FileCopyUtils & Base64Utils
springBabi太贴心了，文件拷贝的工具类也给我们提供了
FileCopyUtils
/*
* 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.
* 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.util;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.Reader;
import java.io.StringWriter;
import java.io.Writer;
import java.nio.file.Files;
import org.springframework.lang.Nullable;
/**
* Simple utility methods for file and stream copying. All copy methods use a block size
* of 4096 bytes, and close all affected streams when done. A variation of the copy
* methods from this class that leave streams open can be found in {@link StreamUtils}.
*
* Mainly for use within the framework, but also useful for application code.
*
* @author Juergen Hoeller
* @since 06.10.2003
* @see StreamUtils
* @see FileSystemUtils
*/
public abstract class FileCopyUtils {
/**
* The default buffer size used when copying bytes.
*/
public static final int BUFFER_SIZE = StreamUtils.BUFFER_SIZE;
//---------------------------------------------------------------------
// Copy methods for java.io.File
//---------------------------------------------------------------------
/**
* Copy the contents of the given input File to the given output File.
* @param in the file to copy from
* @param out the file to copy to
* @return the number of bytes copied
* @throws IOException in case of I/O errors
*/
public static int copy(File in, File out) throws IOException {
Assert.notNull(in, "No input File specified");
Assert.notNull(out, "No output File specified");
return copy(Files.newInputStream(in.toPath()), Files.newOutputStream(out.toPath()));
}
/**
* Copy the contents of the given byte array to the given output File.
* @param in the byte array to copy from
* @param out the file to copy to
* @throws IOException in case of I/O errors
*/
public static void copy(byte[] in, File out) throws IOException {
Assert.notNull(in, "No input byte array specified");
Assert.notNull(out, "No output File specified");
copy(new ByteArrayInputStream(in), Files.newOutputStream(out.toPath()));
}
/**
* Copy the contents of the given input File into a new byte array.
* @param in the file to copy from
* @return the new byte array that has been copied to
* @throws IOException in case of I/O errors
*/
public static byte[] copyToByteArray(File in) throws IOException {
Assert.notNull(in, "No input File specified");
return copyToByteArray(Files.newInputStream(in.toPath()));
}
//---------------------------------------------------------------------
// Copy methods for java.io.InputStream / java.io.OutputStream
//---------------------------------------------------------------------
/**
* Copy the contents of the given InputStream to the given OutputStream.
* Closes both streams when done.
* @param in the stream to copy from
* @param out the stream to copy to
* @return the number of bytes copied
* @throws IOException in case of I/O errors
*/
public static int copy(InputStream in, OutputStream out) throws IOException {
Assert.notNull(in, "No InputStream specified");
Assert.notNull(out, "No OutputStream specified");
try {
return StreamUtils.copy(in, out);
}
finally {
try {
in.close();
}
catch (IOException ex) {
}
try {
out.close();
}
catch (IOException ex) {
}
}
}
/**
* Copy the contents of the given byte array to the given OutputStream.
* Closes the stream when done.
* @param in the byte array to copy from
* @param out the OutputStream to copy to
* @throws IOException in case of I/O errors
*/
public static void copy(byte[] in, OutputStream out) throws IOException {
Assert.notNull(in, "No input byte array specified");
Assert.notNull(out, "No OutputStream specified");
try {
out.write(in);
}
finally {
try {
out.close();
}
catch (IOException ex) {
}
}
}
/**
* Copy the contents of the given InputStream into a new byte array.
* Closes the stream when done.
* @param in the stream to copy from (may be {@code null} or empty)
* @return the new byte array that has been copied to (possibly empty)
* @throws IOException in case of I/O errors
*/
public static byte[] copyToByteArray(@Nullable InputStream in) throws IOException {
if (in == null) {
return new byte[0];
}
ByteArrayOutputStream out = new ByteArrayOutputStream(BUFFER_SIZE);
copy(in, out);
return out.toByteArray();
}
//---------------------------------------------------------------------
// Copy methods for java.io.Reader / java.io.Writer
//---------------------------------------------------------------------
/**
* Copy the contents of the given Reader to the given Writer.
* Closes both when done.
* @param in the Reader to copy from
* @param out the Writer to copy to
* @return the number of characters copied
* @throws IOException in case of I/O errors
*/
public static int copy(Reader in, Writer out) throws IOException {
Assert.notNull(in, "No Reader specified");
Assert.notNull(out, "No Writer specified");
try {
int byteCount = 0;
char[] buffer = new char[BUFFER_SIZE];
int bytesRead = -1;
while ((bytesRead = in.read(buffer)) != -1) {
out.write(buffer, 0, bytesRead);
byteCount += bytesRead;
}
out.flush();
return byteCount;
}
finally {
try {
in.close();
}
catch (IOException ex) {
}
try {
out.close();
}
catch (IOException ex) {
}
}
}
/**
* Copy the contents of the given String to the given output Writer.
* Closes the writer when done.
* @param in the String to copy from
* @param out the Writer to copy to
* @throws IOException in case of I/O errors
*/
public static void copy(String in, Writer out) throws IOException {
Assert.notNull(in, "No input String specified");
Assert.notNull(out, "No Writer specified");
try {
out.write(in);
}
finally {
try {
out.close();
}
catch (IOException ex) {
}
}
}
/**
* Copy the contents of the given Reader into a String.
* Closes the reader when done.
* @param in the reader to copy from (may be {@code null} or empty)
* @return the String that has been copied to (possibly empty)
* @throws IOException in case of I/O errors
*/
public static String copyToString(@Nullable Reader in) throws IOException {
if (in == null) {
return "";
}
StringWriter out = new StringWriter();
copy(in, out);
return out.toString();
}
}
Base64Utils
/*
* Copyright 2002-2019 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.util;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.util.Base64;
/**
* A simple utility class for Base64 encoding and decoding.
*
* Adapts to Java 8's {@link java.util.Base64} in a convenience fashion.
*
* @author Juergen Hoeller
* @author Gary Russell
* @since 4.1
* @see java.util.Base64
*/
public abstract class Base64Utils {
private static final Charset DEFAULT_CHARSET = StandardCharsets.UTF_8;
/**
* Base64-encode the given byte array.
* @param src the original byte array
* @return the encoded byte array
*/
public static byte[] encode(byte[] src) {
if (src.length == 0) {
return src;
}
return Base64.getEncoder().encode(src);
}
/**
* Base64-decode the given byte array.
* @param src the encoded byte array
* @return the original byte array
*/
public static byte[] decode(byte[] src) {
if (src.length == 0) {
return src;
}
return Base64.getDecoder().decode(src);
}
/**
* Base64-encode the given byte array using the RFC 4648
* "URL and Filename Safe Alphabet".
* @param src the original byte array
* @return the encoded byte array
* @since 4.2.4
*/
public static byte[] encodeUrlSafe(byte[] src) {
if (src.length == 0) {
return src;
}
return Base64.getUrlEncoder().encode(src);
}
/**
* Base64-decode the given byte array using the RFC 4648
* "URL and Filename Safe Alphabet".
* @param src the encoded byte array
* @return the original byte array
* @since 4.2.4
*/
public static byte[] decodeUrlSafe(byte[] src) {
if (src.length == 0) {
return src;
}
return Base64.getUrlDecoder().decode(src);
}
/**
* Base64-encode the given byte array to a String.
* @param src the original byte array
* @return the encoded byte array as a UTF-8 String
*/
public static String encodeToString(byte[] src) {
if (src.length == 0) {
return "";
}
return new String(encode(src), DEFAULT_CHARSET);
}
/**
* Base64-decode the given byte array from an UTF-8 String.
* @param src the encoded UTF-8 String
* @return the original byte array
*/
public static byte[] decodeFromString(String src) {
if (src.isEmpty()) {
return new byte[0];
}
return decode(src.getBytes(DEFAULT_CHARSET));
}
/**
* Base64-encode the given byte array to a String using the RFC 4648
* "URL and Filename Safe Alphabet".
* @param src the original byte array
* @return the encoded byte array as a UTF-8 String
*/
public static String encodeToUrlSafeString(byte[] src) {
return new String(encodeUrlSafe(src), DEFAULT_CHARSET);
}
/**
* Base64-decode the given byte array from an UTF-8 String using the RFC 4648
* "URL and Filename Safe Alphabet".
* @param src the encoded UTF-8 String
* @return the original byte array
*/
public static byte[] decodeFromUrlSafeString(String src) {
return decodeUrlSafe(src.getBytes(DEFAULT_CHARSET));
}
}