字符串從空到空-將表單字段空到空-Spring編輯器-StringTrimmerEditor

Question

我讀了幾篇文章，並嘗試以相同的方式實現，但是不知何故我遇到了錯誤。 我想通過XML based configuration來實現。

兩種方式

基於注釋-工作正常

@ControllerAdvice
@Controller
public class AppBindingInitializer {

    @InitBinder
    public void initBinder(WebDataBinder binder) {
        binder.registerCustomEditor(String.class, new StringTrimmerEditor(true));
    }

}

基於XML-出現錯誤

<bean id="coreCustomEditors" class="org.springframework.beans.factory.config.CustomEditorConfigurer">
     <property name="customEditors">
        <map>
            <entry key="java.lang.String">
                <bean class="org.springframework.beans.propertyeditors.StringTrimmerEditor">
                    <constructor-arg name="emptyAsNull" value="true" />
                </bean>
            </entry>
        </map>
    </property>
 </bean>

例外

Caused by: org.springframework.beans.TypeMismatchException: Failed to convert property value of type 'java.util.LinkedHashMap' to required type 'java.util.Map' for property 'customEditors'; nested exc
eption is java.lang.IllegalArgumentException: Cannot convert value of type [org.springframework.beans.propertyeditors.StringTrimmerEditor] to required type [java.lang.Class] for property 'customEditor
s[java.lang.String]': PropertyEditor [org.springframework.beans.propertyeditors.ClassEditor] returned inappropriate value of type [org.springframework.beans.propertyeditors.StringTrimmerEditor]
        at org.springframework.beans.BeanWrapperImpl.convertIfNecessary(BeanWrapperImpl.java:479)
        at org.springframework.beans.BeanWrapperImpl.convertForProperty(BeanWrapperImpl.java:511)
        at org.springframework.beans.BeanWrapperImpl.convertForProperty(BeanWrapperImpl.java:505)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.convertForProperty(AbstractAutowireCapableBeanFactory.java:1502)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1461)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1197)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:537)
        ... 53 more
Caused by: java.lang.IllegalArgumentException: Cannot convert value of type [org.springframework.beans.propertyeditors.StringTrimmerEditor] to required type [java.lang.Class] for property 'customEdito
rs[java.lang.String]': PropertyEditor [org.springframework.beans.propertyeditors.ClassEditor] returned inappropriate value of type [org.springframework.beans.propertyeditors.StringTrimmerEditor]
        at org.springframework.beans.TypeConverterDelegate.convertIfNecessary(TypeConverterDelegate.java:263)
        at org.springframework.beans.TypeConverterDelegate.convertToTypedMap(TypeConverterDelegate.java:623)
        at org.springframework.beans.TypeConverterDelegate.convertIfNecessary(TypeConverterDelegate.java:208)
        at org.springframework.beans.BeanWrapperImpl.convertIfNecessary(BeanWrapperImpl.java:459)

Answer 1

您必須指定一個類名作為值，而不是一個bean（如消息中所述），如下所示：

<bean id="coreCustomEditors" class="org.springframework.beans.factory.config.CustomEditorConfigurer">
     <property name="customEditors">
         <map>
             <entry key="java.lang.String" value="your.package.EmptyAsNullStringTrimmerEditor"/>
         </map>
    </property>
</bean>

與EmptyAsNullStringTrimmerEditor是：

package your.package;

public class EmptyAsNullStringTrimmerEditor extends StringTrimmerEditor {
    public YourClass() { super(true); }
}

參見CustomEditorConfigurer javadoc