JVM property-Dfile.coding = UTF8还是 UTF-8?

我想知道将文件编码设置为 UTF-8的 Java 虚拟机(JVM)属性的值是什么。

我应该放 -Dfile.encoding=UTF8还是 -Dfile.encoding=UTF-8

145185 次浏览

It will be:

UTF8

See here for the definitions.

Both UTF8 and UTF-8 work for me.

If, running an Oracle HotSpot JDK 1.7.x, on a Linux platform where your locale suggests UTF-8 (e.g. LANG=en_US.utf8), if you don't set it on the command-line with -Dfile.encoding, the JDK will default file.encoding and the default Charset like this:

System.out.println(String.format("file.encoding: %s", System.getProperty("file.encoding")));
System.out.println(String.format("defaultCharset: %s", Charset.defaultCharset().name()));

... yields:

file.encoding: UTF-8
defaultCharset: UTF-8

... suggesting the default is UTF-8 on such a platform.

Additionally, if java.nio.charset.Charset.defaultCharset() finds file.encoding not-set, it looks for java.nio.charset.Charset.forName("UTF-8"), suggesting it prefers that string, although it is well-aliased, so "UTF8" will also work fine.

If you run the same program on the same platform with java -Dfile.encoding=UTF8, without the hypen, it yields:

file.encoding: UTF8
defaultCharset: UTF-8

... noting that the default charset has been canonicalized from UTF8 to UTF-8.

This is not a direct answer, but very useful if you don't have access to how java starts: you can set the environment variable JAVA_TOOLS_OPTIONS to -Dfile.encoding="UTF-8" and every time the jvm starts it will pick up that option.

[INFO] BUILD SUCCESS
Picked up JAVA_TOOL_OPTIONS: -Dfile.encoding=UTF8
Anyway, it works for me:)