将java.io.File转换为org.apache.struts.upload.FormFile

Question

I am in a situation where i have to cast a java.io.File object to Struts org.apache.struts.upload.FormFile object. The type conversion is resulting in error. Can any one suggest a way or a code snippet that i can use to do above operation. Any advice would be helpful.

Answer 1

I implemented the above sugesstion and it worked for me. It dynamically converted a java File to a FormFile. U also have to set the file name & size while converting it dynamically.

public String getFileName() {
    return this.file.getName();
}

public int getFileSize() {
    return (int) this.file.length();
}

while invoking this wrapper this you have to pass the file location & can directly assign it to the FormFile.

FileWrapper fileWr = new FileWrapper(new File("X://file/file.xlsx"));
FormFile file = fileWr;
String fileName = file.getFileName();

Answer 2

You can't directly cast File to FormFile because File does't implement FormFile interface. But you can create wrapper for File object and implement this interface. Something like: import org.apache.struts.upload.FormFile;

import java.io.*;

public class FileWrapper implements FormFile {
    private final File file;

    public FileWrapper(File file) {
        this.file = file;
    }

    @Override
    public String getContentType() {
    }

    @Override
    public void setContentType(String s) {
    }

    @Override
    public int getFileSize() {
    }

    @Override
    public void setFileSize(int i) {
    }

    @Override
    public String getFileName() {
    }

    @Override
    public void setFileName(String s) {
    }

    @Override
    public byte[] getFileData() throws IOException {
        byte[] buffer = new byte[(int) file.length()];
        FileInputStream fileInputStream = new FileInputStream(file);
        fileInputStream.read(buffer);
        fileInputStream.close();
        return buffer;
    }

    @Override
    public InputStream getInputStream() throws IOException {
        return new FileInputStream(file);
    }

    @Override
    public void destroy() {
        if (!file.delete()) {
            throw new RuntimeException("File " + file.getName() + " can't be deleted");
        }
    }
}

Here I haven't implemented all methods because implementation depends on your requirements.