在 Java 中直接使用Unicode 转码时会按照UTF-16LE 的方式拆分，并加上 BOM。 如果采用 UTF-16 拆分，在 Java 中默认采用带有 BOM 的 UTF-16BE 拆分。

 String a ="12dss显示,‘；（）中文只";StringBuffer b = new StringBuffer();for(int i = 0;i<a.length();i++){char t = a.charAt(i);String str = String.valueOf(t);if(str.getBytes().length ==2){b.append(str);}}System.out.println(b);

结果: 显示‘；（）中文只

java：获取字符串中第一个汉字和第一个汉字汉字标点符号的位置？

package tool;public class CopyCat
{public static void main ( String[] args ){String string = "adf你.？的说法sdf";String reg = "[\u4e00-\u9fa5]";int index = -1;if (string.matches (".*" + reg + ".*")){index = string.split (reg)[0].length ();}System.out.println (index);String regex = "[。，！？（）《》……、：——【】；’”‘“]";int ind = -1;if (string.matches (".*" + regex + ".*")){ind = string.split (regex)[0].length ();}System.out.println (ind);}
}

常用汉字 的unicode 码范围是：\u4e00-\u9fa5，下面一个例子是把中英文文档中的汉字提取出来的简单例子：

public class DrawEnglish{    private static String draw(String content)    {        StringBuffer english = new StringBuffer();

        String regex = "[\u4e00-\u9fa5。，？”“《》：！——-、]";        Pattern pattern = Pattern.compile(regex);        Matcher matcher = pattern.matcher(content);        while(matcher.find())        {            String temp = matcher.group();            english.append(temp);        }        return english.toString();    }    public static void drawEnglish(String path)    {        FileInputStream fr;        BufferedReader br;

        FileWriter fw;        BufferedWriter bw = null ;        try        {            fr = new FileInputStream(path);            br = new BufferedReader(new InputStreamReader(fr,"gb2312"));            fw = new FileWriter("new1.txt");            bw = new BufferedWriter(fw);            String str = null;            StringBuffer sb = new StringBuffer();            while((str = br.readLine()) != null)            {                sb.append(str + "\n");            }            String temp = draw(sb.toString());             bw.write(temp);

        } catch (FileNotFoundException e)        {            e.printStackTrace();        } catch (IOException e)        {            e.printStackTrace();        }        finally        {            try            {                if(bw != null) bw.close();            } catch (IOException e)            {                e.printStackTrace();            }        }    }    public static void main(String[] args)    {        drawEnglish("draw1.txt");    }}