file-upload - 如何限制允许上传的文件数量

Question

如何在 JSF 2 + primefaces 应用程序中限制允许上传的文件数量。primeface 3.3 中有属性“filelimit”，但我使用的是 primefaces 3.4

Answer 1

看起来 fileLimit 选项已在 Issue 3618中删除

正如评论中提到的，在支持 bean 中使用一个计数器，或者丢弃额外的文件，或者添加一个 FacesMessage 来通知用户已达到最大 fileLimit。

代码示例：

@ManagedBean
@ViewScoped
public class FileUploadController {

    private final static int MAX_NUM_FILES = 3;
    private List<UploadedFile> uploadedFiles;
    private int counter = 0;

    @PostConstruct
    public void init() {
        uploadedFiles = new ArrayList<UploadedFile>();
    }


    public void handleFileUpload(FileUploadEvent event) {
        if (counter < MAX_NUM_FILES) {
            uploadedFiles.add(event.getFile());
            FacesMessage msg = new FacesMessage("Succesful", event.getFile().getFileName() + " is uploaded.");
            FacesContext.getCurrentInstance().addMessage(null, msg);
            counter ++;       
        }
        else {
            FacesMessage msg = new FacesMessage(FacesMessage.SEVERITY_ERROR, "File Upload Limit Reached ", event.getFile().getFileName() + " is not uploaded.");
            FacesContext.getCurrentInstance().addMessage(null, msg);
        }

    }
}