Java tutorial
package com.thinkbiganalytics.spring; /*- * #%L * kylo-ui-controller * %% * Copyright (C) 2017 ThinkBig Analytics * %% * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. * #L% */ import com.google.common.collect.Lists; import org.apache.commons.io.IOUtils; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.core.io.Resource; import org.springframework.core.io.ResourceLoader; import org.springframework.core.io.support.ResourcePatternUtils; import java.io.IOException; import java.io.InputStream; import java.nio.charset.Charset; import java.util.Collections; import java.util.List; import java.util.Objects; import java.util.stream.Collectors; public class FileResourceService { private static Logger log = LoggerFactory.getLogger(FileResourceService.class); @Autowired private ResourceLoader resourceLoader; public String resourceAsString(Resource resource) { try { if (resource != null) { InputStream is = resource.getInputStream(); return IOUtils.toString(is, Charset.defaultCharset()); } } catch (IOException e) { log.error("Unable to load file {} ", resource.getFilename(), e); } return null; } public String getResourceAsString(String resourceLocation) { return loadResourceAsString(resourceLocation); } public Resource getResource(String resource) { return resourceLoader.getResource(resource); } /** * Return a resourcs/file as a string * * @param resourceLocation a file location string * @return the contents of the file/resource as a string */ public String loadResourceAsString(String resourceLocation) { Resource resource = resourceLoader.getResource(resourceLocation); return resourceAsString(resource); } public Resource[] loadResources(String pattern) throws IOException { return ResourcePatternUtils.getResourcePatternResolver(resourceLoader).getResources(pattern); } public List<String> loadResourcesAsString(String pattern) { try { Resource[] resources = loadResources(pattern); if (resources != null) { return Lists.newArrayList(resources).stream().map(resource -> resourceAsString(resource)) .filter(Objects::nonNull).collect(Collectors.toList()); } } catch (Exception e) { log.error("unable to load resources matching the pattern {} ", pattern, e); } return Collections.emptyList(); } public void loadResources(String pattern, LoadResourceCallback callback) { try { Resource[] resources = loadResources(pattern); if (resources != null) { Lists.newArrayList(resources).stream().forEach(resource -> { try { callback.execute(resource); } catch (Exception e) { log.error("Unable to load resource ", resource.getFilename(), e); } }); } } catch (Exception e) { log.error("unable to load resources matching the pattern {} ", pattern, e); } } }