Java String.getBytes（charsetName）vs String.getBytes（Charset object） [英] Java String.getBytes( charsetName ) vs String.getBytes ( Charset object )
问题描述
我需要使用UTF-8编码将字符串编码为字节数组。我使用谷歌番石榴，它有Charsets类已经定义的Charset实例为UTF-8编码。我有2种方法：
I need to encode a String to byte array using UTF-8 encoding. I am using Google guava, it has Charsets class already define Charset instance for UTF-8 encoding. I have 2 ways to do:
-
String.getBytes（charsetName）
String.getBytes( charsetName )
try {
byte[] bytes = my_input.getBytes ( "UTF-8" );
} catch ( UnsupportedEncodingException ex) {
}
String.getBytes（Charset object）
String.getBytes( Charset object )
// Charsets.UTF_8 is an instance of Charset
byte[] bytes = my_input.getBytes ( Charsets.UTF_8 );
我的问题是，它们返回相同的结果。对于方式2 - 我不必把try / catch！我来看看Java源代码，我看到的方式1和方式2的实现方式不同。
My question is which one I should use? They return the same result. For way 2 - I don't have to put try/catch! I take a look at the Java source code and I see that way 1 and way 2 are implemented differently.
任何人都有什么想法？
推荐答案
如果你要使用字符串文字（例如UTF-8）...你不应该。请改用第二个版本，并从 StandardCharsets （在这种情况下， StandardCharsets.UTF_8 ）。
If you are going to use a string literal (e.g. "UTF-8") ... you shouldn't. Instead use the second version and supply the constant value from StandardCharsets (specifically, StandardCharsets.UTF_8, in this case).
第一个版本在字符集为动态时使用。这将是这样的情况，当你不知道什么是字符集在编译时;它由最终用户提供，从配置文件或系统属性等读取。
The first version is used when the charset is dynamic. This is going to be the case when you don't know what the charset is at compile time; it's being supplied by an end user, read from a config file or system property, etc.
在内部，两个方法都调用 StringCoding .encode（）。 encode（）的第一个版本只是首先通过提供的名称查找 Charset ，并抛出异常if该字符集是未知/不可用。
Internally, both methods are calling a version of StringCoding.encode(). The first version of encode() is simply looking up the Charset by the supplied name first, and throwing an exception if that charset is unknown / not available.
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