下载文件，文件名在portlet中不起作用 [英] Download file, filename doesn't work in portlet

问题描述

我在HttpServletResponse标头中设置了文件名，但下载时却没有此文件名

FileInputStream fis = new FileInputStream(fileDocumento);
PortletResponse portletResponse=(PortletResponse) FacesContext.getCurrentInstance().getExternalContext().getResponse();
HttpServletResponse res = PortalUtil.getHttpServletResponse(portletResponse);       

res.setHeader("Content-Disposition", "attachment; filename=schedaObiettivoTAC_.docx");
res.setHeader("Content-Transfer-Encoding", "binary");
res.setContentType("application/vnd.openxmlformats-officedocument.wordprocessingml.document");
res.flushBuffer();

OutputStream out=res.getOutputStream();
out.write(IOUtils.toByteArray(fis));
out.close();

fis.close();

解决方案

您不应使用HttpServletResponse.相反，您应该创建一个自定义 Resource 和 ResourceHandler :

CustomResourceHandler.java :

public final class CustomResourceHandler extends ResourceHandlerWrapper {

    // Public Constants
    public static final String LIBRARY_NAME = "exampleLib";
    public static final String RESOURCE_NAME = "exampleName";

    // Private Data Members
    private ResourceHandler wrappedResourceHandler;

    public CustomResourceHandler(ResourceHandler resourceHandler) {
        this.wrappedResourceHandler = resourceHandler;
    }

    @Override
    public Resource createResource(String resourceName, String libraryName) {

        if (LIBRARY_NAME.equals(libraryName)) {

            if (RESOURCE_NAME.equals(resourceName)) {
                return new CustomResource(libraryName, resourceName,
                    "exampleFileName.txt", "Example Content");
            }
            else {
                return super.createResource(resourceName, libraryName);
            }
        }
        else {
            return super.createResource(resourceName, libraryName);
        }
    }

    @Override
    public ResourceHandler getWrapped() {
        return wrappedResourceHandler;
    }

    @Override
    public boolean libraryExists(String libraryName) {

        if (LIBRARY_NAME.equals(libraryName)) {
            return true;
        }
        else {
            return super.libraryExists(libraryName);
        }
    }

    /* package-private */ static final class CustomResource extends Resource {

        private final String content;
        private final Map<String, String> responseHeaders;
        private final String requestPath;
        private final URL url;

        public CustomResource(String libraryName, String resourceName,
            String fileName, String content) {

            super.setLibraryName(libraryName);
            super.setResourceName(resourceName);
            super.setContentType("text/plain");

            Map<String, String> responseHeaders = new HashMap<String, String>();
            responseHeaders.put("Content-Disposition",
                "attachment; filename=" + fileName + ";");

            this.responseHeaders = Collections.unmodifiableMap(responseHeaders);

            StringBuilder sb = new StringBuilder();
            sb.append(ResourceHandler.RESOURCE_IDENTIFIER);
            sb.append("/");
            sb.append(super.getResourceName());
            sb.append("?ln=");
            sb.append(super.getLibraryName());
            this.requestPath = sb.toString();

            URL url;

            try {

                FacesContext facesContext = FacesContext.getCurrentInstance();
                ExternalContext externalContext = facesContext.getExternalContext();
                url = new URL(externalContext.encodeResourceURL(this.requestPath));
            }
            catch (MalformedURLException e) {
                url = null;
            }

            this.url = url;
            this.content = content;
        }

        @Override
        public InputStream getInputStream() throws IOException {
            return new ByteArrayInputStream(
                content.getBytes(StandardCharsets.UTF_8));
        }

        @Override
        public String getRequestPath() {
            return requestPath;
        }

        @Override
        public Map<String, String> getResponseHeaders() {
            return responseHeaders;
        }

        @Override
        public URL getURL() {
            return url;
        }

        @Override
        public boolean userAgentNeedsUpdate(FacesContext facesContext) {

            // Return false if the content cannot change dynamically.
            return true;
        }
    }
}

WEB-INF/faces-config.xml :

<?xml version="1.0" encoding="UTF-8"?>
<faces-config version="2.2" 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-facesconfig_2_2.xsd">

    <application>
        <!-- ... -->
        <resource-handler>custom.resource.handler.CustomResourceHandler</resource-handler>
    </application>
<!-- ... -->
</faces-config>

下面是一些下载资源的示例代码:

<h:outputLink target="_blank" value="#{bean.getDownloadURL(facesContext)}">
    <h:outputText value="download" />
</h:outputLink>

---

public String getDownloadURL(FacesContext facesContext) {

    return facesContext.getApplication().getResourceHandler()
            .createResource(CustomResourceHandler.RESOURCE_NAME,
                CustomResourceHandler.LIBRARY_NAME)
            .getURL().toString();
}

您还可以查看

解决方案

You should not use the HttpServletResponse. Instead you should create a custom Resource and ResourceHandler:

CustomResourceHandler.java:

public final class CustomResourceHandler extends ResourceHandlerWrapper {

    // Public Constants
    public static final String LIBRARY_NAME = "exampleLib";
    public static final String RESOURCE_NAME = "exampleName";

    // Private Data Members
    private ResourceHandler wrappedResourceHandler;

    public CustomResourceHandler(ResourceHandler resourceHandler) {
        this.wrappedResourceHandler = resourceHandler;
    }

    @Override
    public Resource createResource(String resourceName, String libraryName) {

        if (LIBRARY_NAME.equals(libraryName)) {

            if (RESOURCE_NAME.equals(resourceName)) {
                return new CustomResource(libraryName, resourceName,
                    "exampleFileName.txt", "Example Content");
            }
            else {
                return super.createResource(resourceName, libraryName);
            }
        }
        else {
            return super.createResource(resourceName, libraryName);
        }
    }

    @Override
    public ResourceHandler getWrapped() {
        return wrappedResourceHandler;
    }

    @Override
    public boolean libraryExists(String libraryName) {

        if (LIBRARY_NAME.equals(libraryName)) {
            return true;
        }
        else {
            return super.libraryExists(libraryName);
        }
    }

    /* package-private */ static final class CustomResource extends Resource {

        private final String content;
        private final Map<String, String> responseHeaders;
        private final String requestPath;
        private final URL url;

        public CustomResource(String libraryName, String resourceName,
            String fileName, String content) {

            super.setLibraryName(libraryName);
            super.setResourceName(resourceName);
            super.setContentType("text/plain");

            Map<String, String> responseHeaders = new HashMap<String, String>();
            responseHeaders.put("Content-Disposition",
                "attachment; filename=" + fileName + ";");

            this.responseHeaders = Collections.unmodifiableMap(responseHeaders);

            StringBuilder sb = new StringBuilder();
            sb.append(ResourceHandler.RESOURCE_IDENTIFIER);
            sb.append("/");
            sb.append(super.getResourceName());
            sb.append("?ln=");
            sb.append(super.getLibraryName());
            this.requestPath = sb.toString();

            URL url;

            try {

                FacesContext facesContext = FacesContext.getCurrentInstance();
                ExternalContext externalContext = facesContext.getExternalContext();
                url = new URL(externalContext.encodeResourceURL(this.requestPath));
            }
            catch (MalformedURLException e) {
                url = null;
            }

            this.url = url;
            this.content = content;
        }

        @Override
        public InputStream getInputStream() throws IOException {
            return new ByteArrayInputStream(
                content.getBytes(StandardCharsets.UTF_8));
        }

        @Override
        public String getRequestPath() {
            return requestPath;
        }

        @Override
        public Map<String, String> getResponseHeaders() {
            return responseHeaders;
        }

        @Override
        public URL getURL() {
            return url;
        }

        @Override
        public boolean userAgentNeedsUpdate(FacesContext facesContext) {

            // Return false if the content cannot change dynamically.
            return true;
        }
    }
}

WEB-INF/faces-config.xml:

<?xml version="1.0" encoding="UTF-8"?>
<faces-config version="2.2" 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-facesconfig_2_2.xsd">

    <application>
        <!-- ... -->
        <resource-handler>custom.resource.handler.CustomResourceHandler</resource-handler>
    </application>
<!-- ... -->
</faces-config>

Here's some example code for downloading the resource:

<h:outputLink target="_blank" value="#{bean.getDownloadURL(facesContext)}">
    <h:outputText value="download" />
</h:outputLink>

---

public String getDownloadURL(FacesContext facesContext) {

    return facesContext.getApplication().getResourceHandler()
            .createResource(CustomResourceHandler.RESOURCE_NAME,
                CustomResourceHandler.LIBRARY_NAME)
            .getURL().toString();
}

You can also look at the Liferay Faces JSF Export PDF for a full portlet example to download/export a file.

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