001/* 002 * Copyright 2002-2017 the original author or authors. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * https://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package org.springframework.core.io; 018 019import java.beans.PropertyEditorSupport; 020import java.io.IOException; 021 022import org.springframework.core.env.PropertyResolver; 023import org.springframework.core.env.StandardEnvironment; 024import org.springframework.lang.Nullable; 025import org.springframework.util.Assert; 026import org.springframework.util.StringUtils; 027 028/** 029 * {@link java.beans.PropertyEditor Editor} for {@link Resource} 030 * descriptors, to automatically convert {@code String} locations 031 * e.g. {@code file:C:/myfile.txt} or {@code classpath:myfile.txt} to 032 * {@code Resource} properties instead of using a {@code String} location property. 033 * 034 * <p>The path may contain {@code ${...}} placeholders, to be 035 * resolved as {@link org.springframework.core.env.Environment} properties: 036 * e.g. {@code ${user.dir}}. Unresolvable placeholders are ignored by default. 037 * 038 * <p>Delegates to a {@link ResourceLoader} to do the heavy lifting, 039 * by default using a {@link DefaultResourceLoader}. 040 * 041 * @author Juergen Hoeller 042 * @author Dave Syer 043 * @author Chris Beams 044 * @since 28.12.2003 045 * @see Resource 046 * @see ResourceLoader 047 * @see DefaultResourceLoader 048 * @see PropertyResolver#resolvePlaceholders 049 */ 050public class ResourceEditor extends PropertyEditorSupport { 051 052 private final ResourceLoader resourceLoader; 053 054 @Nullable 055 private PropertyResolver propertyResolver; 056 057 private final boolean ignoreUnresolvablePlaceholders; 058 059 060 /** 061 * Create a new instance of the {@link ResourceEditor} class 062 * using a {@link DefaultResourceLoader} and {@link StandardEnvironment}. 063 */ 064 public ResourceEditor() { 065 this(new DefaultResourceLoader(), null); 066 } 067 068 /** 069 * Create a new instance of the {@link ResourceEditor} class 070 * using the given {@link ResourceLoader} and {@link PropertyResolver}. 071 * @param resourceLoader the {@code ResourceLoader} to use 072 * @param propertyResolver the {@code PropertyResolver} to use 073 */ 074 public ResourceEditor(ResourceLoader resourceLoader, @Nullable PropertyResolver propertyResolver) { 075 this(resourceLoader, propertyResolver, true); 076 } 077 078 /** 079 * Create a new instance of the {@link ResourceEditor} class 080 * using the given {@link ResourceLoader}. 081 * @param resourceLoader the {@code ResourceLoader} to use 082 * @param propertyResolver the {@code PropertyResolver} to use 083 * @param ignoreUnresolvablePlaceholders whether to ignore unresolvable placeholders 084 * if no corresponding property could be found in the given {@code propertyResolver} 085 */ 086 public ResourceEditor(ResourceLoader resourceLoader, @Nullable PropertyResolver propertyResolver, 087 boolean ignoreUnresolvablePlaceholders) { 088 089 Assert.notNull(resourceLoader, "ResourceLoader must not be null"); 090 this.resourceLoader = resourceLoader; 091 this.propertyResolver = propertyResolver; 092 this.ignoreUnresolvablePlaceholders = ignoreUnresolvablePlaceholders; 093 } 094 095 096 @Override 097 public void setAsText(String text) { 098 if (StringUtils.hasText(text)) { 099 String locationToUse = resolvePath(text).trim(); 100 setValue(this.resourceLoader.getResource(locationToUse)); 101 } 102 else { 103 setValue(null); 104 } 105 } 106 107 /** 108 * Resolve the given path, replacing placeholders with corresponding 109 * property values from the {@code environment} if necessary. 110 * @param path the original file path 111 * @return the resolved file path 112 * @see PropertyResolver#resolvePlaceholders 113 * @see PropertyResolver#resolveRequiredPlaceholders 114 */ 115 protected String resolvePath(String path) { 116 if (this.propertyResolver == null) { 117 this.propertyResolver = new StandardEnvironment(); 118 } 119 return (this.ignoreUnresolvablePlaceholders ? this.propertyResolver.resolvePlaceholders(path) : 120 this.propertyResolver.resolveRequiredPlaceholders(path)); 121 } 122 123 124 @Override 125 @Nullable 126 public String getAsText() { 127 Resource value = (Resource) getValue(); 128 try { 129 // Try to determine URL for resource. 130 return (value != null ? value.getURL().toExternalForm() : ""); 131 } 132 catch (IOException ex) { 133 // Couldn't determine resource URL - return null to indicate 134 // that there is no appropriate text representation. 135 return null; 136 } 137 } 138 139}