如何更改字符串编码？
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【中文标题】如何更改字符串编码？【英文标题】：How do I change string encoding? 【发布时间】：2016-06-25 12:15:15 【问题描述】：我有问题。我有一个String
String str="Привет";
我尝试通过POST 请求发送到服务器。接收此字符串的网站具有 windows-1251 字符集（在服务器上，所有文件、数据、文本等都有 windows-1251）。它很好地显示了它的所有数据，除了从我的 Java 应用程序接收到的俄罗斯符号。我用谷歌搜索了这个问题，如何在我的 Java 应用程序中更改字符串编码，但仍然没有解决方案。
我试过这样做
String str=new String("Привет".getBytes("utf-8"),"cp1251");
但这并没有帮助。
所以问题是：如何将 Java utf-8 字符串转换为 cp1251，以便接受 cp1251 编码的 Web 服务器正确显示从我那里收到的所有数据。
这是我发送请求的方式：
protected Map<String, String> getFromUrl(String url, boolean post, Map<String,String> postParams, Map<String,String> files, boolean options, String fbt, String asFile)
dataStream=null;
bodyStream=null;
url=url.replaceAll("(?iu)^(http(s?)[://]*)+", "http$2://").replaceAll("(\\+|\\s+)", "%20");
if(url.matches("(?iu)^https://.*$"))return getFromUrlSSL(url,post,postParams,files,options,fbt,asFile);
else if(!url.matches("(?iu)^((http(s?))|ftp)://.*$"))url="http://"+url;
if(url.length()>2048)url=url.substring(0,2048);
System.out.println("/*Trying to connect to "+url+"*/");
Map<String, String> mp = new HashMap<String, String>();
String host = this.getHostName(url), content = "", UA = this.getUA(), cookie = this.getCookie(host, UA), referer = "http://"+host+"/";
try
mp.put("User-Agent",UA);
mp.put("cookies",cookie);
URL U = new URL(url);
HttpURLConnection conn = (HttpURLConnection)U.openConnection();
conn.setInstanceFollowRedirects(false);
conn.setRequestProperty("Host", host);
conn.setRequestProperty("User-Agent", UA);
conn.setRequestProperty("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8");
conn.setRequestProperty("Accept-Language", "ru-ru,ru;q=0.8,en-us;q=0.5,en;q=0.3");
conn.setRequestProperty("Accept-Encoding", "gzip,deflate");
conn.setRequestProperty("Accept-Charset", "utf-8;q=0.7,*;q=0.7");
conn.setRequestProperty("Keep-Alive", "115");
conn.setRequestProperty("Connection", "keep-alive");
if(arp!=null)for(Map.Entry<String, String> entry : arp.entrySet())conn.setRequestProperty(entry.getKey(),entry.getValue());
if(referer != null&&(arp==null||!arp.containsKey("Referer")))conn.setRequestProperty("Referer", referer);
if(cookie != null && !cookie.contentEquals(""))conn.setRequestProperty("Cookie", cookie);
if(post&&(postParams!=null&&postParams.size()>0||files!=null&&files.size()>0))
if(!options)conn.setRequestMethod("POST");
else conn.setRequestMethod("OPTIONS");
conn.setDoOutput(true);
OutputStream os;
BufferedWriter writer;
if(files!=null&&files.size()>0)
String boundary = Long.toHexString(System.currentTimeMillis());
conn.setRequestProperty("Content-Type","multipart/form-data; boundary="+boundary);
os=conn.getOutputStream();
writer=new BufferedWriter(new OutputStreamWriter(os, "UTF-8"));;
if(postParams!=null&&postParams.size()>0)
Iterator it=postParams.entrySet().iterator();
while(it.hasNext())
Map.Entry<String,String> pair=(Map.Entry<String, String>)it.next();
writer.append("--" + boundary).append("\r\n");
writer.append("Content-Disposition: form-data; name=\""+pair.getKey()+"\"").append("\r\n");
writer.append("\r\n");
writer.append(pair.getValue()).append("\r\n");
Iterator fIt=files.entrySet().iterator();
while(fIt.hasNext())try
Map.Entry<String, String> fPair=(Map.Entry<String, String>)fIt.next();
String filename=fPair.getValue();
System.out.println("/*"+filename+"*/");
if(!filename.matches("(?iu)^[\\s\\S]*?Content-Disposition. form-data[\\s\\S]*$"))
File file=null;
System.out.println("/*"+filename+"*/");
String fe=filename.matches("(?iu)^.*?(\\.[a-z0-9]1,5)$")?filename.replaceAll("(?iu)^.*?(\\.[a-z0-9]1,5)$","$1"):".jpg";
if(filename.matches("(?iu)^(http|ftp).*$"))
getFileFromUrl(filename,System.getProperty("user.dir")+"\\curFile"+fe);
file = new File(System.getProperty("user.dir")+"\\curFile"+fe);
else file = new File(filename);
try
BufferedImage bimg = ImageIO.read(file);
int width = bimg.getWidth();
int height = bimg.getHeight();
if(width<150||height<150)file=null;
else if(width/height>3||height/width>3)file=null;
else if(width>1024||height>1024)
float ii=width/height,w=ii>0?1024:height/width*1024,h=ii>0?width/height*1024:1024;
int type = bimg.getType() == 0? BufferedImage.TYPE_INT_ARGB : bimg.getType();
BufferedImage img = resizeImage(bimg,type,(int)w,(int)h);
ImageIO.write(img, "jpg", file);
if(filename.matches("(?iu)^(http|ftp).*$"))file = new File(System.getProperty("user.dir")+"\\curFile"+fe);
else new File(filename);
catch(Exception e)
Error.showError("Browser.getFromUrl() can't get data from url",e);
return new HashMap<String,String>()put("error","fileerror");;
if(file!=null)
writer.append("--" + boundary).append("\r\n");
writer.append("Content-Disposition: form-data; name=\""+fPair.getKey()+"\"; filename=\""+file.getName()+"\"").append("\r\n");
writer.append("Content-Type: application/octet-stream").append("\r\n");
writer.append("\r\n").flush();
InputStream input = new FileInputStream(file);
//System.out.println(conn.getOutputStream());
try
byte[] buffer = new byte[1024];
for(int length = 0;(length = input.read(buffer))>0;)os.write(buffer, 0, length);
os.flush();
finallytryinput.close();catch (IOException logOrIgnore)
writer.append("\r\n").flush();
catch(Exception e)
Error.showError("Browser.getFromUrl() can't get data from url",e);
return new HashMap<String,String>()put("error","fileerror");;
writer.append("--" + boundary + "--").append("\r\n");
else
String params="";
Iterator it=postParams.entrySet().iterator();
while(it.hasNext())
Map.Entry<String,String> pair=(Map.Entry<String, String>)it.next();
//System.out.println(pair.getKey()+"="+pair.getValue());
/*if(pair.getKey().trim().contentEquals("")&&arp.get("Content-Type")!=null&&arp.get("Content-Type").matches("(?iu)^[\\s\\S]*?application/json[\\s\\S]$"))params+=pair.getValue();
else */
params+=URLEncoder.encode(pair.getKey(),"UTF-8")+"="+URLEncoder.encode(pair.getValue(),"UTF-8")+"&";
params=params.replaceAll("&+$","");
if(fbt!=null)conn.setRequestProperty("Content-Type",fbt);
os=conn.getOutputStream();
writer=new BufferedWriter(new OutputStreamWriter(os, "UTF-8"));
if(fbt!=null)
writer.append("Content-Type: "+fbt).append("\r\n");
writer.append("Content-Length: "+params.length()).append("\r\n").append("\r\n");
if(fbt.matches("(?iu)^.*boundary=.*$"))
String boundary=fbt.replaceAll("(?iu)^[\\s\\S]*?boundary=([^;]+)[\\s\\S]*$","$1");
writer.append(boundary).append("\r\n");
it=postParams.entrySet().iterator();
//System.out.println(boundary);System.exit(1);
while(it.hasNext())
Map.Entry<String,String> pair=(Map.Entry<String, String>)it.next();
writer.append("Content-Disposition: form-data; name=\""+pair.getKey()+"\"").append("\r\n\r\n");
writer.append(pair.getValue()).append("\r\n");
writer.append(boundary).append("\r\n");
else writer.append(params.replaceAll("(^[=&\\s])|([\\s=&]$)",""));
else writer.write(params.replaceAll("(^[=&\\s])|([\\s=&]$)",""));
writer.flush();
writer.close();
os.close();
//System.out.println(conn.getOutputStream());
conn.setConnectTimeout(120000);
conn.setReadTimeout(120000);
else
conn.setConnectTimeout(7000);
conn.setReadTimeout(7000);
conn.connect();
//System.out.println(mp.get("cookies"));
mp = processResponseHeaders(conn.getHeaderFields());
//System.out.println(mp.get("cookies"));
if(mp.get("cookies")!=null && !mp.get("cookies").trim().contentEquals("") && !mp.get("cookies").contentEquals(cookie))this.setCookie(host, UA, cookie+"; "+mp.get("cookies"));
if((needRedirect!=null&&!needRedirect.contentEquals("")) && curRedirect<5)
if(!needRedirect.matches("(?i)^(.3,5?://)[\\s\\S]*$"))needRedirect = needRedirect.replaceAll("^([^\\.]*?://)?[^/\\?\\=\\&]*([/\\?\\=\\&])", url.replaceAll("^((http[s]?|ftp)://([^/\\?\\=\\&]*))[\\s\\S]*$","$1")+"$2");
return getFromUrl(needRedirect,false,null,null,false,null,asFile);
try
dataStream = conn.getErrorStream() != null ? conn.getErrorStream() : conn.getInputStream();
bodyStream = mp.get("content-encoding")!=null && mp.get("content-encoding").equalsIgnoreCase("gzip") ? new BufferedInputStream(new GZIPInputStream(dataStream)) : new BufferedInputStream(dataStream);
if(asFile!=null&&!asFile.trim().contentEquals(""))this.getFileFromUrlWIS(bodyStream,asFile);
else content = parseByteData(readToByteBuffer(bodyStream, 1024 * 1024), getCharsetFromContentType(conn.getContentType()));
catch(Exception e)Error.showError("Browser.getFromUrl() can't get data from url",e);
finally
if(bodyStream != null)bodyStream.close();
if(dataStream != null)dataStream.close();
conn.disconnect();
catch(Exception e)Error.showError("Browser.getFromUrl() can't get data from url",e);
mp.put("url", url);
mp.put("content", content.replaceAll(" ", " ")/*.replaceAll("<!--[\\s\\S]*?-->", "")*/.replaceAll("[\r\n\t]","").replaceAll("\\s+", " "));
curRedirect=0;
return mp;
【问题讨论】：
参考***.com/questions/5729806/encode-string-to-utf-8 你从哪里点击这个帖子请求一个 servlet 或一个 javascript/查询代码。？ 【参考方案1】：Java 中的字符串采用 UTF-16 格式。字节采用其他编码。字节通过网络发送。字符串不是。当您向网络发送字节时，使用 CharsetEncoder 获取所需编码中的字节，然后通过网络发送这些字节。您还没有展示实际通过网络发送数据的代码，因此不可能更精确。
【讨论】：
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