Java ServletFileUpload.isMultipartContent（请求）返回false

从jsp页面中选择多个文件并在Servlet ServletFileUpload中提交表单。isMultipartContent（请求）返回false

代码如下：

JSP代码：

<form action="multiFileSelection" enctype="multipart/form-data">
    <input type="file" id="selectedFile" multiple/>
    <input type="submit" value="Submit"/>

</form>

---

它现在起作用了。我在@WebServlet（“/UploadFileServlet”）下面添加了@MultipartConfig注释

import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Iterator;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.tomcat.util.http.fileupload.FileItem;
import org.apache.tomcat.util.http.fileupload.FileItemFactory;
import org.apache.tomcat.util.http.fileupload.FileUploadException;
import org.apache.tomcat.util.http.fileupload.disk.DiskFileItemFactory;
import org.apache.tomcat.util.http.fileupload.servlet.ServletFileUpload;
import org.apache.tomcat.util.http.fileupload.servlet.ServletRequestContext;

@WebServlet("/multiFileSelection")
public class multiFileSelection extends HttpServlet {
    private static final long serialVersionUID = 1L;

public multiFileSelection() {
    super();
}

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    boolean isMultipart = ServletFileUpload.isMultipartContent(request); 
    System.out.println("Multiple Selction returns : " + isMultipart);
}

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    doGet(request, response);
}

}