servlet 整合freemarkder

Servlet与FreeMarker整合

http://oma1989.iteye.com/blog/1421804

SpringTemplateLoader

public class SpringTemplateLoader implements TemplateLoader {

	protected final Log logger = LogFactory.getLog(getClass());

	private final ResourceLoader resourceLoader;

	private final String templateLoaderPath;


	/**
	 * Create a new SpringTemplateLoader.
	 * @param resourceLoader the Spring ResourceLoader to use
	 * @param templateLoaderPath the template loader path to use
	 */
	public SpringTemplateLoader(ResourceLoader resourceLoader, String templateLoaderPath) {
		this.resourceLoader = resourceLoader;
		if (!templateLoaderPath.endsWith("/")) {
			templateLoaderPath += "/";
		}
		this.templateLoaderPath = templateLoaderPath;
		if (logger.isInfoEnabled()) {
			logger.info("SpringTemplateLoader for FreeMarker: using resource loader [" + this.resourceLoader +
					"] and template loader path [" + this.templateLoaderPath + "]");
		}
	}

	public Object findTemplateSource(String name) throws IOException {
		if (logger.isDebugEnabled()) {
			logger.debug("Looking for FreeMarker template with name [" + name + "]");
		}
		Resource resource = this.resourceLoader.getResource(this.templateLoaderPath + name);
		return (resource.exists() ? resource : null);
	}

	public Reader getReader(Object templateSource, String encoding) throws IOException {
		Resource resource = (Resource) templateSource;
		try {
			return new InputStreamReader(resource.getInputStream(), encoding);
		}
		catch (IOException ex) {
			if (logger.isDebugEnabled()) {
				logger.debug("Could not find FreeMarker template: " + resource);
			}
			throw ex;
		}
	}


	public long getLastModified(Object templateSource) {
		Resource resource = (Resource) templateSource;
		try {
			return resource.lastModified();
		}
		catch (IOException ex) {
			if (logger.isDebugEnabled()) {
				logger.debug("Could not obtain last-modified timestamp for FreeMarker template in " +
						resource + ": " + ex);
			}
			return -1;
		}
	}

	public void closeTemplateSource(Object templateSource) throws IOException {
	}

 FreeMarkerConfigurationFactory:

protected TemplateLoader getTemplateLoaderForPath(String templateLoaderPath) {
		if (isPreferFileSystemAccess()) {
			// Try to load via the file system, fall back to SpringTemplateLoader
			// (for hot detection of template changes, if possible).
			try {
				Resource path = getResourceLoader().getResource(templateLoaderPath);
				File file = path.getFile();  // will fail if not resolvable in the file system
				if (logger.isDebugEnabled()) {
					logger.debug(
							"Template loader path [" + path + "] resolved to file path [" + file.getAbsolutePath() + "]");
				}
				return new FileTemplateLoader(file);
			}
			catch (IOException ex) {
				if (logger.isDebugEnabled()) {
					logger.debug("Cannot resolve template loader path [" + templateLoaderPath +
							"] to [java.io.File]: using SpringTemplateLoader as fallback", ex);
				}
				return new SpringTemplateLoader(getResourceLoader(), templateLoaderPath);
			}
		}
		else {
			// Always load via SpringTemplateLoader (without hot detection of template changes).
			logger.debug("File system access not preferred: using SpringTemplateLoader");
			return new SpringTemplateLoader(getResourceLoader(), templateLoaderPath);
		}
	}

FreeMarkerConfigurationFactory:

public Configuration createConfiguration() throws IOException, TemplateException {
		Configuration config = newConfiguration();
		Properties props = new Properties();

		// Load config file if specified.
		if (this.configLocation != null) {
			if (logger.isInfoEnabled()) {
				logger.info("Loading FreeMarker configuration from " + this.configLocation);
			}
			PropertiesLoaderUtils.fillProperties(props, this.configLocation);
		}

		// Merge local properties if specified.
		if (this.freemarkerSettings != null) {
			props.putAll(this.freemarkerSettings);
		}

		// FreeMarker will only accept known keys in its setSettings and
		// setAllSharedVariables methods.
		if (!props.isEmpty()) {
			config.setSettings(props);
		}

		if (!CollectionUtils.isEmpty(this.freemarkerVariables)) {
			config.setAllSharedVariables(new SimpleHash(this.freemarkerVariables, config.getObjectWrapper()));
		}

		if (this.defaultEncoding != null) {
			config.setDefaultEncoding(this.defaultEncoding);
		}

		// Register template loaders that are supposed to kick in early.
		if (this.preTemplateLoaders != null) {
			this.templateLoaders.addAll(this.preTemplateLoaders);
		}

		// Register default template loaders.
		if (this.templateLoaderPaths != null) {
			for (String path : this.templateLoaderPaths) {
				this.templateLoaders.add(getTemplateLoaderForPath(path));
			}
		}
		postProcessTemplateLoaders(this.templateLoaders);

		// Register template loaders that are supposed to kick in late.
		if (this.postTemplateLoaders != null) {
			this.templateLoaders.addAll(this.postTemplateLoaders);
		}

		TemplateLoader loader = getAggregateTemplateLoader(this.templateLoaders);
		if (loader != null) {
			config.setTemplateLoader(loader);
		}

		postProcessConfiguration(config);
		return config;
	}