在开发当中经常遇到过这种情况，Controller方法中接收参数的是Integer，或Double类型时，客户端经常会传字符串null或(null)，这时服务器就会抛出异常。

本来是前端不小心导致的问题，我们可不想背锅。

想直接执行方法，如下：

public class MyWebBindingInitializer extends ConfigurableWebBindingInitializer {

    @Override
    public void initBinder(WebDataBinder binder, WebRequest request) {
        super.initBinder(binder, request);
        binder.registerCustomEditor(Number.class, new MyCustomNumberEditor(Number.class, true));
    }


}

下面这段代码是我重写springframework中CustomNumberEditor类，在关键方法增加是否是数字的验证。

import org.springframework.util.NumberUtils;
import org.springframework.util.StringUtils;

import java.beans.PropertyEditorSupport;
import java.text.NumberFormat;

public class MyCustomNumberEditor extends PropertyEditorSupport {
    private final Class<? extends Number> numberClass;
    private final NumberFormat numberFormat;
    private final boolean allowEmpty;

    public MyCustomNumberEditor(Class<? extends Number> numberClass, boolean allowEmpty) throws IllegalArgumentException {
        this(numberClass, (NumberFormat) null, allowEmpty);
    }

    public MyCustomNumberEditor(Class<? extends Number> numberClass, NumberFormat numberFormat, boolean allowEmpty) throws IllegalArgumentException {
        if (numberClass != null && Number.class.isAssignableFrom(numberClass)) {
            this.numberClass = numberClass;
            this.numberFormat = numberFormat;
            this.allowEmpty = allowEmpty;
        } else {
            throw new IllegalArgumentException("Property class must be a subclass of Number");
        }
    }

    public void setAsText(String text) throws IllegalArgumentException {
        if (this.allowEmpty && !StringUtils.hasText(text)) {
            this.setValue((Object) null);
        } else if (!org.apache.commons.lang3.math.NumberUtils.isNumber(text)) {
            this.setValue((Object) null);//如果不是数字类型
        } else if (this.numberFormat != null) {
            this.setValue(NumberUtils.parseNumber(text, this.numberClass, this.numberFormat));
        } else {
            this.setValue(NumberUtils.parseNumber(text, this.numberClass));
        }

    }

    public void setValue(Object value) {
        if (value instanceof Number) {
            super.setValue(NumberUtils.convertNumberToTargetClass((Number) value, this.numberClass));
        } else {
            super.setValue(value);
        }

    }

    public String getAsText() {
        Object value = this.getValue();
        if (value == null) {
            return "";
        } else {
            return this.numberFormat != null ? this.numberFormat.format(value) : value.toString();
        }
    }

}

配置文件：

<bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter">
        <property name="webBindingInitializer">
            <bean class="com.ssb.web.common.MyWebBindingInitializer">
                <property name="conversionService" ref="conversionService"/>
            </bean>
        </property>
...
</bean>