Consistently throw FileNotFoundException even for NIO access

Issue: SPR-16334

Author: jhoeller

spring-core/src/main/java/org/springframework/core/io/AbstractFileResolvingResource.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -26,6 +26,7 @@
 import java.net.URLConnection;
 import java.nio.channels.FileChannel;
 import java.nio.channels.ReadableByteChannel;
+import java.nio.file.NoSuchFileException;
 import java.nio.file.StandardOpenOption;
 
 import org.springframework.util.ResourceUtils;
@@ -42,6 +43,68 @@
  */
 public abstract class AbstractFileResolvingResource extends AbstractResource {
 
+	@Override
+	public boolean exists() {
+		try {
+			URL url = getURL();
+			if (ResourceUtils.isFileURL(url)) {
+				// Proceed with file system resolution
+				return getFile().exists();
+			}
+			else {
+				// Try a URL connection content-length header
+				URLConnection con = url.openConnection();
+				customizeConnection(con);
+				HttpURLConnection httpCon =
+						(con instanceof HttpURLConnection ? (HttpURLConnection) con : null);
+				if (httpCon != null) {
+					int code = httpCon.getResponseCode();
+					if (code == HttpURLConnection.HTTP_OK) {
+						return true;
+					}
+					else if (code == HttpURLConnection.HTTP_NOT_FOUND) {
+						return false;
+					}
+				}
+				if (con.getContentLength() >= 0) {
+					return true;
+				}
+				if (httpCon != null) {
+					// no HTTP OK status, and no content-length header: give up
+					httpCon.disconnect();
+					return false;
+				}
+				else {
+					// Fall back to stream existence: can we open the stream?
+					InputStream is = getInputStream();
+					is.close();
+					return true;
+				}
+			}
+		}
+		catch (IOException ex) {
+			return false;
+		}
+	}
+
+	@Override
+	public boolean isReadable() {
+		try {
+			URL url = getURL();
+			if (ResourceUtils.isFileURL(url)) {
+				// Proceed with file system resolution
+				File file = getFile();
+				return (file.canRead() && !file.isDirectory());
+			}
+			else {
+				return true;
+			}
+		}
+		catch (IOException ex) {
+			return false;
+		}
+	}
+
 	@Override
 	public boolean isFile() {
 		try {
@@ -123,81 +186,20 @@ protected File getFile(URI uri) throws IOException {
 	 * This implementation returns a FileChannel for the given URI-identified
 	 * resource, provided that it refers to a file in the file system.
 	 * @since 5.0
-	 * @see #getFile(URI)
+	 * @see #getFile()
 	 */
 	@Override
 	public ReadableByteChannel readableChannel() throws IOException {
-		if (isFile()) {
+		try {
+			// Try file system channel
 			return FileChannel.open(getFile().toPath(), StandardOpenOption.READ);
 		}
-		else {
+		catch (FileNotFoundException | NoSuchFileException ex) {
+			// Fall back to InputStream adaptation in superclass
 			return super.readableChannel();
 		}
 	}
 
-
-	@Override
-	public boolean exists() {
-		try {
-			URL url = getURL();
-			if (ResourceUtils.isFileURL(url)) {
-				// Proceed with file system resolution
-				return getFile().exists();
-			}
-			else {
-				// Try a URL connection content-length header
-				URLConnection con = url.openConnection();
-				customizeConnection(con);
-				HttpURLConnection httpCon =
-						(con instanceof HttpURLConnection ? (HttpURLConnection) con : null);
-				if (httpCon != null) {
-					int code = httpCon.getResponseCode();
-					if (code == HttpURLConnection.HTTP_OK) {
-						return true;
-					}
-					else if (code == HttpURLConnection.HTTP_NOT_FOUND) {
-						return false;
-					}
-				}
-				if (con.getContentLength() >= 0) {
-					return true;
-				}
-				if (httpCon != null) {
-					// no HTTP OK status, and no content-length header: give up
-					httpCon.disconnect();
-					return false;
-				}
-				else {
-					// Fall back to stream existence: can we open the stream?
-					InputStream is = getInputStream();
-					is.close();
-					return true;
-				}
-			}
-		}
-		catch (IOException ex) {
-			return false;
-		}
-	}
-
-	@Override
-	public boolean isReadable() {
-		try {
-			URL url = getURL();
-			if (ResourceUtils.isFileURL(url)) {
-				// Proceed with file system resolution
-				File file = getFile();
-				return (file.canRead() && !file.isDirectory());
-			}
-			else {
-				return true;
-			}
-		}
-		catch (IOException ex) {
-			return false;
-		}
-	}
-
 	@Override
 	public long contentLength() throws IOException {
 		URL url = getURL();
@@ -231,7 +233,6 @@ public long lastModified() throws IOException {
 		return con.getLastModified();
 	}
 
-
 	/**
 	 * Customize the given {@link URLConnection}, obtained in the course of an
 	 * {@link #exists()}, {@link #contentLength()} or {@link #lastModified()} call.

spring-core/src/main/java/org/springframework/core/io/FileSystemResource.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -17,6 +17,7 @@
 package org.springframework.core.io;
 
 import java.io.File;
+import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
@@ -26,6 +27,7 @@
 import java.nio.channels.ReadableByteChannel;
 import java.nio.channels.WritableByteChannel;
 import java.nio.file.Files;
+import java.nio.file.NoSuchFileException;
 import java.nio.file.StandardOpenOption;
 
 import org.springframework.util.Assert;
@@ -115,12 +117,17 @@ public boolean isReadable() {
 	}
 
 	/**
-	 * This implementation opens a FileInputStream for the underlying file.
+	 * This implementation opens a NIO file stream for the underlying file.
 	 * @see java.io.FileInputStream
 	 */
 	@Override
 	public InputStream getInputStream() throws IOException {
-		return Files.newInputStream(this.file.toPath());
+		try {
+			return Files.newInputStream(this.file.toPath());
+		}
+		catch (NoSuchFileException ex) {
+			throw new FileNotFoundException(ex.getMessage());
+		}
 	}
 
 	/**
@@ -183,7 +190,12 @@ public File getFile() {
 	 */
 	@Override
 	public ReadableByteChannel readableChannel() throws IOException {
-		return FileChannel.open(this.file.toPath(), StandardOpenOption.READ);
+		try {
+			return FileChannel.open(this.file.toPath(), StandardOpenOption.READ);
+		}
+		catch (NoSuchFileException ex) {
+			throw new FileNotFoundException(ex.getMessage());
+		}
 	}
 
 	/**

spring-core/src/main/java/org/springframework/core/io/FileUrlResource.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -26,11 +26,13 @@
 import java.nio.file.Files;
 import java.nio.file.StandardOpenOption;
 
+import org.springframework.lang.Nullable;
 import org.springframework.util.ResourceUtils;
 
 /**
  * Subclass of {@link UrlResource} which assumes file resolution, to the degree
- * of implementing the {@link WritableResource} interface for it.
+ * of implementing the {@link WritableResource} interface for it. This resource
+ * variant also caches resolved {@link File} handles from {@link #getFile()}.
  *
  * <p>This is the class resolved by {@link DefaultResourceLoader} for a "file:..."
  * URL location, allowing a downcast to {@link WritableResource} for it.
@@ -44,6 +46,10 @@
  */
 public class FileUrlResource extends UrlResource implements WritableResource {
 
+	@Nullable
+	private volatile File file;
+
+
 	/**
 	 * Create a new {@code FileUrlResource} based on the given URL object.
 	 * <p>Note that this does not enforce "file" as URL protocol. If a protocol
@@ -71,11 +77,14 @@ public FileUrlResource(String location) throws MalformedURLException {
 
 
 	@Override
-	public Resource createRelative(String relativePath) throws MalformedURLException {
-		if (relativePath.startsWith("/")) {
-			relativePath = relativePath.substring(1);
+	public File getFile() throws IOException {
+		File file = this.file;
+		if (file != null) {
+			return file;
 		}
-		return new FileUrlResource(new URL(getURL(), relativePath));
+		file = super.getFile();
+		this.file = file;
+		return file;
 	}
 
 	@Override
@@ -106,4 +115,12 @@ public WritableByteChannel writableChannel() throws IOException {
 		return FileChannel.open(getFile().toPath(), StandardOpenOption.WRITE);
 	}
 
+	@Override
+	public Resource createRelative(String relativePath) throws MalformedURLException {
+		if (relativePath.startsWith("/")) {
+			relativePath = relativePath.substring(1);
+		}
+		return new FileUrlResource(new URL(getURL(), relativePath));
+	}
+
 }

spring-core/src/main/java/org/springframework/core/io/PathResource.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -26,6 +26,7 @@
 import java.nio.channels.ReadableByteChannel;
 import java.nio.channels.WritableByteChannel;
 import java.nio.file.Files;
+import java.nio.file.NoSuchFileException;
 import java.nio.file.OpenOption;
 import java.nio.file.Path;
 import java.nio.file.Paths;
@@ -202,7 +203,12 @@ public File getFile() throws IOException {
 	 */
 	@Override
 	public ReadableByteChannel readableChannel() throws IOException {
-		return Files.newByteChannel(this.path, StandardOpenOption.READ);
+		try {
+			return Files.newByteChannel(this.path, StandardOpenOption.READ);
+		}
+		catch (NoSuchFileException ex) {
+			throw new FileNotFoundException(ex.getMessage());
+		}
 	}
 
 	/**
@@ -215,7 +221,7 @@ public WritableByteChannel writableChannel() throws IOException {
 	}
 
 	/**
-	 * This implementation returns the underlying File's length.
+	 * This implementation returns the underlying file's length.
 	 */
 	@Override
 	public long contentLength() throws IOException {