Java tutorial
/* * Copyright 2002-2016 the original author or authors. * * 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 * * https://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. */ package org.springframework.beans.propertyeditors; import java.beans.PropertyEditorSupport; import java.io.File; import java.io.IOException; import org.springframework.core.io.Resource; import org.springframework.core.io.ResourceEditor; import org.springframework.util.Assert; import org.springframework.util.ResourceUtils; import org.springframework.util.StringUtils; /** * Editor for {@code java.io.File}, to directly populate a File property * from a Spring resource location. * * <p>Supports Spring-style URL notation: any fully qualified standard URL * ("file:", "http:", etc) and Spring's special "classpath:" pseudo-URL. * * <p><b>NOTE:</b> The behavior of this editor has changed in Spring 2.0. * Previously, it created a File instance directly from a filename. * As of Spring 2.0, it takes a standard Spring resource location as input; * this is consistent with URLEditor and InputStreamEditor now. * * <p><b>NOTE:</b> In Spring 2.5 the following modification was made. * If a file name is specified without a URL prefix or without an absolute path * then we try to locate the file using standard ResourceLoader semantics. * If the file was not found, then a File instance is created assuming the file * name refers to a relative file location. * * @author Juergen Hoeller * @author Thomas Risberg * @since 09.12.2003 * @see java.io.File * @see org.springframework.core.io.ResourceEditor * @see org.springframework.core.io.ResourceLoader * @see URLEditor * @see InputStreamEditor */ public class FileEditor extends PropertyEditorSupport { private final ResourceEditor resourceEditor; /** * Create a new FileEditor, using a default ResourceEditor underneath. */ public FileEditor() { this.resourceEditor = new ResourceEditor(); } /** * Create a new FileEditor, using the given ResourceEditor underneath. * @param resourceEditor the ResourceEditor to use */ public FileEditor(ResourceEditor resourceEditor) { Assert.notNull(resourceEditor, "ResourceEditor must not be null"); this.resourceEditor = resourceEditor; } @Override public void setAsText(String text) throws IllegalArgumentException { if (!StringUtils.hasText(text)) { setValue(null); return; } // Check whether we got an absolute file path without "file:" prefix. // For backwards compatibility, we'll consider those as straight file path. File file = null; if (!ResourceUtils.isUrl(text)) { file = new File(text); if (file.isAbsolute()) { setValue(file); return; } } // Proceed with standard resource location parsing. this.resourceEditor.setAsText(text); Resource resource = (Resource) this.resourceEditor.getValue(); // If it's a URL or a path pointing to an existing resource, use it as-is. if (file == null || resource.exists()) { try { setValue(resource.getFile()); } catch (IOException ex) { throw new IllegalArgumentException( "Could not retrieve file for " + resource + ": " + ex.getMessage()); } } else { // Set a relative File reference and hope for the best. setValue(file); } } @Override public String getAsText() { File value = (File) getValue(); return (value != null ? value.getPath() : ""); } }