1: If s.getBytes() takes no parameters, it will call the default encoding of jdk (yours may be utf-8) to decode the string into byte[], and then you use the gbk encoding method to re-encode the byte[] into string, so garbled characters will appear.

2.s.getBytes('gbk') You decode the string according to the gbk method and then re-encode it using the gbk method, so there will be no garbled characters.

What you said above is correct. I would like to add that the default encoding of jdk is file.encoding中指定的编码，可以通过Dfile.encoding=GBKThis is how to modify the default encoding of JVM.

To add some coding and decoding knowledge, if the Chinese character "Hello" is to be transmitted in the computer, it must be converted into binary. How to convert to binary is what is mentioned heredecoding.
There are many encoding methods, such as the Unicode character set. This character set contains numbers corresponding to various symbols. For example, you is represented by 2345, which is then converted into binary in a certain way (you can find the specific process online for specific conversion methods). Unicode字符集。这个字符集里面就是各种符号对应的数字，比如你用2345来表示，然后按照一定的方式转换的二进制（具体怎么转换可以网上找一下具体过程）。
接收到这一串二进制数，怎么转为汉字就是这里说的编码。编码需要按照一定的方式去解才能得到正确的字符对应关系，比如你的二进制为0101010010，需要按照utf-8的方式去编码才能得到你After receiving this string of binary numbers, how to convert them into Chinese characters is the