JFinal 源码导读第四天(3) initRender

1.接上面的文章,initRender(); 

	private void initRender() {
		RenderFactory renderFactory = RenderFactory.me();
		renderFactory.init(constants, servletContext);
	}
	

2.renderFactory.init(constants, servletContext);总的来说,这是主要是初始化FreeMarker,Velocity等模板

public void init(Constants constants, ServletContext servletContext) {
		this.constants = constants;
		RenderFactory.servletContext = servletContext;
		
		// init Render
		Render.init(constants.getEncoding(), constants.getDevMode());
		initFreeMarkerRender(servletContext);
		initVelocityRender(servletContext);
		initFileRender(servletContext);
		
		// create mainRenderFactory
		if (mainRenderFactory == null) {
			ViewType defaultViewType = constants.getViewType();
			if (defaultViewType == ViewType.FREE_MARKER)
				mainRenderFactory = new FreeMarkerRenderFactory();
			else if (defaultViewType == ViewType.JSP)
				mainRenderFactory = new JspRenderFactory();
			else if (defaultViewType == ViewType.VELOCITY)
				mainRenderFactory = new VelocityRenderFactory();
			else
				throw new RuntimeException("View Type can not be null.");
		}
		
		// create errorRenderFactory
		if (errorRenderFactory == null) {
			errorRenderFactory = new ErrorRenderFactory();
		}
	}
	

3.initFreeMarkerRender 主要就是java初始化FreeMarker模版代码比较简单,自己看看应该会懂

private void initFreeMarkerRender(ServletContext servletContext) {
		try {
			Class.forName("freemarker.template.Template");	// detect freemarker.jar
			FreeMarkerRender.init(servletContext, Locale.getDefault(), constants.getFreeMarkerTemplateUpdateDelay());
		} catch (ClassNotFoundException e) {
			// System.out.println("freemarker can not be supported!");
		}
	}

  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);  config.setNumberFormat("#0.#####");
    }
    

4.initVelocityRender(servletContext);主要是java初始化Velocity模版

	static void init(ServletContext servletContext) {
		String webPath = servletContext.getRealPath("/");
		properties.setProperty(Velocity.FILE_RESOURCE_LOADER_PATH, webPath);
		properties.setProperty(Velocity.ENCODING_DEFAULT, encoding); 
		properties.setProperty(Velocity.INPUT_ENCODING, encoding); 
		properties.setProperty(Velocity.OUTPUT_ENCODING, encoding);
	}
	

5.initFileRender(servletContext);主要是java初始化FileRead,主要用于下载文件的,我顺便把他的reader()代码也贴出来吧,
这个reader()什么时候执行,在doFilter里面我会介绍

	static void init(String fileDownloadPath, ServletContext servletContext) {
		FileRender.fileDownloadPath = fileDownloadPath;
		FileRender.servletContext = servletContext;
		webRootPath = PathKit.getWebRootPath();
	}
	public static String getWebRootPath() {
		if (webRootPath == null)
			webRootPath = detectWebRootPath();;
		return webRootPath;
	}
		private static String detectWebRootPath() {
		try {
			String path = PathKit.class.getResource("/").toURI().getPath();
			return new File(path).getParentFile().getParentFile().getCanonicalPath();
		} catch (Exception e) {
			throw new RuntimeException(e);
		}
	}

	public void render() {
		if (fileName != null) {
			if (fileName.startsWith("/"))
				file = new File(webRootPath + fileName);
			else
				file = new File(fileDownloadPath + fileName);
		}
		
		if (file == null || !file.isFile() || file.length() > Integer.MAX_VALUE) {
            // response.sendError(HttpServletResponse.SC_NOT_FOUND);
            // return;
			
			// throw new RenderException("File not found!");
			RenderFactory.me().getErrorRender(404).setContext(request, response).render();
			return ;
        }
		
		try {
			response.addHeader("Content-disposition", "attachment; filename=" + new String(file.getName().getBytes("GBK"), "ISO8859-1"));
		} catch (UnsupportedEncodingException e) {
			response.addHeader("Content-disposition", "attachment; filename=" + file.getName());
		}
		
        String contentType = servletContext.getMimeType(file.getName());
        if (contentType == null) {
        	contentType = DEFAULT_FILE_CONTENT_TYPE;		// "application/octet-stream";
        }
        
        response.setContentType(contentType);
        response.setContentLength((int)file.length());
        InputStream inputStream = null;
        OutputStream outputStream = null;
        try {
            inputStream = new BufferedInputStream(new FileInputStream(file));
            outputStream = response.getOutputStream();
            byte[] buffer = new byte[1024];
            for (int n = -1; (n = inputStream.read(buffer)) != -1;) {
                outputStream.write(buffer, 0, n);
            }
            outputStream.flush();
        }
        catch (Exception e) {
        	throw new RenderException(e);
        }
        finally {
            if (inputStream != null) {
                try {
					inputStream.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
            }
            if (outputStream != null) {
            	try {
					outputStream.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
            }
        }
	}

6.mainRenderFactory = new FreeMarkerRenderFactory(); 我就解释这个把,这里运用了 抽象工厂模式,跟JFinal里面的Logger的JDKLogger和Logger4j类似