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jsf - 为什么 UploadedFile 为空？

转载 作者：行者123 更新时间：2023-12-03 23:57:33 25 4
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这个问题在这里已经有了答案:





How to use PrimeFaces p:fileUpload? Listener method is never invoked or UploadedFile is null / throws an error / not usable

(11 个回答)


4年前关闭。




我正在使用 JSF 2.2 开发 Java Web 应用程序和 Primefaces .我希望用户可以上传单个文件；为此，我使用了 Primefaces 6.0但它不起作用，我刚刚找到了 Primefaces 5.x 的教程(和示例)它也不适用于 Primefaces 5.0 .

我更喜欢和 Primefaces 6.0 一起工作但如果你能帮我一个 Primefaces 5.x版本，没问题。

我的 web.xml 是:

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.1" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd">
    <context-param>
        <param-name>primefaces.THEME</param-name>
        <param-value>bootstrap</param-value>
    </context-param>
    <context-param>
        <param-name>javax.faces.PROJECT_STAGE</param-name>
        <param-value>Development</param-value>
    </context-param>
    <filter>
        <filter-name>primeFacesFileUploadFilter</filter-name>
        <filter-class>org.primefaces.webapp.filter.FileUploadFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>primeFacesFileUploadFilter</filter-name>
        <servlet-name>facesServlet</servlet-name>
    </filter-mapping>
    <context-param>
        <param-name>primefaces.UPLOADER</param-name>
        <param-value>commons</param-value>
    </context-param>

    <servlet>
        <servlet-name>Faces Servlet</servlet-name>
        <servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>Faces Servlet</servlet-name>
        <url-pattern>/faces/*</url-pattern>
    </servlet-mapping>
    <session-config>
        <session-timeout>
            30
        </session-timeout>
    </session-config>
    <welcome-file-list>
        <welcome-file>faces/index.xhtml</welcome-file>
    </welcome-file-list>
</web-app>

我的bean代码是 
import javax.faces.application.FacesMessage;
import javax.faces.bean.ManagedBean;
import javax.faces.bean.RequestScoped;
import javax.faces.context.FacesContext;
import org.primefaces.model.UploadedFile;

@ManagedBean
@RequestScoped
public class ZipBean{

    UploadedFile arch;

    public ZipBean() {
    }

    public void subir() {
        try {
            FacesContext context = FacesContext.getCurrentInstance();
            if (this.arch != null) {
                context.addMessage(null, new FacesMessage(FacesMessage.SEVERITY_FATAL, "PERFECT!","PERFECT!"));
            } else {
                context.addMessage(null, new FacesMessage(FacesMessage.SEVERITY_FATAL, "FILE NULL","FILE NULL"));
            }
        } catch (Exception e) {
            System.out.println(e.toString());
        }
    }

    public UploadedFile getArch() {
        return arch;
    }

    public void setArch(UploadedFile arch) {
        this.arch = arch;
    }

}

我的 xhtml 是: 
<?xml version='1.0' encoding='UTF-8' ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
      xmlns:h="http://xmlns.jcp.org/jsf/html"
      xmlns:p="http://primefaces.org/ui">
    <h:head>
        <title>Facelet Title</title>
    </h:head>
    <h:body>
        <p:growl autoUpdate="true"/>
        <h:form enctype="multipart/form-data">
            <p:fileUpload mode="simple" value="#{zipBean.arch}" />
            <p:commandButton value="Upload" action="#{zipBean.subir}" ajax="false" />
        </h:form>
    </h:body>
</html>

当我上传文件时， p:grow显示消息 FILE IS NULL .

我有下一个 jar图书馆:
  • commons-fileupload-1.3.1.jar
  • commons-io-2.4.jar

    • 谢谢!

    最佳答案

    以下是如何使用 primefaces 5.0 上传文件的示例；并且您不需要 commons-fileupload-1.3.1.jar 和 commons-io-2.4.jar；而且你也不需要改变 web.xml ，并在 h:form 中声明咆哮
    有关更多信息，请参阅此 How to upload file in primefaces

    文件上传 View .java

    import javax.faces.application.FacesMessage;
    import javax.faces.bean.ManagedBean;
    import javax.faces.context.FacesContext;
    import org.primefaces.model.UploadedFile;
    @ManagedBean
    public class FileUploadView {
        private UploadedFile file;
        public UploadedFile getFile() {
            return file;
        }
        public void setFile(UploadedFile file) {
            this.file = file;
        }
        public void upload() {
            if(file.getSize() > 0) {
                FacesMessage message = new FacesMessage("Succesful", file.getFileName() + " is uploaded.");
                FacesContext.getCurrentInstance().addMessage(null, message);
            }
    else{
        FacesMessage message = new FacesMessage("Not Succesful", "file is not uploaded");
                FacesContext.getCurrentInstance().addMessage(null, message);
    }
        }
    }

    基本.xhtml 
    <?xml version='1.0' encoding='UTF-8' ?>
    <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
    <html xmlns="http://www.w3.org/1999/xhtml"
          xmlns:h="http://xmlns.jcp.org/jsf/html"
          xmlns:p="http://primefaces.org/ui">
        <h:head>
            <title>Facelet Title</title>
        </h:head>
        <h:body>
    <h:form enctype="multipart/form-data">
        <p:growl id="messages" showDetail="true" />

        <p:fileUpload value="#{fileUploadView.file}" mode="simple" skinSimple="true"/>

        <p:commandButton value="Submit" ajax="false" actionListener="#{fileUploadView.upload}" />
    </h:form>
      </h:body>
    </html>

    关于jsf - 为什么 UploadedFile 为空？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/41641469/

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