FreeMarkerRender.java

/**
 * Copyright (c) 2011-2013, James Zhan 詹波 (jfinal@126.com).
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package net.tooan.ynpay.third.jfinal.render;

import freemarker.template.*;

import javax.servlet.ServletContext;
import java.io.PrintWriter;
import java.util.*;

/**
 * FreeMarkerRender.
 */
public class FreeMarkerRender extends Render {

    private static final long serialVersionUID = -7649769283048920381L;
    private transient static final String encoding = getEncoding();
    private transient static final String contentType = "text/html; charset=" + encoding;
    private transient static final Configuration config = new Configuration();

    public FreeMarkerRender(String view) {
        this.view = view;
    }

    /**
     * freemarker can not load freemarker.properies automatically
     */
    public static Configuration getConfiguration() {
        return config;
    }

    /**
     * Set freemarker's property.
     * The value of template_update_delay is 5 seconds.
     * Example: FreeMarkerRender.setProperty("template_update_delay", "1600");
     */
    public static void setProperty(String propertyName, String propertyValue) {
        try {
            FreeMarkerRender.getConfiguration().setSetting(propertyName, propertyValue);
        } catch (TemplateException e) {
            throw new RuntimeException(e);
        }
    }

    public static void setProperties(Properties properties) {
        try {
            FreeMarkerRender.getConfiguration().setSettings(properties);
        } catch (TemplateException e) {
            throw new RuntimeException(e);
        }
    }

    static void init(ServletContext servletContext, Locale locale, int template_update_delay) {
        // Initialize the FreeMarker configuration;
        // - Create a configuration instance
        // config = new Configuration();
        // - Templates are stoted in the WEB-INF/templates directory of the Web app.
        config.setServletContextForTemplateLoading(servletContext, "/");    // "WEB-INF/templates"
        // - Set update dealy to 0 for now, to ease debugging and testing.
        //   Higher value should be used in production environment.

        if (getDevMode()) {
            config.setTemplateUpdateDelay(0);
        } else {
            config.setTemplateUpdateDelay(template_update_delay);
        }

        // - Set an error handler that prints errors so they are readable with
        //   a HTML browser.
        // config.setTemplateExceptionHandler(TemplateExceptionHandler.HTML_DEBUG_HANDLER);
        config.setTemplateExceptionHandler(TemplateExceptionHandler.RETHROW_HANDLER);

        // - Use beans wrapper (recommmended for most applications)
        config.setObjectWrapper(ObjectWrapper.BEANS_WRAPPER);
        // - Set the default charset of the template files
        config.setDefaultEncoding(encoding);        // config.setDefaultEncoding("ISO-8859-1");
        // - Set the charset of the output. This is actually just a hint, that
        //   templates may require for URL encoding and for generating META element
        //   that uses http-equiv="Content-type".
        config.setOutputEncoding(encoding);            // config.setOutputEncoding("UTF-8");
        // - Set the default locale
        config.setLocale(locale /* Locale.CHINA */);        // config.setLocale(Locale.US);
        config.setLocalizedLookup(false);

        // 去掉int型输出时的逗号, 例如: 123,456
        // config.setNumberFormat("#");		// config.setNumberFormat("0"); 也可以
        config.setNumberFormat("#0.#####");
    }

    @SuppressWarnings({"unchecked", "rawtypes"})
    public void render() {
        response.setContentType(contentType);
        Enumeration<String> attrs = request.getAttributeNames();
        Map root = new HashMap();
        while (attrs.hasMoreElements()) {
            String attrName = attrs.nextElement();
            root.put(attrName, request.getAttribute(attrName));
        }

        PrintWriter writer = null;
        try {
            Template template = config.getTemplate(view);
            writer = response.getWriter();
            template.process(root, writer);        // Merge the data-model and the template
        } catch (Exception e) {
            throw new RenderException(e);
        } finally {
            if (writer != null)
                writer.close();
        }
    }
}