private void parseParts(boolean explicit) {
  //...
  MultipartConfigElement mce = this.getWrapper().getMultipartConfigElement();
  //...
  // 讀取MultipartConfigElement對(duì)象的location屬性
  String locationStr = mce.getLocation();
  File location;
  if (locationStr != null && locationStr.length() != 0) {
    location = new File(locationStr);
    if (!location.isAbsolute()) {
      location = (new File((File)context.getServletContext().getAttribute("javax.servlet.context.tempdir"), locationStr)).getAbsoluteFile();
    }
  } else {
    // 如果location屬性值為空，則讀取Servlet上下文對(duì)象的屬性“javax.servlet.context.tempdir”值（如：/tmp/tomcat.6574404581312272268.18333/work/Tomcat/localhost/ROOT）
    location = (File)context.getServletContext().getAttribute("javax.servlet.context.tempdir");
  }
  //...
}

spring.servlet.multipart.location=/data/tmp

# MULTIPART (MultipartProperties)
spring.servlet.multipart.enabled=true # Whether to enable support of multipart uploads.
spring.servlet.multipart.file-size-threshold=0B # Threshold after which files are written to disk.
spring.servlet.multipart.location= # Intermediate location of uploaded files.
spring.servlet.multipart.max-file-size=1MB # Max file size.
spring.servlet.multipart.max-request-size=10MB # Max request size.
spring.servlet.multipart.resolve-lazily=false # Whether to resolve the multipart request lazily at the time of file or parameter access.

/**
 * 配置上傳文件臨時(shí)目錄
 * @return
 */
@Bean
public MultipartConfigElement multipartConfigElement() {
  MultipartConfigFactory factory = new MultipartConfigFactory();
  // tmp.dir參數(shù)在啟動(dòng)腳本中設(shè)置
  String path = System.getProperty("tmp.dir");
  if(path == null || "".equals(path.trim())) {
    path = System.getProperty("user.dir");
  }
  String location = path + "/tmp";
  File tmpFile = new File(location);
  // 如果臨時(shí)目錄不存在則創(chuàng)建
  if (!tmpFile.exists()) {
    tmpFile.mkdirs();
  }
  // 明確指定上傳文件的臨時(shí)目錄
  factory.setLocation(location);
  return factory.createMultipartConfig();
}