如何获取公共网页内容资源的InputStream? [英] How to obtain an InputStream of a public webcontent resource?

问题描述

我在我的 WAR 中打包了一组图像，我使用 在 中描绘了它们.图像位于 /resources/icons 文件夹中.我希望能够选择一个图像并在提交时将此图像的副本保存到磁盘.

这是怎么做到的?如何获得此图像的引用(InputStream 或其他)?

解决方案

鉴于此文件夹结构，

<前>你的项目|-- 源代码|`--com|`-- 示例|`--BackingBean.java|-- 网页内容||-- 元信息||-- 网络信息||-- 资源||`-- 图标||`--foo.png|`-- foo.xhtml:

您可以通过 ExternalContext#getResourceAsStream() 使用 webcontent-relative 路径:

ExternalContext externalContext = FacesContext.getCurrentInstance().getExternalContext();InputStream input = externalContext.getResourceAsStream("/resources/icons/foo.png");//...

或者通过 Resource#getInputStream() 其中 Resource 是从 ResourceHandler#createResource() 需要一个 /resources-相对路径:

ResourceHandler resourceHandler = FacesContext.getCurrentInstance().getApplication().getResourceHandler();InputStream input = resourceHandler.createResource("icons/foo.png").getInputStream();//...

至于选择图像并传递其路径，只需执行如下操作:

<f:ajax event="click" listener="#{bean.setImage(component.name)}"/></h:graphicImage><h:graphicImage name="icons/bar.png"><f:ajax event="click" listener="#{bean.setImage(component.name)}"/></h:graphicImage><h:commandButton value="submit" action="#{bean.saveImage}"/>

另见:

• getResourceAsStream() 与 FileInputStream
• 在基于 servlet 的应用程序中，在哪里放置以及如何读取配置资源文件?
• Maven 和 JSF webapp 结构，JSF资源到底放在哪里

I have a collection of images packaged in my WAR and I depict them in a <p:dataGrid> using <p:graphicImage>. The images are located in the /resources/icons folder. I want to be able to select an image and save a copy of this image to disk on submit.

How can this be done? How can I get a reference (InputStream or whatever) to this image?

解决方案

Given this folder structure,

YourProject
 |-- src
 |    `-- com
 |         `-- example
 |              `-- BackingBean.java
 |-- WebContent
 |    |-- META-INF
 |    |-- WEB-INF
 |    |-- resources
 |    |    `-- icons
 |    |         `-- foo.png
 |    `-- foo.xhtml
 :

You can get it by either ExternalContext#getResourceAsStream() which takes webcontent-relative path:

ExternalContext externalContext = FacesContext.getCurrentInstance().getExternalContext();
InputStream input = externalContext.getResourceAsStream("/resources/icons/foo.png");
// ...

Or by Resource#getInputStream() wherein Resource is obtained from ResourceHandler#createResource() which takes a /resources-relative path:

ResourceHandler resourceHandler = FacesContext.getCurrentInstance().getApplication().getResourceHandler();
InputStream input = resourceHandler.createResource("icons/foo.png").getInputStream();
// ...

As to selecting the image and passing its path around, just do something like as follows:

<h:graphicImage name="icons/foo.png">
    <f:ajax event="click" listener="#{bean.setImage(component.name)}" />
</h:graphicImage>
<h:graphicImage name="icons/bar.png">
    <f:ajax event="click" listener="#{bean.setImage(component.name)}" />
</h:graphicImage>
<h:commandButton value="submit" action="#{bean.saveImage}" />

See also:

• getResourceAsStream() vs FileInputStream
• Where to place and how to read configuration resource files in servlet based application?
• Maven and JSF webapp structure, where exactly to put JSF resources

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