Struts 2文件上传时没有'Access-Control-Allow-Origin'标头错误

Question

我已按照this链接创建了一个包含Struts2的示例文件上传应用程序。样本效果很好。但是当我尝试使用AJAX上传图像时，我收到以下错误。

XMLHttpRequest cannot load http://localhost:8080/HeeloServer/userImage.action. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:8000' is therefore not allowed access.

这是我的动作类的代码。请注意，我对所有（*）来源使用response.addHeader（）方法。我在其他没有问题的操作中有类似的代码，只有在使用AJAX上传Struts2文件时才会出现此错误。

package actions;

import java.io.File;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.io.FileUtils;
import org.apache.struts2.interceptor.ServletRequestAware;
import org.apache.struts2.interceptor.ServletResponseAware;

import com.opensymphony.xwork2.ActionSupport;

public class FileUploadAction extends ActionSupport implements ServletRequestAware, ServletResponseAware {
    private File userImage;
    private String userImageContentType;
    private String userImageFileName;
    private String email;

    private HttpServletRequest servletRequest;

    public String execute() {
        System.out.println("inside file upload action");
        response.addHeader("Access-Control-Allow-Origin", "*");

        try {
            String filePath = servletRequest.getSession().getServletContext().getRealPath("/") + "photos/";
            System.out.println("Server path: " + filePath);
            System.out.println("Image to be uploaded " + userImageFileName);
            System.out.println("Email" + email);
            File fileToCreate = new File(filePath, this.userImageFileName);
            FileUtils.copyFile(this.userImage, fileToCreate);

        } catch(Exception e) {
            e.printStackTrace();
            addActionError(e.getMessage());
            return INPUT;
        }

        return SUCCESS;

    }

    public File getUserImage() {
        return userImage;
    }

    public void setUserImage(File userImage) {
        this.userImage = userImage;
    }

    public String getUserImageContentType() {
        return userImageContentType;
    }

    public void setUserImageContentType(String userImageContentType) {
        this.userImageContentType = userImageContentType;
    }

    public String getUserImageFileName() {
        return userImageFileName;
    }

    public void setUserImageFileName(String userImageFileName) {
        this.userImageFileName = userImageFileName;
    }

    @Override
    public void setServletRequest(HttpServletRequest servletRequest) {
        this.servletRequest = servletRequest;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }


    public void setServletResponse(HttpServletResponse response){
        this.response = response;
      }

      public HttpServletResponse getServletResponse(){
        return response;
      }




    private HttpServletResponse response;
    public HttpServletResponse getResponse() {
        return response;
    }

    public void setResponse(HttpServletResponse response) {
        this.response = response;
    }






}