velocity输出csv的一种做法

 

使用spring mvc + velocity做项目时，输出csv文件做法是在controller自行调用httpResponse输出。

如果希望通过velocity输出csv内容，以下提供一种实现方式

 

 

1.新增ToCSVView,继承自VelocityView,重写rander方法,内容为设置http header与content type

public class ToCSVView extends VelocityView {
	
	/**
	 * Process the model map by merging it with the Velocity template.
	 * Output is directed to the servlet response.
	 * <p>This method can be overridden if custom behavior is needed.
	 */
	protected void renderMergedTemplateModel(
			Map model, HttpServletRequest request, HttpServletResponse response) throws Exception {

		exposeHelpers(model, request);

		Context velocityContext = createVelocityContext(model, request, response);
		exposeHelpers(velocityContext, request, response);
		exposeToolAttributes(velocityContext, request);

		
		doRender(velocityContext, response);
	
		//以下为我们自行的修改
		String fileName = "data.csv";
		
		response.setContentType("text/plain;charset=gbk");
		response.setHeader("Content-Disposition", "attachment;filename=\""
				+ fileName + "\"");

		// 确保IE识别本次为下载文件
		response.setHeader("Content-Transfer-Encoding", "binary");
		response.setHeader("Cache-Control",
				"must-revalidate, post-check=0, pre-check=0");
		response.setHeader("Pragma", "public");
	}
}

 

2.新增ToCSVViewResolver,继承自VelocityViewResolver,重写loadView方法,后缀是csv进行渲染。

public class ToCSVViewResolver extends org.springframework.web.servlet.view.velocity.VelocityViewResolver implements Ordered {
	public static final String VIEW_CSV = ".csv"; 
	
	/* (non-Javadoc)
	 * @see org.springframework.web.servlet.view.AbstractCachingViewResolver#loadView(java.lang.String, java.util.Locale)
	 */
	@Override
	protected View loadView(String viewName, Locale locale) throws Exception {
		if(viewName.endsWith(VIEW_CSV)) {
			AbstractUrlBasedView view = buildView(viewName);
			return (View) getApplicationContext().getAutowireCapableBeanFactory().initializeBean(view, viewName);
		}
		return null;
	}

 

3.ToCSVViewResolver重写buildView方法,使用我们的ToCSVView进行渲染,从而实现content-type和http头的修改

protected AbstractUrlBasedView buildView(String viewName) throws Exception {
		ToCSVView view = (ToCSVView) super.buildView(viewName);
		view.setVelocityFormatterAttribute(this.velocityFormatterAttribute);
		view.setDateToolAttribute(this.dateToolAttribute);
		view.setNumberToolAttribute(this.numberToolAttribute);
		if (this.toolboxConfigLocation != null) {
//			((VelocityToolboxView) view).setToolboxConfigLocation(this.toolboxConfigLocation);
		}
		return view;
	}

 

4.ToCSVViewResolver参数配置拷贝自velocity配置

<bean id="toCSVViewResolver" class="view.ToCSVViewResolver">
  <property name="prefix" value="/"></property>
  <property name="suffix" value=".vm"></property>
  <property name="exposeSpringMacroHelpers" value="true" />
  <property name="exposeRequestAttributes" value="true" />
  <property name="exposeSessionAttributes" value="true" />
  <property name="allowRequestOverride" value="true" />
  <property name="allowSessionOverride" value="true" />
  <property name="contentType" value="text/plain;charset=gbk" />
  <property name="order" value="5"></property>
 </bean>

 

5.检查dispatcher-servlet是否接收了csv后缀的请求，检查完毕就可以测试了~~写一个controller,页面为vm,打开后识别为下载文件

 

 test.vm文件

日期,数量
#foreach($info in $infoList)
$info.date,$info.count
#end