java 将 JSON 文件写入为 UTF-8 编码
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Write JSON file as UTF-8 encoded
提问by Jon
I am writing a method that writes some JSON to a file, which works fine. However, although I have set the output to be UTF-8, Oxygenfails to read a pound and euro sign.
我正在编写一种将一些 JSON 写入文件的方法，该方法工作正常。但是，尽管我已将输出设置为 UTF-8，但Oxygen无法读取英镑和欧元符号。
Java code:
爪哇代码：
Path logFile = Paths.get(this.output_folder + "/" + file.getName().split("\.")[0] + ".json");
try (BufferedWriter writer = Files.newBufferedWriter(logFile, StandardCharsets.UTF_8)) {
File fileDir = new File("test.json");
Writer out = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(fileDir), "UTF8"));
ObjectMapper mapper = new ObjectMapper();
writer.write(mapper.writerWithDefaultPrettyPrinter().writeValueAsString(all_questions));
}
"all_questions" is an arraylist of Question objects, which is being printed as a formatted piece of JSON by an ObjectMapper.
“all_questions”是一个 Question 对象的数组列表，它被 ObjectMapper 打印为格式化的 JSON 片段。
Some sample JSON with the pound sign looks like this:
一些带有英镑符号的示例 JSON 如下所示：
{
"name" : "RegExRule",
"field" : "Q039_4",
"rules" : [ ],
"fileName" : "s1rules_england_en.xml",
"error" : null,
"pattern_match" : {
"$record.ApplicationData.SiteVisit.VisitContactDetails.ContactOther.PersonName.PersonGivenName" : "^[\u0000-\u005F\u0061-\u007B\u007d-\u007f￡]*$"
}
}
However, that is displayed in notepad++. In Oxygen, it is displayed as follows:
但是，它显示在记事本++中。在Oxygen中，显示如下：
"pattern_match" : {
"$record.ApplicationData.SiteVisit.VisitContactDetails.ContactOther.PersonName.PersonGivenName" : "^[\u0000-\u005F\u0061-\u007B\u007d-\u007f?￡a??]*$"
}
回答by Remy Lebeau
When constructing the OutputStreamWriterobject, you need to use "UTF-8"as the charset name, not "UTF8":
构造OutputStreamWriter对象时，您需要使用"UTF-8"作为字符集名称，而不是"UTF8"：
new OutputStreamWriter(..., "UTF-8")
Alternatively, use StandardCharsets.UTF_8instead:
或者，StandardCharsets.UTF_8改用：
new OutputStreamWriter(..., StandardCharsets.UTF_8)
Java does not generally support reading/writing BOMs, so if you want your JSON file to have a UTF-8 BOM then you will have to write one manually:
Java 通常不支持读/写 BOM，因此如果您希望 JSON 文件具有 UTF-8 BOM，那么您必须手动编写一个：
Writer out = ...;
out.write("\uFEFF");
out.write(... json content here ...);
FYI, PrintWritercan manage the OutputStreamWriterand FileOutputStreamobjects for you:
仅供参考，PrintWriter可以为您管理OutputStreamWriter和FileOutputStream对象：
Writer out = new PrintWriter(fileDir, "UTF-8");
Or:
或者：
Writer out = new PrintWriter("test.json", "UTF-8");
Lastly, why are you creating a BufferedWriterusing Files.newBufferedWriter()only to ignore it and create a secondary BufferedWritermanually? Why not just use the BufferedWriterthat you already have:
最后，你为什么要创建一个BufferedWriterusing Files.newBufferedWriter()only 来忽略它并BufferedWriter手动创建一个辅助？为什么不直接使用BufferedWriter你已经拥有的：
Path logFile = Paths.get(this.output_folder + "/" + file.getName().split("\.")[0] + ".json");
try (BufferedWriter writer = Files.newBufferedWriter(logFile, StandardCharsets.UTF_8)) {
writer.write("\uFEFF");
ObjectMapper mapper = new ObjectMapper();
writer.write(mapper.writerWithDefaultPrettyPrinter().writeValueAsString(all_questions));
}
