How to XML escaping with Apache Velocity?

问题:

I am generating XML using Apache Velocity. What is the best (most straight-forward) way to XML-escape the output?

(I saw there is an escape tool, but could not figure out it's dev state. I also think that XML escaping is something that is very likely supported by Velocity directly.)

回答1:

Take a look at event handlers.

eventhandler.referenceinsertion.class = org.apache.velocity.app.event.implement.EscapeXmlReference

Escape tool is a production ready as well if you need to escape only selective references (final version of tools was released just recently but it was in beta stage before that for 2 years if not longer)

$esc.xml($var)

How to init velocity tools.

Include velocity-tools.xml into your project and enable required tools:

<tools> 
    <data type="number" key="TOOLS_VERSION" value="2.0"/>
    <data type="boolean" key="GENERIC_TOOLS_AVAILABLE" value="true"/>
    <toolbox scope="application">
        <tool class="org.apache.velocity.tools.generic.AlternatorTool"/>
        <tool class="org.apache.velocity.tools.generic.DisplayTool"/>
        <tool class="org.apache.velocity.tools.generic.MathTool"/>
        <tool class="org.apache.velocity.tools.generic.NumberTool"/>
        <tool class="org.apache.velocity.tools.generic.ComparisonDateTool"/>
        <tool class="org.apache.velocity.tools.generic.ClassTool"/>
        <tool class="org.apache.velocity.tools.generic.ConversionTool"/>
        <tool class="org.apache.velocity.tools.generic.EscapeTool"/>
        <tool class="org.apache.velocity.tools.generic.FieldTool"/>
        <tool class="org.apache.velocity.tools.generic.ListTool"/>
        <tool class="org.apache.velocity.tools.generic.ResourceTool"/>
        <tool class="org.apache.velocity.tools.generic.SortTool"/>
    </toolbox>
    <toolbox scope="request">
        <tool class="org.apache.velocity.tools.generic.LoopTool"/>
        <tool class="org.apache.velocity.tools.generic.ContextTool"/>
        <tool class="org.apache.velocity.tools.generic.LinkTool"/>
        <tool class="org.apache.velocity.tools.generic.RenderTool"/>
    </toolbox>
</tools>

Then velocity context creation procedure would look like:

ToolManager velocityToolManager = new ToolManager();
velocityToolManager.configure("velocity-tools.xml");
VelocityContext context = new VelocityContext(velocityToolManager.createContext());