在Freemarker模板中加载模板，而无需设置模板的目录或类

Question

Is there any way of loading the Freemarker templates directly without having need to first load the Directory from which templates will be loaded or setting the Class relative to which templates will be loaded.

ie Is there any way so that i can load a template like

Template template = getTemplate("PathToTemplate/myTemplate.ftl");

I need this, because user specifies the complete path to ftl files. So,first i have to separate directory name and file name, then i am doing

Configuration cfg = new Configuration();

int indexOfLast = templatePath.lastIndexOf("\\");
String dir = templatePath;
String fileName="";
if(indexOfLast>=0){
        dir = templatePath.substring(0,indexOfLast);
        fileName=  templatePath.substring(indexOfLast+1,templatePath.length());
}
cfg.setDirectoryForTemplateLoading(new File(dir));
Template template = cfg.getTemplate(fileName);

I do not want to do all this.

Answer 1

The getTemplate method is heavily overloaded. As per the documentation the method getTemplate(String, Locale, String, boolean) will eventually be called regardless which getTemplate method you called.

This method's documentation expresses the following:

The exact syntax of the name is interpreted by the underlying TemplateLoader, but the cache makes some assumptions. First, the name is expected to be a hierarchical path, with path components separated by a slash character (not with backslash!). The path (the name) given here must not begin with slash; it's always interpreted relative to the "template root directory".

There are two notable things:

1. The name parameter is already handling a hierarchical path, but must not begin with a slash. So maybe you could set the configuration's directory once to the root of your disk and then simply provide the full path (but without the leading slash).

2. The documentation explains something about a TemplateLoader . So you can simply write an implementation of that interface for loading the template. In that implementation you have full hands on the provided name .

Answer 2

Templates can be created by directly calling a Template constructor, to which you pass a String or Reader as argument. Then of course you get that Reader or String from wherever you want. This approach has two disadvantages though:

• Other templates won't be able to #import or #include those templates, as FreeMarker doesn't know how to load them (only you do)

• Caching those templates (if that's needed anyway) is up to you

If the above two is a problem for you, then see Seelenvirtuose's answer: create a TemplateLoader that interprets the template names as full paths.

As of your example code, know that the Configuration instance will clear its template cache every time you replace the TemplateLoader . Also note that it's not thread-safe to do.