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：
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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();
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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：
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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);
}
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其中的formatMultipartHeader方法，不同的模式有不同的实现方式
MultipartEntityBuilder
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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();
}
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BROWSER_COMPATIBLE模式中的formatMultipartHeader方法
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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);
}
}
}
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RFC6532模式中的formatMultipartHeader方法
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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);
}
}
}
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默认模式中的formatMultipartHeader方法
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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);
}
}
}
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MIME类
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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;
}
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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
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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();
}
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设置模式为：RFC6532
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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();
}
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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服务器之家。
原文链接：https://blog.csdn.net/youshounianhua123/article/details/81100778