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| import java.io.BufferedReader;
 
 import java.io.FileNotFoundException;
 import java.io.FileReader;
 import java.io.FileWriter;
 import java.io.IOException;
 import java.io.Writer;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 
 
 
 
 
 public class Test8 {
 
 /**
 * @param args
 */
 
 public static void Print() throws FileNotFoundException,IOException{
 BufferedReader br = new BufferedReader(new FileReader("E://项目/exam/src/com/itheima/a.txt"));
 
 Writer fw = null;
 
 List<Character> arrayList = new ArrayList<Character>();
 //把文件中的字符存进ArrayList集合中
 int ch;
 while((ch=br.read())!=-1){
 char c = (char)ch;
 arrayList.add(c);
 
 }
 //把ArrayList集合中的值转换成数组
 Object[] sd = arrayList.toArray();
 //把数组中的值以升序进行排序
 Arrays.sort(sd);
 
 String[] sb = new String[sd.length];
 //把数组中的值放入一个字符串中
 String s =new String();
 
 for(int i=0;i<sd.length;i++){
 sb[i]=sd[i].toString();
 s=s.concat(sb[i].trim());
 
 }
 try{
 //把字符串的值写入b.txt文件中
 fw = new FileWriter("E://项目/exam/src/com/itheima/b.txt");
 fw.write(s);
 }catch(IOException e){
 e.printStackTrace();
 }finally{
 try{
 if(null != fw){
 fw.close();
 }
 }catch(IOException e){
 e.printStackTrace();
 }
 
 }
 
 
 }
 
 
 public static void main(String[] args) {
 // TODO Auto-generated method stub
 try {
 Print();
 } catch (FileNotFoundException e) {
 // TODO Auto-generated catch block
 e.printStackTrace();
 } catch (IOException e) {
 // TODO Auto-generated catch block
 e.printStackTrace();
 }
 
 }
 
 }
 
 
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