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This article mainly introduces the relevant knowledge of "what is the processing method of characters in Java language". The editor shows you the operation process through an actual case. The operation method is simple, fast and practical. I hope this article "what is the processing method of characters in Java language" can help you solve the problem.

-Java is a programming language, a runtime system, a set of development tools, and an application programming interface (api). Java builds on C++ 's familiar and useful features, while removing C++ 's complex, dangerous and redundant elements. It is a safer, simpler, and easier to use language.

1. The character expression of Java

Characters are described differently in Java and C, and Java uses the 16-bit Unicode character set (the standard describes different characters in many languages), so the Java character is a 16-bit unsigned integer, and the character variable is used to hold a single character rather than a complete string.

-one character (character) is a single letter (letter), many letters form a word, a group of words form sentences, and so on. But for characters that contain information such as Chinese, it is not so simple.

-the basic char type of Java is defined as unsigned 16 bits, which is the only unsigned type in Java. The main reason for using 16-bit expression characters is to enable Java to support any Unicode character, which makes Java suitable for describing or displaying any language supported by Unicode, making it more portable. However, being able to support the display of strings in a certain language and being able to print strings in a certain language correctly are often two different issues. Because the main environment of the Oak (the original code name of Java) development team is the unix system and some systems derived from Unix, the most convenient and practical character set for developers is ISOLatin-1. Accordingly, this development group is Unix hereditary, which leads to the fact that Java's Imax O system is largely modeled on the flow concept of Unix, while in Unix system, each Imax O device is represented by a string of 8-bit streams. This practice, which is modeled on the Unix in the Icano system, makes the Java language have 16-bit Java characters, but only 8-bit input devices, which brings some shortcomings to Java. So wherever an Java string is read or written in 8 bits, there has to be a small piece of program code, called "hack", to map 8-bit characters to 16-bit Unicode, or 16-bit Unicode into 8-bit characters.

2. Problems and solutions

-We need to read information from a file, especially those containing Chinese information, and display the read information on the screen. Generally, we use the FileInputStream function to open the file and the readChar function to read characters. As follows:

Import java.io.*

Public class rf {

Public static void main (String args []) {

FileInputStream fis

DataInputStream dis

Char c

Try {

Fis = new FileInputStream ("xinxi.txt")

Dis = new DataInputStream (fis)

While (true) {

C = dis.readChar ()

System.out.print (c)

System.out.flush ()

If (c ='n') break

}

Fis.close ()

} catch (Exception e) {}

System.exit (0)

}

}

-but in fact, the output from running this program is a pile of useless garbled code. The reason why the contents of the xinxi.txt file cannot be output correctly is that the readChar function reads 16-bit Unicode characters while System.out.print outputs them as eight-bit ISO latin-1 characters.

-Java 1.1 introduces a new set of Readers and Writers interfaces to handle characters. We can use the InputStreamReader class instead of DataInputStream to process files. Modify the above program as follows:

Import java.io.*

Public class rf {

Public static void main (String args []) {

FileInputStream fis

InputStreamReader irs

Char ch

Try {

Fis = new FileInputStream ("xinxi.txt")

Irs = new InputStreamReader (fis)

While (true) {

Ch = (char) irs.read ()

System.out.print (c)

System.out.flush ()

If (ch = ='n') break

}

Fis.close ()

} catch (Exception e) {}

System.exit (0)

}

}

-this is the only way to correctly output the text in xinxi.txt (especially Chinese information). In addition, when the xinxi.txt file comes from different machines, that is, machines from different operating platforms (or different Chinese characters with different internal codes), for example, the file comes from the client (the client uploads the file to the server), and the operation of reading the information in the text is performed by the server. If you use the above program to achieve this function, you may still not be able to get the correct results. The reason is that the input coding conversion failed, and we need to make the following changes:

.

Int c1

Int jung0

StringBuffer str=new StringBuffer ()

Char lll [] [] = new char [20] [500]

String ll= ""

Try {

Fis = new FileInputStream ("fname.txt")

Irs = new InputStreamReader (fis)

C1=irs.read (lll [1], 05i 50)

While (lll [1] [j]! ='') {

Str.append (lll [1] [j])

J=j+1

}

Ll=str.toString ()

System.out.println (ll)

} catch (IOException e) {

System.out.println (e.toString ());}

.

-in this way, the output is correct. Of course, the above program is incomplete and just illustrates the solution.

This is the end of the content about "what is the method of dealing with characters in Java language". Thank you for reading. If you want to know more about the industry, you can follow the industry information channel. The editor will update different knowledge points for you every day.

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