Freemarker调用java静态方法和属性、枚举，支持国际化等

1. 调用静态方法和属性以及枚举，这个不多说，网上例子很多
2. FreeMarkerTag这是很有特色的类，通过这个可以实现国际化…各种功能，比如Springmvc、activeWeb等都借助这个支持了国际化功能

示例

package org.javalite.activeweb.freemarker;

import freemarker.template.SimpleScalar;
import org.javalite.activeweb.Messages;

import java.io.Writer;
import java.util.ArrayList;
import java.util.List;
import java.util.Locale;
import java.util.Map;

import static org.javalite.common.Util.split;

/**
 * The message tag is designed to display messages in view templates. Message values are defined in resource bundle called
 * \"activeweb_messages\". This means that  this tag will be looking for file called <code>activeweb_messages.properties</code> as default
 * name and others, such as <code>activeweb_messages_fr_FR.properties</code> in case French locale was specified.
 *
 * <p>
 *     Examples:
 * </p>
 *
 * <h4>Simple usage</h4>
 *  Given that there is a file <code>activeweb_messages.properties</code> with content:<br/>
 *  <pre>
greeting=Hello!
 *  </pre>
 *  and tag code:
 *
 *  <pre>
&lt;@message key=&quot;greeting&quot;/&gt;
 *  </pre>
 *  then the output will be:
 *  <pre>
Hello!
 *  </pre>
 *
 * <h4>Message with parameters</h4>
 * Lets say a message in resource bundle is declared like this:
 *
 * <pre>
meeting=Meeting will take place on {0} at {1}
 * </pre>
 *
 * You can then specify the tag with parameters:
 * <pre>
&lt;@message key=&quot;meeting&quot; param0=&quot;Wednesday&quot; param1=&quot;2:00 PM&quot;/&gt;
 * </pre>
 *
 * When a view template renders, the outcome will be:
 *
 * <pre>
Meeting will take place on Wednesday at 2:00 PM
 * </pre>
 *
 *  <h4>Defaulting to key if value not found</h4>
 *
 *  In case a resource bundle does not have a key specified, the key is rendered as value verbatim:
 *
 *  <pre>
&lt;@message key=&quot;greeting&quot;/&gt;
 *  </pre>
 *
 *  The output:
 *  <pre>
greeting
 *  </pre>
 *
 *
 * <h4>Detection of locale from request</h4>
 *
 * If there is a locale on the request supplied by the agent, then this locale is automatically picked up by this tag.
 * For instance, if a browser supplies locale \"fr_FR\" and there is a corresponding resource bundle:
 * \"activeweb_messages_fr_FR.properties\", with this property:
 *
 * <pre>
greeting=Bonjour!
 * </pre>
 *
 * then this tag:
 * <pre>
&lt;@message key=&quot;greeting&quot;/&gt;
 * </pre>
 * will produce:
 * <pre>
Bonjour!
 * </pre>
 *
 * <h4>Overriding request locale</h4>
 * There is a \"locale\" argument you can pass to the tag to override the locale from request:
 * <pre>
&lt;@message key=&quot;greeting&quot; locale=&quot;de_DE&quot;/&gt;
 * </pre>
 *
 *
 *
 * @author Igor Polevoy: 8/15/12 3:50 PM
 */
public class MessageTag extends FreeMarkerTag {

    @Override
    protected void render(Map params, String body, Writer writer) throws Exception {
        if (params.containsKey(\"key\")) {
            String key = params.get(\"key\").toString();
            if(params.containsKey(\"locale\")){
                String localeString = params.get(\"locale\").toString();
                String language, country;
                Locale locale;
                if(localeString.contains(\"_\")){
                    language = split(localeString, \'_\')[0];
                    country = split(localeString, \'_\')[1];
                    locale = new Locale(language, country);
                }else{
                    language = localeString;
                    locale = new Locale(language);
                }
                writer.write(Messages.message(key, locale, getParamsArray(params)));
            }else{
                writer.write(Messages.message(key, getParamsArray(params)));
            }
        }else{
             writer.write(\"<span style=\\\"display:none\\\">you failed to supply key for this message tag</span>\");
        }
    }


    private String[] getParamsArray(Map params) {

        int index = 0;
        List<String> paramList = new ArrayList<String>();
        for (String paramName = \"param\"; params.containsKey(paramName + index); index++){
            String param = ((SimpleScalar) params.get(paramName + index)).getAsString();
            paramList.add(param);
        }
        return paramList.toArray(new String[]{});
    }
}

注册一下即可使用

class Config {
	private Configuration config;
	public Config() {
		config.setSharedVariable(\"message\", new MessageTag());
	}
}