java判断字符串编码详解编程语言

public static String getEncoding(String str){ 
        String encoding = "UTF-8"; 
        try { 
            if (str.equals(new String(str.getBytes(),encoding))) { 
                return encoding; 
            } 
        } catch (UnsupportedEncodingException e) { 
            // TODO Auto-generated catch block 
            e.printStackTrace(); 
        } 
 
        encoding = "GBK"; 
        try { 
            if (str.equals(new String(str.getBytes(),encoding))) { 
                return encoding; 
            } 
        } catch (UnsupportedEncodingException e) { 
            // TODO Auto-generated catch block 
            e.printStackTrace(); 
        } 
 
        encoding = "ISO-8859-1"; 
        try { 
            if (str.equals(new String(str.getBytes(),encoding))) { 
                return encoding; 
            } 
        } catch (UnsupportedEncodingException e) { 
            // TODO Auto-generated catch block 
            e.printStackTrace(); 
        } 
 
        encoding = "GB2312"; 
        try { 
            if (str.equals(new String(str.getBytes(),encoding))) { 
                return encoding; 
            } 
        } catch (UnsupportedEncodingException e) { 
            // TODO Auto-generated catch block 
            e.printStackTrace(); 
        } 
 
        return null; 
    }