
 * @author bright_zheng
 *
 */
public interface CodeTableLoaderService {

	/**
	 * load all code types from db/cache
	 * 
	 * @return an array including all code types
	 */
	public String[] loadAllCodeTypes();
	
	/**
	 * get all code objects/beans filter by code type
	 * 
	 * @param codeType
	 * @return responding code objects/beans
	 */
	public Object[] getCodesByType(String codeType);
}

--这里用了Spring的TAG，当然谁的TAG并不是关键
<form:select path="hotel.country">
 <form:option value="-" label="--Please Select"/>
 <form:options items="${CodeTable.Gender}" itemValue="codeValue" itemLabel="codeName"/>
</form:select>

<c:forEach var="ct" items="${CodeTable.Gender}">
  -->codeName: ${ct.codeName},  
  -->codeValue: ${ct.codeValue},  
  -->codeDesc: ${ct.codeDesc}<br> 
</c:forEach> 

public class CodeTable implements Serializable {
  private String codeType;
  private String codeName;
  private String codeValue;
  private String codeDesc;
  
  //getter/setter omitted
  ...
}

JspFactory.getJspApplicationContext(javax.servlet.ServletContext).addELResolver(ELResorver resolver)