java – 防止在页面加载时将后缀添加到资源中

<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>*.xhtml</url-pattern>
</servlet-mapping>
<servlet-mapping>
    <servlet-name>Faces Servlet</servlet-name>
    <url-pattern>/javax.faces.resource/*</url-pattern>
</servlet-mapping>

WARNING: StandardWrapperValve[Faces Servlet]: PWC1406: Servlet.service() for servlet Faces Servlet threw exception
java.lang.NullPointerException
    at com.sun.faces.application.ApplicationImpl.createComponent(ApplicationImpl.java:975)
    at com.sun.faces.facelets.tag.jsf.CompositeComponentTagHandler.createComponent(CompositeComponentTagHandler.java:162)
    at com.sun.faces.facelets.tag.jsf.ComponentTagHandlerDelegateImpl.createComponent(ComponentTagHandlerDelegateImpl.java:494)
    at com.sun.faces.facelets.tag.jsf.ComponentTagHandlerDelegateImpl.apply(ComponentTagHandlerDelegateImpl.java:169)
...

String packageName = componentResource.getLibraryName();
String className = componentResource.getResourceName();
className = packageName + '.' + className.substring(0,className.lastIndexOf('.'));

这可以在 createResource()中返回一个 Resource,然后在 Resource#getRequestPath()返回一个“未映射的”URL的自定义 ResourceHandler.您只需要将默认的JSF资源前缀/javax.faces.resource/*添加到< url-pattern&gt ; FacesServlet映射的列表,以使其被触发. 此外,您需要覆盖 isResourceRequest()以检查URL是否以JSF资源前缀开头,也可以使用 handleResourceRequest()来定位和流式传输正确的资源.

所有这一切,这应该做：

public class UnmappedResourceHandler extends ResourceHandlerWrapper {

    private ResourceHandler wrapped;

    public UnmappedResourceHandler(ResourceHandler wrapped) {
        this.wrapped = wrapped;
    }

    @Override
    public Resource createResource(final String resourceName,final String libraryName) {
        final Resource resource = super.createResource(resourceName,libraryName);

        if (resource == null) {
            return null;
        }

        return new ResourceWrapper() {

            @Override
            public String getRequestPath() {
                ExternalContext externalContext = FacesContext.getCurrentInstance().getExternalContext();
                String mapping = externalContext.getRequestServletPath();

                if (externalContext.getRequestPathInfo() == null) {
                    mapping = mapping.substring(mapping.lastIndexOf('.'));
                }

                String path = super.getRequestPath();

                if (mapping.charAt(0) == '/') {
                    return path.replaceFirst(mapping,"");
                }
                else if (path.contains("?")) {
                    return path.replace(mapping + "?","?");
                }
                else {
                    return path.substring(0,path.length() - mapping.length());
                }
            }

            @Override // Necessary because this is missing in ResourceWrapper (will be fixed in JSF 2.2).
            public String getResourceName() {
                return resource.getResourceName();
            }

            @Override // Necessary because this is missing in ResourceWrapper (will be fixed in JSF 2.2).
            public String getLibraryName() {
                return resource.getLibraryName();
            }

            @Override // Necessary because this is missing in ResourceWrapper (will be fixed in JSF 2.2).
            public String getContentType() {
                return resource.getContentType();
            }

            @Override
            public Resource getWrapped() {
                return resource;
            }
        };
    }

    @Override
    public boolean isResourceRequest(FacesContext context) {
        return ResourceHandler.RESOURCE_IDENTIFIER.equals(context.getExternalContext().getRequestServletPath());
    }

    @Override
    public void handleResourceRequest(FacesContext context) throws IOException {
        ExternalContext externalContext = context.getExternalContext();
        String resourceName = externalContext.getRequestPathInfo();
        String libraryName = externalContext.getRequestParameterMap().get("ln");
        Resource resource = context.getApplication().getResourceHandler().createResource(resourceName,libraryName);

        if (resource == null) {
            super.handleResourceRequest(context);
            return;
        }

        if (!resource.userAgentNeedsUpdate(context)) {
            externalContext.setResponseStatus(HttpServletResponse.SC_NOT_MODIFIED);
            return;
        }

        externalContext.setResponseContentType(resource.getContentType());

        for (Entry<String,String> header : resource.getResponseHeaders().entrySet()) {
            externalContext.setResponseHeader(header.getKey(),header.getValue());
        }

        ReadableByteChannel input = null;
        WritableByteChannel output = null;

        try {
            input = Channels.newChannel(resource.getInputStream());
            output = Channels.newChannel(externalContext.getResponSEOutputStream());

            for (ByteBuffer buffer = ByteBuffer.allocateDirect(10240); input.read(buffer) != -1; buffer.clear()) {
                output.write((ByteBuffer) buffer.flip());
            }
        }
        finally {
            if (output != null) try { output.close(); } catch (IOException ignore) {}
            if (input != null) try { input.close(); } catch (IOException ignore) {}
        }
    }

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

}

在faces-config.xml中注册如下：

<application>
    <resource-handler>com.example.UnmappedResourceHandler</resource-handler>
</application>

使用ResourceHandler.RESOURCE_IDENTIFIER扩展FacesServlet URL模式：

<servlet-mapping>
    <servlet-name>facesServlet</servlet-name>
    <url-pattern>*.xhtml</url-pattern>
    <url-pattern>/javax.faces.resource/*</url-pattern>
</servlet-mapping>