缓冲

来源：互联网发布：数据库数字类型编辑：程序博客网时间：2024/04/28 12:44

package org.java.io;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

public class BufferedWriterDemo {

   /**
   * Buffered是流的一个缓冲技术，主要用于来提高，流的读写的效率，
   * 底层的实现，也就是封装了一个数组的对象来操作
   * ,既然是对流的一个高效，性能的优化，所以要先有流，后又缓冲
   */
   public static void main(String[] args) {

       copy1("d:\\test.txt", "f:\\tt.txt");
   }

   public static void copy(String srcFileName, String targetFileName) {
       BufferedReader reader=null;
       BufferedWriter writer=null;
       int len=0;
       char[] chars=new char[1024];

       File srcFile=new File(srcFileName);
       if(!srcFile.exists())
           return;
       try {
           reader=new BufferedReader(new FileReader(srcFile));
           File targetFile=new File(targetFileName);
           if(!targetFile.exists())
               try {
                   targetFile.createNewFile();
               } catch (IOException e) {
                   // TODO Auto-generated catch block
                   e.printStackTrace();
               }

           writer=new BufferedWriter(new FileWriter(targetFile));
           while((len=reader.read(chars))!=-1){
               writer.write(chars, 0, len);
               //注意在用缓存技术的时候，每次必须刷新
               writer.flush();
           }



       } catch (FileNotFoundException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (IOException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }finally{
           try {
               if(reader!=null)
                   reader.close();
           } catch (IOException e) {
               // TODO Auto-generated catch block
               e.printStackTrace();
           }
           try {
               if(writer!=null)
                   writer.close();
           } catch (IOException e) {
               // TODO Auto-generated catch block
               e.printStackTrace();
           }
       }
   }

   public static void copy1(String srcFileName, String targetFileName) {
       BufferedReader reader=null;
       BufferedWriter writer=null;
       String buf=null;

       File srcFile=new File(srcFileName);
       if(!srcFile.exists())
           return;
       try {
           reader=new BufferedReader(new FileReader(srcFile));
           File targetFile=new File(targetFileName);
           if(!targetFile.exists())
               try {
                   targetFile.createNewFile();
               } catch (IOException e) {
                   // TODO Auto-generated catch block
                   e.printStackTrace();
               }

           writer=new BufferedWriter(new FileWriter(targetFile));
           while((buf=reader.readLine())!=null){
               writer.write(buf);
               writer.newLine();
               //注意在用缓存技术的时候，每次必须刷新
               writer.flush();
           }



       } catch (FileNotFoundException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (IOException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }finally{
           try {
               if(reader!=null)
                   reader.close();
           } catch (IOException e) {
               // TODO Auto-generated catch block
               e.printStackTrace();
           }
           try {
               if(writer!=null)
                   writer.close();
           } catch (IOException e) {
               // TODO Auto-generated catch block
               e.printStackTrace();
           }
       }
   }

}