spring mvc MultipartFile 上传文件 当文件较小时(10k) ，无法上传成功 。

<!-- SpringMVC上传文件时，需要配置MultipartResolver处理器 -->
    <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
        <property name="defaultEncoding" value="UTF-8"/>
        <!-- 指定所上传文件的总大小不能超过200KB。注意maxUploadSize属性的限制不是针对单个文件，而是所有文件的容量之和 -->
        <property name="maxUploadSize" value="1024000"/>
        <property name="fileItemFactory.sizeThreshold" value="0"></property>
    </bean>

查看该类源码

有一段说明文档

* <p>Provides "maxUploadSize", "maxInMemorySize" and "defaultEncoding" settings as
* bean properties (inherited from {@link CommonsFileUploadSupport}). See corresponding
* ServletFileUpload / DiskFileItemFactory properties ("sizeMax", "sizeThreshold",
* "headerEncoding") for details in terms of defaults and accepted values.

进入 CommonsFileUploadSupport

public abstract class CommonsFileUploadSupport {

	protected final Log logger = LogFactory.getLog(getClass());

	private final DiskFileItemFactory fileItemFactory;

	private final FileUpload fileUpload;

	private boolean uploadTempDirSpecified = false;

　　进入

DiskFileItemFactory  类 
看到  

/**
     * The threshold above which uploads will be stored on disk.
     */
    private int sizeThreshold = DEFAULT_SIZE_THRESHOLD;//DEFAULT_SIZE_THRESHOLD=10240就是10k

设置下这个参数即可。