jsp - Upload multiple files at once to a Struts2 @Action

Question

I need to upload "1000 files" or "a zip file including all the files" at once using Struts2. (By 1000 Files or a zip file, I mean I need all the files to be uploaded on the system it does not matter if user choose all the 1000 files at once or zip them and upload as a single file, so I am looking for the one which is easier to implement and more efficient)

I have read the following answers but none of them suits the purpose.

Using the following code, when I use a simple List files; it shows name of lists, but when I use List files it does not show any thing and I can not upload the files.

upload.jsp

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>JSP Page</title>
    </head>
    <body>
        <form action="upload" enctype="multipart/form-data" method="post">
            <input name="files" type="file" multiple/>
            <button type="submit"/>
        </form>
    </body>
</html>

upload.java

@Action
public class upload implements Addresses {

    private List <File> files = new ArrayList <File> ();

    public String execute(){

        return "success";
    }
    public upload() {
        System.out.println("in upload 1");

         for(int i=0;i<files.size();i++)
            System.out.println(i + ")" + files.get(i));

        System.out.println("in upload 2");
    }

    public List <File> getFiles() {
        return files;
    }

    public void setFiles(List <File> files) {
        this.files = files;
        for(int i=0;i<files.size();i++)
            System.out.println(i + ")" + files.get(i));
//            File fileToCreate = new File("c:\image", files.get(i).toString());
//            FileUtils.copyFile(files.get(i), fileToCreate);
    }
}

Output

in upload 1
in upload 2

score 9 · Accepted Answer

I suggest you to use Struts Tags instead of plain HTML tags, and to extend ActionSupport (returning its Result constants instead of manually composing the result String, like "result").

That said, this is a tested and working example.

Note: It won't work on old versions of IE, but since you are using HTML5 in your own question, I bet you already know it and you are not targeting old IE.

JSP

<%@page contentType="text/html; charset=UTF-8" %>
<!DOCTYPE html>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>Multiple File Upload Example</title>
    </head>
    <body>
        <s:form action="upload" enctype="multipart/form-data" >
            <s:file name="files" multiple="multiple" />
            <s:submit value="Upload files" />
        </s:form>
    </body>
</html>

Note about the multiple="multiple" part: even if in the official documentation, that attribute for the <s:file /> tag is not defined, since Struts 2.1 it is allowed because of

Dynamic Attributes Allowed: true

this means that it will be drawn on the JSP as-is, without any interference by Struts. This way Struts doens't need to update its Tags each time HTML5 provides a new feature; you could put foo="bar" too in a tag that allows Dynamic Attributes (<s:file />, <s:textarea />, etc), and you will find it in the HTML.

Action

public class Upload extends ActionSupport{

    private List<File> files;
    private List<String> filesContentType;
    private List<String> filesFileName;

    /* GETTERS AND SETTERS */           

    public String execute() throws Exception{
        System.out.print("\n\n---------------------------------------");
        int i=0;
        for (File file : files){
            System.out.print("\nFile ["+i+"] ");
            System.out.print("; name:"         + filesFileName.get(i));
            System.out.print("; contentType: " + filesContentType.get(i));
            System.out.print("; length: "      + file.length());
            i++;
        }
        System.out.println("\n---------------------------------------\n");
        return SUCCESS;
    }

}

Then you may want to set the maximum size of the Request, and the maximum size of each single file, like described here:

Struts.xml - Max multipart size:

<constant name="struts.multipart.maxSize" value="20000000" />

Struts.xml - Max size of a file (globally to a package, or locally to an Action)

<interceptor-ref name="fileUpload">
    <param name="maximumSize">10485760</param>
</interceptor-ref>

score 0 · Accepted Answer

在 JSP 文件中：-

<form action="doUpload" enctype="multipart/form-data" method="post">
      <s:file name="fileUpload" multiple="multiple" label="Pick files" size="30"/>
      <br/>
      <s:submit value="Upload All" />
</form>

在 .java 文件中

 private File fileUpload[];
 private String fileUploadFileName[];
 private String fileUploadContentType[];
 private String saveDirectory;

/** setter and getter for all above variables**/


public String doUpload1()throws Exception{
            for (int i=0; i<fileUpload.length;i++){
                File uploadedFile = fileUpload[i];
                String fileName = fileUploadFileName[i];
                File destFile = new File(saveDirectory + File.separator + fileName);
                try {
                    FileUtils.copyFile(uploadedFile, destFile);
                } catch (IOException ex) {
                    System.out.println("Could not copy file " + fileName);
                    ex.printStackTrace();
                }
            }
        return "success";
    }

这是一个对我有用的，希望对你有用，如果有任何问题，请告诉我。

jsp - Upload multiple files at once to a Struts2 @Action

2 回答 2

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