<html:file>上传文件标签

<html:errors/>
<html:form action="upload.do" method="POST" enctype="multipart/form-data">
<html:file property="file"/><br>
<html:submit property="submit" value="Submit"/><br>
</html:form>

package upload;

import javax.servlet.http.HttpServletRequest;

import org.apache.struts.action.*;
import org.apache.struts.upload.FormFile;

public class FileForm extends ActionForm {
    private FormFile file;
    public FormFile getFile() {
        return file;
    }
    public void setFile(FormFile file) {
        this.file = file;
    }
   public ActionErrors validate(ActionMapping actionMapping,
                                 HttpServletRequest httpServletRequest) {
        /** 先验证是否有文件，再验证文件格式.*/
        ActionErrors errors = new ActionErrors();
        if (file == null || file.equals("")) {
            errors.add("ext", new ActionMessage("ext"));
            return errors;
        }
        String fullname = file.getFileName();
        String ext = fullname.substring(fullname.indexOf("."), fullname.length());
        if (!(ext.equalsIgnoreCase(".jpg") || ext.equalsIgnoreCase(".gif") ||
              ext.equalsIgnoreCase(".png"))) {
            System.out.println("封装错误信息");
            errors.add("ext", new ActionMessage("ext"));
        }
        return errors;
    }
    public void reset(ActionMapping actionMapping,
                      HttpServletRequest servletRequest) {
    }
}

package upload;

import org.apache.struts.action.ActionMapping;
import org.apache.struts.action.ActionForm;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.Action;
import org.apache.struts.upload.FormFile;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.FileOutputStream;

public class UploadAction extends Action {
    public ActionForward execute(ActionMapping mapping, ActionForm form,
                                 HttpServletRequest request,
                                 HttpServletResponse response) throws
            FileNotFoundException, IOException {

        String dir = servlet.getServletContext().getRealPath(""); //根目录
        FileForm fileForm = (FileForm) form;
        FormFile file = fileForm.getFile();
        String fname = file.getFileName();
        InputStream streamIn = file.getInputStream(); //输入流
        OutputStream streamOut = new FileOutputStream(dir + "/" + fname);
        int bytesRead = 0;
        byte[] buffer = new byte[8192];
        while ((bytesRead = streamIn.read(buffer, 0, 8192)) != -1) {
            streamOut.write(buffer, 0, bytesRead);
        }
        streamIn.close();
        streamOut.close();
        return new ActionForward("/success.jsp");
    }
}