web.config新增以下配置

<configuration>
  <system.web>
    <httpRuntime maxRequestLength="2048576000" executionTimeout="48000" />
  </system.web>
  <system.webServer>
    <security>
      <requestFiltering>
        <requestLimits maxAllowedContentLength="1048576000"></requestLimits>
      </requestFiltering>
    </security>
  </system.webServer>
</configuration>