现象
使用HttpClient工具上传文件时，如果文件名是中文，文件名会乱码
文件名乱码的代码：
private HttpEntity buildEntity(Long scenarioId, List<String> groupIds, String extension,File fileToUpload) { MultipartEntityBuilder builder = MultipartEntityBuilder.create(); builder.addTextBody("scenarioId", scenarioId.toString()); for (String groupId : groupIds) { builder.addTextBody("groupIds", groupId); } builder.addTextBody("extension", extension); builder.addPart("fileToUpload", new FileBody(fileToUpload)); builder.addTextBody("type", AssetFileTypeEnum.CSV.getName()); builder.addTextBody("isSplit", "false"); builder.addTextBody("isRefresh", "false"); return builder.build();
乱码原因：
HttpClient上传文件时，会调用doWriteTo方法，写一个输出流，但是在调用formatMultipartHeader方法时，底层主要有3种不同的实现，3种方式的采用的字符集不一样
HttpClient中的doWriteTo方法：
void doWriteTo( final OutputStream out, final boolean writeContent) throws IOException { final ByteArrayBuffer boundaryEncoded = encode(this.charset, this.boundary); for (final FormBodyPart part: getBodyParts()) { writeBytes(TWO_DASHES, out); writeBytes(boundaryEncoded, out); writeBytes(CR_LF, out); //此处代码主要有3种不同的实现,不同的mode,实现方式不一样，采用的字符集也不同 formatMultipartHeader(part, out); writeBytes(CR_LF, out); if (writeContent) { part.getBody().writeTo(out); } writeBytes(CR_LF, out); } writeBytes(TWO_DASHES, out); writeBytes(boundaryEncoded, out); writeBytes(TWO_DASHES, out); writeBytes(CR_LF, out); }
其中的formatMultipartHeader方法，不同的模式有不同的实现方式
MultipartEntityBuilder
MultipartFormEntity buildEntity() { String boundaryCopy = boundary; if (boundaryCopy == null && contentType != null) { boundaryCopy = contentType.getParameter("boundary"); } if (boundaryCopy == null) { boundaryCopy = generateBoundary(); } Charset charsetCopy = charset; if (charsetCopy == null && contentType != null) { charsetCopy = contentType.getCharset(); } final List<NameValuePair> paramsList = new ArrayList<NameValuePair>(2); paramsList.add(new BasicNameValuePair("boundary", boundaryCopy)); if (charsetCopy != null) { paramsList.add(new BasicNameValuePair("charset", charsetCopy.name())); } final NameValuePair[] params = paramsList.toArray(new NameValuePair[paramsList.size()]); final ContentType contentTypeCopy = contentType != null ? contentType.withParameters(params) : ContentType.create("multipart/" + DEFAULT_SUBTYPE, params); final List<FormBodyPart> bodyPartsCopy = bodyParts != null ? new ArrayList<FormBodyPart>(bodyParts) : Collections.<FormBodyPart>emptyList(); //此处将mode赋值给modeCopy final HttpMultipartMode modeCopy = mode != null ? mode : HttpMultipartMode.STRICT; final AbstractMultipartForm form; //此处根据modeCopy的值不同，构造3种form，每种的字符集都不一样，也是产生乱码的根源 switch (modeCopy) { case BROWSER_COMPATIBLE: form = new HttpBrowserCompatibleMultipart(charsetCopy, boundaryCopy, bodyPartsCopy); break; case RFC6532: form = new HttpRFC6532Multipart(charsetCopy, boundaryCopy, bodyPartsCopy); break; default: form = new HttpStrictMultipart(charsetCopy, boundaryCopy, bodyPartsCopy); } return new MultipartFormEntity(form, contentTypeCopy, form.getTotalLength()); } public HttpEntity build() { return buildEntity(); }
BROWSER_COMPATIBLE模式中的formatMultipartHeader方法
class HttpBrowserCompatibleMultipart extends AbstractMultipartForm { private final List<FormBodyPart> parts; public HttpBrowserCompatibleMultipart( final Charset charset, final String boundary, final List<FormBodyPart> parts) { super(charset, boundary); this.parts = parts; } @Override public List<FormBodyPart> getBodyParts() { return this.parts; } /** * Write the multipart header fields; depends on the style. */ @Override protected void formatMultipartHeader( final FormBodyPart part, final OutputStream out) throws IOException { // For browser-compatible, only write Content-Disposition // Use content charset final Header header = part.getHeader(); final MinimalField cd = header.getField(MIME.CONTENT_DISPOSITION); //可以看到此处的字符集采用的是设置的字符集 writeField(cd, this.charset, out); final String filename = part.getBody().getFilename(); if (filename != null) { final MinimalField ct = header.getField(MIME.CONTENT_TYPE); //可以看到此处的字符集采用的也是设置的字符集 writeField(ct, this.charset, out); } }}
RFC6532模式中的formatMultipartHeader方法
class HttpRFC6532Multipart extends AbstractMultipartForm { private final List<FormBodyPart> parts; public HttpRFC6532Multipart( final Charset charset, final String boundary, final List<FormBodyPart> parts) { super(charset, boundary); this.parts = parts; } @Override public List<FormBodyPart> getBodyParts() { return this.parts; } @Override protected void formatMultipartHeader( final FormBodyPart part, final OutputStream out) throws IOException { // For RFC6532, we output all fields with UTF-8 encoding. final Header header = part.getHeader(); for (final MinimalField field: header) { //可以看到此处的字符集默认采用UTF8 writeField(field, MIME.UTF8_CHARSET, out); } }}
默认模式中的formatMultipartHeader方法
class HttpStrictMultipart extends AbstractMultipartForm { private final List<FormBodyPart> parts; public HttpStrictMultipart( final Charset charset, final String boundary, final List<FormBodyPart> parts) { super(charset, boundary); this.parts = parts; } @Override public List<FormBodyPart> getBodyParts() { return this.parts; } @Override protected void formatMultipartHeader( final FormBodyPart part, final OutputStream out) throws IOException { // For strict, we output all fields with MIME-standard encoding. //从上面注释中可以看到，此处的字符集采用的是默认字符集即ASCII（下面MIME类中可以看到） final Header header = part.getHeader(); for (final MinimalField field: header) { writeField(field, out); } }}
MIME类
public final class MIME { public static final String CONTENT_TYPE = "Content-Type"; public static final String CONTENT_TRANSFER_ENC = "Content-Transfer-Encoding"; public static final String CONTENT_DISPOSITION = "Content-Disposition"; public static final String ENC_8BIT = "8bit"; public static final String ENC_BINARY = "binary"; /** The default character set to be used, i.e. "US-ASCII" */ public static final Charset DEFAULT_CHARSET = Consts.ASCII; /** UTF-8 is used for RFC6532 */ public static final Charset UTF8_CHARSET = Consts.UTF_8;}
解决方法
知道乱码产生的根源，乱码问题也就好解决了，解决方式有两种
设置mode为：BROWSER_COMPATIBLE，并设置字符集为UTF8
private HttpEntity buildEntity(Long scenarioId, List<String> groupIds, String extension, File fileToUpload) { MultipartEntityBuilder builder = MultipartEntityBuilder.create(); //设置模式为BROWSER_COMPATIBLE，并设置字符集为UTF8 builder.setMode(HttpMultipartMode.BROWSER_COMPATIBLE); builder.setCharset(Charset.forName("UTF-8")); builder.addTextBody("scenarioId", scenarioId.toString()); for (String groupId : groupIds) { builder.addTextBody("groupIds", groupId); } builder.addTextBody("extension", extension); builder.addPart("fileToUpload", new FileBody(fileToUpload)); builder.addTextBody("type", AssetFileTypeEnum.CSV.getName()); builder.addTextBody("isSplit", "false"); builder.addTextBody("isRefresh", "false"); return builder.build(); }
设置模式为：RFC6532
private HttpEntity buildEntity(Long scenarioId, List<String> groupIds, String extension, File fileToUpload) { MultipartEntityBuilder builder = MultipartEntityBuilder.create(); //设置模式为RFC6532 builder.setMode(HttpMultipartMode.RFC6532); builder.addTextBody("scenarioId", scenarioId.toString()); for (String groupId : groupIds) { builder.addTextBody("groupIds", groupId); } builder.addTextBody("extension", extension); builder.addPart("fileToUpload", new FileBody(fileToUpload)); builder.addTextBody("type", AssetFileTypeEnum.CSV.getName()); builder.addTextBody("isSplit", "false"); builder.addTextBody("isRefresh", "false"); return builder.build(); }
以上为个人经验，希望能给大家一个参考，也希望大家多多支持。
所有的失败，与失去自己的失败比起来，更是微不足道
