Customizing WebDataBinder initialization 

To customize request parameter binding with PropertyEditors, etc. via Spring's WebDataBinder, you can either use @InitBinder-annotated methods within your controller or externalize your configuration by providing a custom WebBindingInitializer. 


Customizing data binding with @InitBinder 

Annotating controller methods with @InitBinder allows you to configure web data binding directly within your controller class. @InitBinder identifies methods which initialize the WebDataBinder which will be used for populating command and form object arguments of annotated handler methods. 

Such init-binder methods support all arguments that @RequestMapping supports, except for command/form objects and corresponding validation result objects. Init-binder methods must not have a return value. Thus, they are usually declared as void. Typical arguments include WebDataBinder in combination with WebRequest or java.util.Locale, allowing code to register context-specific editors. 

The following example demonstrates the use of @InitBinder for configuring a CustomDateEditor for all java.util.Date form properties. 



Java代码  ​​@InitBinder_java代码​​


  2. @Controller  
  3. public class MyFormController {  
  4.   
  5.     @InitBinder  
  6.     public void initBinder(WebDataBinder binder) {  
  7.         SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");  
  8.         dateFormat.setLenient(false);  
  9.         binder.registerCustomEditor(Date.class, new CustomDateEditor(dateFormat, false));  
  10.     }  
  11.   
  12.     // ...  
  13. }  


WebDataBinder是用来绑定请求参数到指定的属性编辑器，可以继承WebBindingInitializer来实现一个全部controller共享的dataBiner 



Java代码  ​​@InitBinder_java代码​​


  2. @Component  
  3. public class CommonBindingInitializer implements WebBindingInitializer {  
  4.   
  5.     public void initBinder(WebDataBinder binder, WebRequest request) {  
  6.         SimpleDateFormat dateFormat = new SimpleDateFormat(ERPUtil.ISO_DATE_MASK);  
  7.         dateFormat.setLenient(false);  
  8.         binder.registerCustomEditor(Date.class, new CustomDateEditor(dateFormat, true));  
  9.         binder.registerCustomEditor(String.class, new StringTrimmerEditor(false));  
  10.     }  
  11. }  


也可以在某个单独的contorller里定义一个dataBinder，使用@InitBinder注解就可以实现 


PS：WebDataBinder是用来绑定请求参数到指定的属性编辑器.由于前台传到controller里的值是String类型的，当往Model里Set这个值的时候，如果set的这个属性是个对象，Spring就会去找到对应的EDITOR进行转换，然后再SET进去