最近发现erlang项目的配置文件某些中文显示会乱码,先说下配置文件的实现:

  1. 由file:consult/1读取配置的原始文件(一系列的erlang term),获取到原始的 erlang term
  2. 再转化成erlang 代码 然后再会写到文件。

问题就出在了转化erlang 代码这里,我们使用的是io_lib:format("~p",[data]) 来将erlang term 转化成字符串再回写到文件,而 io:format/2关于~p/~w在官方文档里面有这样的描述:

w
Writes data with the standard syntax. This is used to output Erlang terms. Atoms are printed within quotes if they contain embedded non-printable
characters, and floats are printed accurately as the shortest, correctly rounded string.
p
Writes the data with standard syntax in the same way as ~w, but breaks terms whose printed representation is longer than one line into many lines and
indents each line sensibly. It also tries to detect lists of printable characters and to output these as strings. The Unicode translation modifier is used for
determining what characters are printable.

也就是说,当我们使用io:format("~p",[Data])来显示数据时,会根据data的binary数据是否可以转化成unicode可打印字符来打印数据,这时候中文的unicode就会每个字节逐个转化unicode
因此:

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6> Bin1=unicode:characters_to_binary("书鬼").
<<228,185,166,233,172,188>>
7> io:format("~p",[Bin1]).
<<"书鬼">>ok
8> Bin2=unicode:characters_to_binary("书盲").
<<228,185,166,231,155,178>>
9> io:format("~p",[Bin2]).
<<228,185,166,231,155,178>>ok

48> io:format("~w",[Bin1]).
<<228,185,166,233,172,188>>ok
49> io:format("~w",[Bin2]).
<<228,185,166,231,155,178>>ok