java form表单接收空字符串,有没有简单的方法来将空的Java / Spring表单输入变成空字符串？...

旧城等待， 2022-10-04 12:51 4阅读 0赞

![Image 1][]

Is there an easy way to turn empty form input into null strings in java? I'm using spring mvc and SimpleJdbcInsert to insert the object into a MySQL database. I'd like to set the blank input to NULL in the database rather than ''. I have quite a few fields, and I'm hoping for a way to do this without manually checking every value.

Thanks!

edit - So I'm an idiot. Several errors combined on my part led me to believe the correct answers below were not correct. I'd written a propertyEditorSupport like this:

class StringEditor extends PropertyEditorSupport \{

public void setAsText(String text) \{

String value = text.trim();

if ("" == value) \{

setValue(null);

else \{

setValue(value);

Two problems - first, no getAsText, so my form was getting populated with "null" strings! 2nd, my equality check is C++, not java. When I tried the recommended setter, I just reloaded the post, which already contained the "null" strings. Once I cleaned all that up, everything started working. Thanks for the help, and sorry for my "operator error"!

Brett

解决方案

The class you're looking for is:

org.springframework.beans.propertyeditors.StringTrimmerEditor

If you construct it with a true it will convert empty/whitespace strings to null. How to get it registered onto the binder depends on if you want it to be the default or only apply to certain views.

e.g., on a single controller you can just add

@InitBinder

public void initBinder(WebDataBinder binder) \{

binder.registerCustomEditor(String.class, new StringTrimmerEditor(true));

[Image 1]: