Question

编辑：我对charcter进行了硬编码并使用repsonse编写器来编写它，它仍然存在 Knigsberger

response.setCharacterEncoding("UTF-8");

            response.setContentType(contentType);
            //if(contentType!=null)response.setHeader("Content-Type",contentType);
            Writer writer = response.getWriter();//new OutputStreamWriter(response.getOutputStream(),"UTF-8");
            System.err.println("character encoding is "+response.getCharacterEncoding());


            writer.write("Königsberger ");
            writer.flush();

编辑：我在调用getWriter（）之前尝试了setContentType和setContentEncoding，但输出仍然没有区别：

        if(res.length()>0){
            //pw.write(res);
            response.setCharacterEncoding("UTF-8");
            response.setContentType(contentType);
            //if(contentType!=null)response.setHeader("Content-Type",contentType);
            Writer writer = response.getWriter();//new OutputStreamWriter(response.getOutputStream(),"UTF-8");
            System.err.println("character encoding is "+response.getCharacterEncoding());


            writer.write(res);
            writer.flush();
        }

我正在阅读一些德语字符然后从java servlet输出xml，这是我在UTF8中读取它们的方式：

int len=0;
        byte[]buffer=new byte[1024];
        OutputStream os = sock.getOutputStream();
        InputStream is = sock.getInputStream();
        query += "\r\n";
        os.write(query.getBytes("UTF8"));//iso8859_1"));

            do{
                len = is.read(buffer);
             if (len>0) { 
                 if(outstring==null)outstring=new StringBuffer();
                 outstring.append(new String(buffer,0,len, "UTF8"));
             }
           }while(len>0);
System.out.println(outstring);

System.out正确输出字符串： Königsberger

然而，当我使用charset = UTF-8从我的servletResponse重新发送此字符串时它变得狼吞虎咽：K nigsberger

private void outputResponse(String res, HttpServletRequest request,
            HttpServletResponse response) throws IOException {
        String outputFormat = getOutputFormat(request);
        String contentType=null;
        PrintWriter pw = response.getWriter();
        //response.setCharacterEncoding("UTF-8");
        System.err.println("output "+res);

        contentType= "text/xml; charset=UTF-8";
        res="<?xml version=\"1.0\" encoding=\"utf-8\"?>" + res;

        if(contentType!=null)response.setHeader("Content-Type",contentType);
        if(res.length()>0){
            pw.write(res);
        }
        pw.flush();

    }

Answer 1

do{
  len = is.read(buffer);
  if (len>0) { 
    if(outstring==null) outstring=new StringBuffer();
    outstring.append(new String(buffer,0,len, "UTF8"));
  }
}while(len>0);

这不是解码UTF-8的好方法，因为字符在缓冲区边界（details here）上可能会被破坏。 UTF-8是可变宽度编码，因此字符需要1到4个字节才能存储。如果它正常运作，你就会变得幸运。最好使用Reader / Writer类（details here）进行编码和解码。

我认为您需要在致电getWriter之前致电setContentType或setCharacterEncoding。我不认为直接致电setHeader就足够了。

此servlet代码将正确编码并将样本字符串作为UTF-8数据传输：

  @Override
  protected void doGet(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {
    response.setContentType("text/xml; charset=UTF-8");
    PrintWriter pw = response.getWriter();
    pw.write("<?xml version=\"1.0\" encoding=\"UTF-8\"?>");
    pw.write("<data>K\u00F6nigsberger</data>");
    pw.flush();
    pw.close();
  }

请注意，我使用转义序列\u00F6发出字符U + 00F6（ö）以确保我不会在文本编辑器或编译期间损坏字符过程（see here for more details）。

数据是否可能在客户端上被误解？使用十六进制编辑器检查输出。

编码为UTF-8，"K\u00F6nigsberger"应该成为字节序列：

4b c3 b6 6e 69 67 73 62 65 72 67 65 72

...字符U + 00F6（ö）变为c3 b6。您可以使用这样的代码来检查您的值：

  public static void main(String[] args) throws IOException {
    String konigsberger = "K\u00F6nigsberger";
    dumpHex(System.out, konigsberger.getBytes("UTF-8"));
  }

  private static void dumpHex(PrintStream out, byte[] data) {
    for (byte b : data) {
      out.format("%02x ", b);
    }
    out.println();
  }

Answer 2

您应该按照示例操作，让servlet response了解要遵循的编码：

response.setContentType("text/html; charset=UTF-8");
response.setCharacterEncoding("UTF-8");
ServletOutputStream out =response.getOutputStream();
out.write(output.getBytes("UTF-8"));

Answer 3

你总是可以使用这样的实体：

<test>
&#228;
&#252;
&#229;
</test>

得到：

<test>
ä
ü
å
</test>

也许不完全是你想要的，但是一个很好的解决方法。您可以使用utf8-chartable.de等网站查找所需的值。

Answer 4

我也遇到了同样的问题。我刚刚完成了以下事情并且工作正常：

byte[] k =xml.getBytes(UTF8_CHARSET); // xml is the string with unicode content.  getBytes("UTF-16") encodes given String into a sequence of bytes and returns an array of bytes. you can use xml.getBytes(UTF-16); for utf-16 encoding

response.setContentType("text/xml");
response.setContentLength(k.length);
response.getOutputStream().write(k);
response.getOutputStream().flush();
response.getOutputStream().close();

xml输出中的nolatin字符

4 个答案: