我得到的内容处置标头值如下。
附件;文件名*=UTF-8''专辑.jpeg
如何从中提取文件名(专辑.jpeg(。在查看值时，它具有编码格式值。
使用 Spring 的 ContentDisposition(从 5.0 版开始(来解析它。如果您负担不起将 Spring 作为依赖项添加到项目中的费用，则可以使用此实现(原始ContentDisposition剥离(。
import java.io.ByteArrayOutputStream;
import java.io.UnsupportedEncodingException;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.List;
import static java.nio.charset.StandardCharsets.ISO_8859_1;
import static java.nio.charset.StandardCharsets.UTF_8;
public class Main {
public static void main(String[] args) {
String fileName = ContentDispositionFileNameParser.parse("attachment; filename*=UTF-8''%D1%80%D1%83%D1%81%D1%81%D0%BA%D0%BE%D0%B5%20%D1%81%D0%BB%D0%BE%D0%B2%D0%BE.txt");
System.out.println(fileName);
}
}
/*
* Copyright 2002-2020 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.
*/
/**
* Parses "filename" parameter of the Content-Disposition HTTP header as defined in RFC 6266.
*
* @author Sebastien Deleuze
* @author Juergen Hoeller
* @author Rossen Stoyanchev
*/
final class ContentDispositionFileNameParser {
private static final String INVALID_HEADER_FIELD_PARAMETER_FORMAT = "Invalid header field parameter format (as defined in RFC 5987)";
/**
* Parse a {@literal Content-Disposition} header value as defined in RFC 2183.
*
* @param contentDisposition the {@literal Content-Disposition} header value
* @return Return the value of the {@literal filename} parameter (or the value of the
* {@literal filename*} one decoded as defined in the RFC 5987), or {@code null} if not defined.
*/
public static String parse(String contentDisposition) {
List<String> parts = tokenize(contentDisposition);
String filename = null;
Charset charset;
for (int i = 1; i < parts.size(); i++) {
String part = parts.get(i);
int eqIndex = part.indexOf('=');
if (eqIndex != -1) {
String attribute = part.substring(0, eqIndex);
String value = (part.startsWith(""", eqIndex + 1) && part.endsWith(""") ?
part.substring(eqIndex + 2, part.length() - 1) :
part.substring(eqIndex + 1));
if (attribute.equals("filename*")) {
int idx1 = value.indexOf(''');
int idx2 = value.indexOf(''', idx1 + 1);
if (idx1 != -1 && idx2 != -1) {
charset = Charset.forName(value.substring(0, idx1).trim());
if (!(UTF_8.equals(charset) || ISO_8859_1.equals(charset))) {
throw new IllegalArgumentException("Charset should be UTF-8 or ISO-8859-1");
}
filename = decodeFilename(value.substring(idx2 + 1), charset);
} else {
// US ASCII
filename = decodeFilename(value, StandardCharsets.US_ASCII);
}
} else if (attribute.equals("filename") && (filename == null)) {
filename = value;
}
} else {
throw new IllegalArgumentException("Invalid content disposition format");
}
}
return filename;
}
private static List<String> tokenize(String headerValue) {
int index = headerValue.indexOf(';');
String type = (index >= 0 ? headerValue.substring(0, index) : headerValue).trim();
if (type.isEmpty()) {
throw new IllegalArgumentException("Content-Disposition header must not be empty");
}
List<String> parts = new ArrayList<>();
parts.add(type);
if (index >= 0) {
do {
int nextIndex = index + 1;
boolean quoted = false;
boolean escaped = false;
while (nextIndex < headerValue.length()) {
char ch = headerValue.charAt(nextIndex);
if (ch == ';') {
if (!quoted) {
break;
}
} else if (!escaped && ch == '"') {
quoted = !quoted;
}
escaped = (!escaped && ch == '\');
nextIndex++;
}
String part = headerValue.substring(index + 1, nextIndex).trim();
if (!part.isEmpty()) {
parts.add(part);
}
index = nextIndex;
}
while (index < headerValue.length());
}
return parts;
}
/**
* Decode the given header field param as described in RFC 5987.
* <p>Only the US-ASCII, UTF-8 and ISO-8859-1 charsets are supported.
*
* @param filename the filename
* @param charset the charset for the filename
* @return the encoded header field param
*/
private static String decodeFilename(String filename, Charset charset) {
if (filename == null) {
throw new IllegalArgumentException("'input' String` should not be null");
}
if (charset == null) {
throw new IllegalArgumentException("'charset' should not be null");
}
byte[] value = filename.getBytes(charset);
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
int index = 0;
while (index < value.length) {
byte b = value[index];
if (isRFC5987AttrChar(b)) {
byteArrayOutputStream.write((char) b);
index++;
} else if (b == '%' && index < value.length - 2) {
char[] array = new char[] {(char) value[index + 1], (char) value[index + 2]};
try {
byteArrayOutputStream.write(Integer.parseInt(String.valueOf(array), 16));
} catch (NumberFormatException ex) {
throw new IllegalArgumentException(INVALID_HEADER_FIELD_PARAMETER_FORMAT, ex);
}
index += 3;
} else {
throw new IllegalArgumentException(INVALID_HEADER_FIELD_PARAMETER_FORMAT);
}
}
try {
return byteArrayOutputStream.toString(charset.name());
} catch (UnsupportedEncodingException e) {
throw new RuntimeException("Failed to copy contents of ByteArrayOutputStream into a String", e);
}
}
private static boolean isRFC5987AttrChar(byte c) {
return (c >= '0' && c <= '9') || (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') ||
c == '!' || c == '#' || c == '$' || c == '&' || c == '+' || c == '-' ||
c == '.' || c == '^' || c == '_' || c == '`' || c == '|' || c == '~';
}
}
filename*参数在 RFC 6266 中定义
要使用 java 解码文件名：
String contentd = "attachment;filename*=UTF-8''album.jpeg";
String filename = java.net.URLDecoder.decode(contentd.substring(contentd.indexOf("''")+2), "UTF-8");