java读写磁盘文件

package test;

import java.io.*;
import java.util.*;

 

public class FileReadWrite {

 /**
  * 描述：readFile
  *
  * @param dir
  * @return
  * @throws IOException
  * @CreateOn Jul 28, 2008 2:16:23 PM
  * @author chun_chang
  */
 public StringBuffer readFile(String dir) throws IOException {
  StringBuffer buffer = null;
  try {
   buffer = new StringBuffer();
   InputStream fis = new FileInputStream(dir);
   BufferedReader reader = new BufferedReader(new InputStreamReader(fis));

   String line = null;// 用来保存每行读取的内容
   line = reader.readLine(); // 读取第一行
   while (line != null) { // 如果 line 为空说明读完了
    buffer.append(line); // 将读到的内容添加到 buffer 中
    buffer.append("/n"); // 添加换行符
    line = reader.readLine(); // 读取下一行
   }
   System.out.println(buffer); // 将读到 buffer 中的内容写出来
   fis.close();
  } catch (FileNotFoundException e) {
   e.printStackTrace();
  }
  return buffer;
 }

 

 /**
  * 描述：writeFile
  *
  * @param dir
  * @param content
  * @param flag
  *            true：追加，false：覆盖
  * @throws IOException
  * @CreateOn Jul 28, 2008 3:58:07 PM
  * @author chun_chang
  */
 public void writeFile(String dir, String content, boolean flag) throws IOException {
  try {
   // 文件的追加或修改
   OutputStream fos = new FileOutputStream(dir, flag);
   OutputStreamWriter osw = new OutputStreamWriter(fos);

   osw.write(content, 0, content.length());
   osw.flush();
   fos.close();
  } catch (FileNotFoundException e) {
   // 文件不存在的时候
   File write = new File(dir);
   BufferedWriter bw = new BufferedWriter(new FileWriter(write, flag));
   bw.write(content + "/r/n"); // 只适用Windows系统
   bw.close();
  }
 }

 

 /**
  * 描述：sort 冒泡排序(降序)
  * @param src
  * @CreateOn Jul 29, 2008  9:49:15 AM
  * @author chun_chang
  */
 public void sort(int[] src) {
  int i, m = 0;
  for (i = 0; i < src.length - 1; i++) {
   for (m = i + 1; m < src.length; m++) {
    if (src[i] < src[m]) {
     int temp = src[i];
     src[i] = src[m];
     src[m] = temp;
    }
   }
  }
 }

 

 /**
  * 描述：strToInt String[]转化为int[]数组
  * @param arrs
  * @return
  * @CreateOn Jul 29, 2008  9:47:37 AM
  * @author chun_chang
  */
 public int[] strToInt(String[] arrs) {
  int[] arri = new int[arrs.length];
  for (int i = 0; i < arrs.length; i++) {
   arri[i] = Integer.parseInt(arrs[i]);
  }
  return arri;
 }

 

 

 /**
  * 描述：intToStr int[]转化为String[]数组
  * @param arri
  * @return
  * @CreateOn Jul 29, 2008  9:47:34 AM
  * @author chun_chang
  */
 public String[] intToStr(int[] arri) {
  String[] arrs = new String[arri.length];
  for (int i = 0; i < arri.length; i++) {
   arrs[i] = String.valueOf(arrs[i]);
  }
  return arrs;
 }

 

 

 /**
  * 描述：main
  *
  * @param args
  * @CreateOn Jul 28, 2008 1:58:24 PM
  * @author chun_chang
  */
 public static void main(String[] args) {
  FileReadWrite frw = new FileReadWrite();
  String result = null;
  String dirr = "C://in.txt";
  String dirw = "C://out.txt";
  try {
   result = frw.readFile(dirr).toString();
   // frw.writeFile(dirw, content);//直接写入content
   String str = result.replaceAll("/n", " ");//回车符替换为空格
   String array[] = str.split(" ");//按空格 划分为数组
   int[] arri = frw.strToInt(array);
   frw.sort(arri);//冒泡排序(降序)
   //Arrays.sort(arri)//util包自带排序(升序)
   frw.writeFile(dirw, Arrays.toString(arri), false);
  } catch (IOException e) {
   e.printStackTrace();
  }

 }

}