com.alibaba.nacos.common.packagescan.resource.ClassPathResource Maven / Gradle / Ivy
/*
* Copyright 2002-2021 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 com.alibaba.nacos.common.packagescan.resource;
import com.alibaba.nacos.common.utils.AbstractObjectUtils;
import com.alibaba.nacos.common.utils.AbstractAssert;
import com.alibaba.nacos.common.utils.ClassUtils;
import com.alibaba.nacos.common.utils.StringUtils;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
/**
* Copy from https://github.com/spring-projects/spring-framework.git, with less modifications
* {@link Resource} implementation for class path resources. Uses either a
* given {@link ClassLoader} or a given {@link Class} for loading resources.
*
* Supports resolution as {@code java.io.File} if the class path
* resource resides in the file system, but not for resources in a JAR.
* Always supports resolution as URL.
*
* @author Juergen Hoeller
* @author Sam Brannen
* @see ClassLoader#getResourceAsStream(String)
* @see Class#getResourceAsStream(String)
* @since 28.12.2003
*/
public class ClassPathResource extends AbstractFileResolvingResource {
private final String path;
private ClassLoader classLoader;
private Class clazz;
/**
* Create a new {@code ClassPathResource} for {@code ClassLoader} usage.
* A leading slash will be removed, as the ClassLoader resource access
* methods will not accept it.
*
*
The thread context class loader will be used for
* loading the resource.
*
* @param path the absolute path within the class path
* @see ClassLoader#getResourceAsStream(String)
* @see ClassUtils#getDefaultClassLoader()
*/
public ClassPathResource(String path) {
this(path, (ClassLoader) null);
}
/**
* Create a new {@code ClassPathResource} for {@code ClassLoader} usage.
* A leading slash will be removed, as the ClassLoader resource access
* methods will not accept it.
*
* @param path the absolute path within the classpath
* @param classLoader the class loader to load the resource with,
* or {@code null} for the thread context class loader
* @see ClassLoader#getResourceAsStream(String)
*/
public ClassPathResource(String path, ClassLoader classLoader) {
AbstractAssert.notNull(path, "Path must not be null");
String pathToUse = StringUtils.cleanPath(path);
if (pathToUse.startsWith("/")) {
pathToUse = pathToUse.substring(1);
}
this.path = pathToUse;
this.classLoader = (classLoader != null ? classLoader : ClassUtils.getDefaultClassLoader());
}
/**
* Create a new {@code ClassPathResource} for {@code Class} usage.
* The path can be relative to the given class, or absolute within
* the classpath via a leading slash.
*
* @param path relative or absolute path within the class path
* @param clazz the class to load resources with
* @see Class#getResourceAsStream
*/
public ClassPathResource(String path, Class clazz) {
AbstractAssert.notNull(path, "Path must not be null");
this.path = StringUtils.cleanPath(path);
this.clazz = clazz;
}
/**
* Create a new {@code ClassPathResource} with optional {@code ClassLoader}
* and {@code Class}. Only for internal usage.
*
* @param path relative or absolute path within the classpath
* @param classLoader the class loader to load the resource with, if any
* @param clazz the class to load resources with, if any
* @deprecated as of 4.3.13, in favor of selective use of
* {@link #ClassPathResource(String, ClassLoader)} vs {@link #ClassPathResource(String, Class)}
*/
@Deprecated
protected ClassPathResource(String path, ClassLoader classLoader, Class clazz) {
this.path = StringUtils.cleanPath(path);
this.classLoader = classLoader;
this.clazz = clazz;
}
/**
* Return the path for this resource (as resource path within the class path).
*/
public final String getPath() {
return this.path;
}
/**
* Return the ClassLoader that this resource will be obtained from.
*/
public final ClassLoader getClassLoader() {
return (this.clazz != null ? this.clazz.getClassLoader() : this.classLoader);
}
/**
* This implementation checks for the resolution of a resource URL.
*
* @see ClassLoader#getResource(String)
* @see Class#getResource(String)
*/
@Override
public boolean exists() {
return (resolveUrl() != null);
}
/**
* This implementation checks for the resolution of a resource URL upfront,
* then proceeding with {@link AbstractFileResolvingResource}'s length check.
*
* @see ClassLoader#getResource(String)
* @see Class#getResource(String)
*/
@Override
public boolean isReadable() {
URL url = resolveUrl();
return (url != null && checkReadable(url));
}
/**
* Resolves a URL for the underlying class path resource.
*
* @return the resolved URL, or {@code null} if not resolvable
*/
protected URL resolveUrl() {
try {
if (this.clazz != null) {
return this.clazz.getResource(this.path);
} else if (this.classLoader != null) {
return this.classLoader.getResource(this.path);
} else {
return ClassLoader.getSystemResource(this.path);
}
} catch (IllegalArgumentException ex) {
// Should not happen according to the JDK's contract:
// see https://github.com/openjdk/jdk/pull/2662
return null;
}
}
/**
* This implementation opens an InputStream for the given class path resource.
*
* @see ClassLoader#getResourceAsStream(String)
* @see Class#getResourceAsStream(String)
*/
@Override
public InputStream getInputStream() throws IOException {
InputStream is;
if (this.clazz != null) {
is = this.clazz.getResourceAsStream(this.path);
} else if (this.classLoader != null) {
is = this.classLoader.getResourceAsStream(this.path);
} else {
is = ClassLoader.getSystemResourceAsStream(this.path);
}
if (is == null) {
throw new FileNotFoundException(getDescription() + " cannot be opened because it does not exist");
}
return is;
}
/**
* This implementation returns a URL for the underlying class path resource,
* if available.
*
* @see ClassLoader#getResource(String)
* @see Class#getResource(String)
*/
@Override
public URL getUrl() throws IOException {
URL url = resolveUrl();
if (url == null) {
throw new FileNotFoundException(getDescription() + " cannot be resolved to URL because it does not exist");
}
return url;
}
/**
* This implementation creates a ClassPathResource, applying the given path
* relative to the path of the underlying resource of this descriptor.
*
* @see StringUtils#applyRelativePath(String, String)
*/
@Override
public Resource createRelative(String relativePath) {
String pathToUse = StringUtils.applyRelativePath(this.path, relativePath);
return (this.clazz != null ? new ClassPathResource(pathToUse, this.clazz) :
new ClassPathResource(pathToUse, this.classLoader));
}
/**
* This implementation returns the name of the file that this class path
* resource refers to.
*
* @see StringUtils#getFilename(String)
*/
@Override
public String getFilename() {
return StringUtils.getFilename(this.path);
}
/**
* This implementation returns a description that includes the class path location.
*/
@Override
public String getDescription() {
StringBuilder builder = new StringBuilder("class path resource [");
String pathToUse = this.path;
if (this.clazz != null && !pathToUse.startsWith("/")) {
builder.append(ClassUtils.classPackageAsResourcePath(this.clazz));
builder.append('/');
}
if (pathToUse.startsWith("/")) {
pathToUse = pathToUse.substring(1);
}
builder.append(pathToUse);
builder.append(']');
return builder.toString();
}
/**
* This implementation compares the underlying class path locations.
*/
@Override
public boolean equals(Object other) {
if (this == other) {
return true;
}
if (!(other instanceof ClassPathResource)) {
return false;
}
ClassPathResource otherRes = (ClassPathResource) other;
return (this.path.equals(otherRes.path)
&& AbstractObjectUtils.nullSafeEquals(this.classLoader, otherRes.classLoader)
&& AbstractObjectUtils.nullSafeEquals(this.clazz, otherRes.clazz));
}
/**
* This implementation returns the hash code of the underlying
* class path location.
*/
@Override
public int hashCode() {
return this.path.hashCode();
}
}