Java determines whether it is a Chinese character or whether it has a Chinese character

Java checks whether it is a Chinese character and whether it has a Chinese character

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Java code

1. PublicBooleanVd (String str ){
3. Char[] Chars = Str. tochararray ();
4. BooleanIsgb2312 =False;
5. For(IntI = 0; I <chars. length; I ++ ){
6. Byte[] Bytes = ("" + chars [I]). getbytes ();
7. If(Bytes. Length = 2 ){
8. Int[] Ints =NewInt[2];
9. Ints [0] = bytes [0] & 0xff;
10. Ints [1] = bytes [1] & 0xff;
11. If(Ints [0]> = 0x81 & ints [0] <= 0xFE & ints [1]> = 0x40 & ints [1] <= 0xFE) {
12. IsGB2312 =True;
13. Break;
14. }
15. }
16. }
17. ReturnIsgb2312;
18. }

First, import java. util. regex. Pattern and java. util. regex. Matcher.
The two packages are followed by the code

Determines whether it is a number.

Java code

1. PublicBooleanIsnumeric (string Str)
2. {
3. Pattern pattern = pattern. Compile ("[0-9] *");
4. Matcher isnum = pattern. matcher (STR );
5. If(! Isnum. Matches ()){
6. ReturnFalse;
7. }
8. ReturnTrue;
9. }
11. Java. Lang. character. isdigit (CH [0])

Java code

1. PublicStaticVoidMain (string [] ARGs ){
2. IntCount = 0;
3. String regEx = "[\ u4e00-\ u9fa5]";
4. // System. out. println (regEx );
5. String str = "Chinese fdas ";
6. // System. out. println (str );
7. Pattern p = Pattern. compile (regEx );
8. Matcher m = p. matcher (str );
9. While(M. find ()){
10. For(IntI = 0; I <= m. groupCount (); I ++ ){
11. Count = count + 1;
12. }
13. }
14. System. out. println ("Total" + count + "count ");
15. }

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Method for Determining whether a java String contains Chinese Characters

Java uses Unicode-encoded char variables in the range of 0-65535 unsigned values, which can represent
65536 characters. Basically, all the characters on Earth can be included. In reality, we want to determine whether a character is a Chinese character, or whether the characters in a string contain Chinese characters to meet business needs
Evaluate, the String class has such a method to get its character length (). See the following example,

Java code

1. String s1 = "I am a Chinese ";
2. String s2 = "imchinese ";
3. String s3 = "im Chinese ";
4. System. out. println (s1 + ":" +NewString (s1). length ());
5. System. out. println (s2 + ":" +NewString (s2). length ());
6. System. out. println (s3 + ":" +NewString (s3). length ());

OUTPUT:
I am a Chinese: 5
Imchinese: 9
Im Chinese: 5
As you can see, if the string contains double-byte characters, java will encode each character in double-byte format. If it is a single-byte character, it will be encoded in single-byte format.
So according to the above rules, combined with a QQ nickname? G tea? I Zhuhai elder brother's prompt is resolved by judging whether the string length is the same as the character byte length to determine whether there are double byte characters

Java code

1. System. out. println (s1.getBytes (). length = s1.length ())? "S1 has no Chinese characters": "s1 has Chinese characters ");
2. System. out. println (s2.getBytes (). length = s2.length ())? "S2 has no Chinese characters": "s2 has Chinese characters ");
3. System. out. println (s3.getBytes (). length = s3.length ())? "S3 has no Chinese characters": "s3 has Chinese characters ");