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HomeJavajavaTutorialHow to determine the length of a string in Java development? See detailed code explanation

在Java中按字节获得字符串长度的两种方法,代码详解,例如:汉字中有生僻字:“掱”,结果计算出长度为2、UTF-8 长度3。

package cn.com.songjy.test;  

import java.io.UnsupportedEncodingException;  

/** 
 * 在Java中按字节获得字符串长度的两种方法 
 * 
 */  

public class App   
{  
    public static void main( String[] args ) throws UnsupportedEncodingException  
    {  
        String str = "只";  

        System.out.println(getWordCount(str));  
        System.out.println(getWordCountRegex(str));  
        System.out.println(getWordCountCode(str,"GBK"));  
        System.out.println(getWordCountCode(str,"UTF-8"));  
    }  

    /*由于Java是基于Unicode编码的,因此,一个汉字的长度为1,而不是2。 
     * 但有时需要以字节单位获得字符串的长度。例如,“123abc长城”按字节长度计算是10,而按Unicode计算长度是8。 
     * 为了获得10,需要从头扫描根据字符的Ascii来获得具体的长度。如果是标准的字符,Ascii的范围是0至255,如果是汉字或其他全角字符,Ascii会大于255。 
     * 因此,可以编写如下的方法来获得以字节为单位的字符串长度。*/  
    public static int getWordCount(String s)  
    {  
        int length = 0;  
        for(int i = 0; i < s.length(); i++)  
        {  
            int ascii = Character.codePointAt(s, i);  
            if(ascii >= 0 && ascii <=255)  
                length++;  
            else  
                length += 2;  

        }  
        return length;  

    }  

    /*基本原理是将字符串中所有的非标准字符(双字节字符)替换成两个标准字符(**,或其他的也可以)。这样就可以直接例用length方法获得字符串的字节长度了*/  
    public static  int getWordCountRegex(String s)  
    {  

        s = s.replaceAll("[^\\x00-\\xff]", "**");  
        int length = s.length();  
        return length;  
    }  

    /*按特定的编码格式获取长度*/  
    public static int getWordCountCode(String str, String code) throws UnsupportedEncodingException{  
        return str.getBytes(code).length;  
    }  
}

汉字中有生僻字:“掱”,结果计算出长度为2、UTF-8 长度3。

相关文章:

java判断中文字符串长度的简单实例

怎样判断一个字符,在另一个字符串中,判断字符,字符串

相关视频:

Java参考文档

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