Java String.getBytes( charsetName ) vs String.getBytes ( Char

Java String.getBytes( charsetName ) vs String.getBytes ( Charset object )(Java String.getBytes( charsetName ) vs String.getBytes ( Charset 对象))

问题描述

我需要使用 UTF-8 编码将字符串编码为字节数组.我正在使用谷歌番石榴，它的 Charsets 类已经为 UTF-8 编码定义了 Charset 实例.我有两种方法:

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:

1. String.getBytes( charsetName )

1. String.getBytes( charsetName )

try {        
    byte[] bytes = my_input.getBytes ( "UTF-8" );
} catch ( UnsupportedEncodingException ex) {

}

// Charsets.UTF_8 is an instance of Charset    

byte[] bytes = my_input.getBytes ( Charsets.UTF_8 );

我的问题是我应该使用哪一种?它们返回相同的结果.对于方式 2 - 我不必放置 try/catch！我查看了 Java 源代码，发现方式 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.

有人有什么想法吗?

推荐答案

如果您打算使用字符串字面量(例如UTF-8")……您不应该使用.而是使用第二个版本并提供来自 的常量值StandardCharsets(特别是在本例中为 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).

当字符集是动态时使用第一个版本.当您在编译时不知道字符集是什么时，就会出现这种情况；它由最终用户提供，从配置文件或系统属性等中读取.

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，这两种方法都调用了一个版本的 StringCoding.encode().encode() 的第一个版本只是首先通过提供的名称查找 Charset，如果该字符集未知/不可用则抛出异常.

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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