Freemarker的get-method无需"get" [英] Freemarker get-method without "get"

问题描述

如何使用以下语法访问方法/字段: ${object.foo} ?
我想要的是:
如果有一个名为foo的公共字段，则返回值，
否则，如果有一个名为getFoo()的吸气剂，则它将调用并返回调用结果，
否则，如果有一个名为foo()的方法，则它将调用并返回调用结果.
Freemarker中有可能吗?

How can I access method/field, using the following syntax: ${object.foo} ?
What i want is:
if there is a public field, named foo, then it's value returns,
else if there is a getter, named getFoo(), then it calls and result of call returns,
else if there is a method, named foo(), then it calls and result of call returns.
Is it possible in Freemarker?

推荐答案

由于您可以编写自己的ObjectWrapper实现，因此有可能，尽管如果您需要多个object.foo来工作(例如，公开方法等)，则可以进行编写对象包装程序可以是很多的工作.因此，也许最好的折衷方法是使用DefaultObjectWrapper或BeansWrapper.在哪里配置FreeMarker:

Since you can write your own ObjectWrapper implementation it's possible, although if you need more than object.foo to work (like, exposing methods etc.) writing an object wrapper can be a lot of work. So, maybe a good compromise is using DefaultObjectWrapper or BeansWrapper. Where you configure FreeMarker:

BeansWrapper bw = new DefaultObjectWrapper() {

    @Override
    protected void finetuneMethodAppearance(
            Class clazz, Method m, MethodAppearanceDecision decision) {
        if (m.getDeclaringClass() != Object.class
                && m.getReturnType() != void.class
                && m.getParameterTypes().length == 0) {
            String mName = m.getName();
            if (!(mName.startsWith("get")
                    && (mName.length() == 3
                       || Character.isUpperCase(mName.charAt(3))))) {
                decision.setExposeMethodAs(null);
                try {
                    decision.setExposeAsProperty(new PropertyDescriptor(
                            mName, clazz, mName, null));
                } catch (IntrospectionException e) {  // Won't happen...
                    throw new RuntimeException(e); 
                }
            }
        }
    }

};
bw.setExposeFields(true);

cfg.setObjectWrapper(bw);

优先级并不完全是您想要的. object.foo将按以下顺序尝试操作:getFoo()，foo()，foo

The priorities aren't exactly what you wanted though. object.foo will try things in this order: getFoo(), foo(), foo

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