无法使用 FreeMarker 访问混合（驼峰式）大小写 Java 变量名称
我正在使用 FreeMarker (2.3.18) 访问自定义类中的 Java 变量。当变量名称混合大小写（驼峰式大小写）时，我收到一条错误消息，指出该变量不存在。
这是我的课程的片段：
public class Student{
private String name_last, nameFirst;
public String getName_last(){
return name_last;
}
public String getNameFirst(){
return nameFirst;
}
}
在我的 FreeMarker 模板中，${passedInStudent.name_last} 成功返回值，但 ${passedInStudent.nameFirst} - 返回一个错误，指出
freemarker.core.InvalidReferenceException: Expression
passedInStudent.nameFirst is undefined on line ...
- Is在 FreeMarker 中使用驼峰式大小写变量名称是否存在已知问题？
- 这可能是这个特定版本的 FreeMarker 的问题吗？
- 有什么配置可以控制吗？
- 我访问这些变量的方式还有其他问题吗？
I am using FreeMarker (2.3.18) to access Java variables in a custom class. When the variable name has mixed case (camel case) I'm getting an error message saying the variable does not exist.
This is a snippet of my class:
public class Student{
private String name_last, nameFirst;
public String getName_last(){
return name_last;
}
public String getNameFirst(){
return nameFirst;
}
}
In my FreeMarker template, ${passedInStudent.name_last} returns the value successfully but ${passedInStudent.nameFirst} - returns an error saying
freemarker.core.InvalidReferenceException: Expression
passedInStudent.nameFirst is undefined on line ...
- Is there a known issue with using camel case variable names in FreeMarker?
- Is it maybe an issue with this specific version of FreeMarker?
- Is there a configuration to control it?
- Is there something else wrong with the way I am accessing these variables?
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评论（2）
你的代码应该可以工作。当然
nameFirst是null，因此就 FreeMarker 而言，它被视为缺失。You code should work. Certainly
nameFirstisnull, hence it counts as missing as far as FreeMarker is concerned.好的，问题解决了！
我们从 JSON 代码填充记录，这意味着 JSON 尝试根据 JSON 符号（大写、小写等）中定义属性的方式使用 setter。
由于 setter 名称不符合 JSON 名称（即 setNameFirst 作为 setter 名称与 JSON 中的 name_first），因此对象未初始化，并且 FreeMarker 发出错误。
当我没有看到任何错误时，我在 getter 中设置了一个硬编码值，以消除对象为空的选项 - 它让我找到了解决方案。
感谢您的聆听:)
OK, Problem solved!
We we're populating the record from JSON code, meaning JSON was trying to use a setter in accordance to the way properties were defined in the JSON notation (upper case, lower case, etc).
Since the setter name didn't comply with the JSON name (i.e. setNameFirst as the setter name vs. name_first in the JSON) the object was not initialized and the FreeMarker issued an error.
I set a hard coded value in the getter to eliminate the option of the object being null, when I didn't see any error - it let me to the solution.
Thank for listening :)