如何在 Java 中添加 UTF-8 BOM？
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How to add a UTF-8 BOM in Java?
提问by Fadd
I have a Java stored procedure which fetches record from the table using Resultsetobject and creates a CS Vfile.
我有一个 Java 存储过程，它使用Resultset对象从表中获取记录并创建一个 CS Vfile。
BLOB retBLOB = BLOB.createTemporary(conn, true, BLOB.DURATION_SESSION);
retBLOB.open(BLOB.MODE_READWRITE);
OutputStream bOut = retBLOB.setBinaryStream(0L);
ZipOutputStream zipOut = new ZipOutputStream(bOut);
PrintStream out = new PrintStream(zipOut,false,"UTF-8");
out.write('\ufeff');
out.flush();
zipOut.putNextEntry(new ZipEntry("filename.csv"));
while (rs.next()){
out.print("\"" + rs.getString(i) + "\"");
out.print(",");
}
out.flush();
zipOut.closeEntry();
zipOut.close();
retBLOB.close();
return retBLOB;
But the generated CSV file doesn't show the correct German character. Oracle database also has a NLS_CHARACTERSETvalue of UTF8.
但是生成的 CSV 文件没有显示正确的德语字符。Oracle 数据库也有一个NLS_CHARACTERSETUTF8 值。
Please suggest.
请建议。
采纳答案by axtavt
To write a BOM in UTF-8 you need PrintStream.print(), not PrintStream.write().
要在 UTF-8 中编写 BOM，您需要PrintStream.print()，而不是PrintStream.write().
Also if you want to have BOM in your csvfile, I guess you need to print a BOM after putNextEntry().
另外，如果您想在csv文件中包含 BOM ，我想您需要在putNextEntry().
回答by Stephen C
I think that out.write('\ufeff');should actually be out.print('\ufeff');.
我认为out.write('\ufeff');实际上应该是out.print('\ufeff');。
According the javadoc, the write(int)method actually writes a byte ... without any character encoding. So out.write('\ufeff');writes the byte 0xff. By contrast, the print(char)method encodes the character as one or bytes using the stream's encoding, and then writes those bytes.
根据javadoc，该write(int)方法实际上写入一个字节......没有任何字符编码。所以out.write('\ufeff');写字节0xff。相比之下，该print(char)方法使用流的编码将字符编码为一个或多个字节，然后写入这些字节。
回答by astro
BufferedWriter out = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(...), StandardCharsets.UTF_8));
out.write('\ufeff');
out.write(...);
This correctly writes out 0xEF 0xBB 0xBF to the file, which is the UTF-8 representation of the BOM.
这正确地将 0xEF 0xBB 0xBF 写入文件，这是 BOM 的 UTF-8 表示。
回答by Rocio
In my case it works with the code:
就我而言，它适用于以下代码：
PrintWriter out = new PrintWriter(new File(filePath), "UTF-8");
out.write(csvContent);
out.flush();
out.close();
回答by Christopher Schultz
Just in case people areusing PrintStreams, you need to do it a little differently. While a Writerwill do some magic to convert a single byte into 3 bytes, a PrintStreamrequires all 3 bytes of the UTF-8 BOM individually:
万一人都使用PrintStreamS，你需要以不同的方式做到这一点。虽然 aWriter可以将单个字节转换为 3 个字节，但 aPrintStream需要单独使用 UTF-8 BOM 的所有 3 个字节：
// Print utf-8 BOM
PrintStream out = System.out;
out.write('\ufeef'); // emits 0xef
out.write('\ufebb'); // emits 0xbb
out.write('\ufebf'); // emits 0xbf
Alternatively, you can use the hex values for those directly:
或者，您可以直接使用十六进制值：
PrintStream out = System.out;
out.write(0xef); // emits 0xef
out.write(0xbb); // emits 0xbb
out.write(0xbf); // emits 0xbf
