如果地图中不存在属性，如何使用 strsubsitutor 将模板字符串中的值替换为 null 或空字符串

Question

I have a string

String templateString = "The ${animal} jumps over the ${target}.";
valuesMap.put("animal", "quick brown fox");
StrSubstitutor sub = new StrSubstitutor(valuesMap);
String resolvedString = sub.replace(templateString);

But there is no entry for attr target in valuesMap. Final resolvedString would be The quick brown fox jumps over the ${target}.

Instead of ${target}, it need to be empty. Values in templatestring which doesn't have key in map should be empty or null.

required The quick brown fox jumps over the.

How to handle this

Answer 1

Your Map<String,String> valuesMap contains just the couple key, value "animal", "quick brown fox" , you have to add the couple "target", "" to your map like below:

String templateString = "The ${animal} jumps over the ${target}.";
valuesMap.put("animal", "quick brown fox");
valuesMap.put("target", ""); //<-- adding the new couple to the map
StrSubstitutor sub = new StrSubstitutor(valuesMap);
String resolvedString = sub.replace(templateString);