blocks|key|1419968|text|如果我使用line.substring(0,2)，我会得到两个汉字"一二“。
|type|blockquote|depth|inlineStyleRanges|entityRanges|data|1419969|unstyled|1419970|所以你有两个角色。这就是你要的。索引0和1处的两个字符。|1419971|但是我希望，line.substring(0,2)的结果是"一“。
|1419972|1419973|如果你只想要一个角色，就要求一个角色。索引0处的字符。例如，line.substring(0,1)。|offset|length|style|CODE|1419974|entityMap^0|0|0|0|0|0|U|J|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|-4|5|C|7|R|8|@]|9|@]|A|$]]|$1|D|3|E|5|C|7|S|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|T|8|@]|9|@]|A|$]]|$1|H|3|-4|5|C|7|U|8|@]|9|@]|A|$]]|$1|I|3|J|5|C|7|V|8|@$K|W|L|X|M|N]]|9|@]|A|$]]|$1|O|3|-4|5|C|7|Y|8|@]|9|@]|A|$]]]|P|$]]

<blockquote>
 If I use line.substring(0,2), I get two chinese character "一二".
</blockquote>

So you got two characters. That's what you asked for. The two characters at index 0 and 1.

<blockquote>
 But I hope that, the result of line.substring(0,2) is "一".
</blockquote>

If you only want one character, ask for one character. The character at index 0. <code>line.substring(0,1)</code> for example.

blocks|key|1918776|text|从结果来看，我知道字符串中的汉字的长度是1，而不是2。
|type|blockquote|depth|inlineStyleRanges|entityRanges|data|1918777|unstyled|1918778|对，所以每个符号都是一个字符，所以这些"一二三四1234“字符串的长度是8。|1918779|为什么是12岁？|1918780|我的意思是，在我看来，"一二三四1234“的长度是12，而不是8。我可以使用子字符串(0，2)提取固定长度的字符。
|1918781|1918782|如果您知道所需字符的索引，则可以使用下面的代码：|1918783|String+s+=+"一二三四1234";
char+c+=+s.charAt(0);|code-block|syntax|javascript|1918784|因为方法subString从索引0到2创建了一个新的字符串|1918785|entityMap^0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|V|8|@]|9|@]|A|$]]|$1|B|3|-4|5|C|7|W|8|@]|9|@]|A|$]]|$1|D|3|E|5|C|7|X|8|@]|9|@]|A|$]]|$1|F|3|G|5|C|7|Y|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|Z|8|@]|9|@]|A|$]]|$1|J|3|-4|5|C|7|10|8|@]|9|@]|A|$]]|$1|K|3|L|5|C|7|11|8|@]|9|@]|A|$]]|$1|M|3|N|5|O|7|12|8|@]|9|@]|A|$P|Q]]|$1|R|3|S|5|C|7|13|8|@]|9|@]|A|$]]|$1|T|3|-4|5|C|7|14|8|@]|9|@]|A|$]]]|U|$]]

<blockquote>
 From the result , I know the length of a chinese character in String is one, not two.
</blockquote>

Thats right so every sign is a char, so the length of these "一二三四1234" string is 8

so why 12?

<blockquote>
 I mean that, in my eye the length of "一二三四1234" is 12, not 8.I can use substring(0,2) to extract fixed length character.
</blockquote>

if you know the index of the char you want you can use the code below instead:

<pre><code>String s = "一二三四1234";
char c = s.charAt(0);
</code></pre>

Because the method subString creates a new String from the index 0 to 2

blocks|key|1918840|text|Java使用unicode作为内部字符集，因此任何char类型都是unicode.And+java.lang.String由字符组成。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1918841|当您从读取器获得字符串时，文件的字节内容已经根据文件的编码被转换为字符。|1918842|line.substring(0，2)生成一个新的字符串，它将返回行的两个字符，这就是您已经得到的！|1918843|我猜“在我眼中长度”的意思是指在像UltraEdit这样的文本编辑器中，也许编辑器只是显示文件中字节的位置。|1918844|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|J|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|K|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|L|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|M|8|@]|9|@]|A|$]]|$1|H|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|I|$]]

Java use unicode as internal charset, so any char type is unicode.And java.lang.String is consist of chars. 

When you get string from reader,the bytes content of file is already translated to chars base on encoding of file.

line.substring(0, 2) result in a new string with fisrt two chars of the line to be returned,that's what you already got!

I guess "in my eye the length " mean by you see that in a text editor like UltraEdit,maybe
editor just show the position of bytes in the file

blocks|key|1918857|text|首先，您需要使用中文编码(如GBK、GB2312等)对文件进行解码。|type|ordered-list-item|depth|inlineStyleRanges|entityRanges|data|1918858|将行读入字节数组，然后使用中文编码将该字节数组转换为字符串。
FileInputStream+fileStream=new+FileInputStream(“sometext.txt”)；byte[]+buf=new+byte12；byte[]+line=reader.read(buf)；byte[]+byteRange=Arrays.copyOfRange(allBytes，0，2)；String+chineseString=new+String(byteRange，Charset.forName("GBK"))；|1918859|unstyled|1918860|1918861|这样你只会得到一个汉字。从GBK到UTF-8的转换只有一个步骤.|1918862|哦，太棒了！对以前方法的改进。|1918863|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|N|8|@]|9|@]|A|$]]|$1|D|3|-4|5|E|7|O|8|@]|9|@]|A|$]]|$1|F|3|-4|5|E|7|P|8|@]|9|@]|A|$]]|$1|G|3|H|5|E|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|E|7|R|8|@]|9|@]|A|$]]|$1|K|3|-4|5|E|7|S|8|@]|9|@]|A|$]]]|L|$]]

<ol>
<li>First you need to decode the file using chinsese encodings, such as GBK, GB2312, etc. </li>
<li>Read the line into byte array and then convert that byte array into string using chinese encodings.

<pre><code>FileInputStream fileStream=new FileInputStream(New 
File("sometext.txt"));
byte[] buf=new byte[12];
byte[] line=reader.read(buf);
byte[] byteRange=Arrays.copyOfRange(allBytes,0,2));
String chineseString=new String(byteRange,Charset.forName("GBK")); 
</code></pre></li>
</ol>

This way you will only get 1 chinese character. There are only 1 step of conversion from GBK to UTF-8. 

Oh, yeah! An improvement from the previous method.

If I use BufferReader to read a line, I can get a string of a line.
The code is this :

<pre><code>FileInputStream fs = new FileInputStream("E:\\tmp\\aaa.txt");
BufferedReader br = new BufferedReader(new InputStreamReader(fs));


String line = null; 
while ((line = br.readLine()) != null) { 
 System.out.println(line.length() + " " +line.substring(0, 2);
}
</code></pre>

The contents of aaa.txt is :

<pre><code>一二三四1234
</code></pre>

so. the result of running the code is :

<pre><code>8 一二
</code></pre>

From the result , I know the length of a chinese character in String is one, not two.

So If I use line.substring(0,2), I get two chinese character "一二". 
But I hope that, the result of line.substring(0,2) is "一". 

I mean that, in my eye the length of "一二三四1234" is 12, not 8.I can use substring(0,2) to 
extract fixed length character.

Thanks in advance.

How to read fixed length character using BufferReader or other method?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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如果我使用BufferReader读取一行，就可以得到一行的字符串。守则是：FileInputStream fs = new FileInputStream("E:\\tmp\\aaa.txt");BufferedReader br = new BufferedReader(new InputStreamReader(...

问如何使用BufferReader或其他方法读取固定长度字符？
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问如何使用BufferReader或其他方法读取固定长度字符？EN