关于IO流问题关于文件复制的(初学)

注：使用了Apache commons io包(http://commons.apache.org/io/)，这种基础操作可以自己写，但是用别人类库更方便。
import java.io.File;
import java.io.IOException;import org.apache.commons.io.FileUtils;
import org.apache.commons.io.filefilter.FileFilterUtils;public class Test { public static void main(String[] args) throws IOException {
FileUtils.copyDirectory(new File("c:\\file"), new File("d:\\file"), FileFilterUtils.suffixFileFilter(".jpg"));
}
}

public static void main(String[] args) throws IOException{
File src = new File("c:\\file");//原目录
File tar = new File("d:\\file");//目标目录
tar.mkdirs();//生成目标目录
InputStream fileInput = null;
OutputStream fileOutput = null;
byte[] buffer = new byte[1024];
//遍历原目录中扩展名为jpg或html的文件
for(File f:src.listFiles(new FilenameFilter(){
public boolean accept(File dir, String name) {
return name.endsWith("jpg")||name.endsWith("html");
}})){
fileInput = new FileInputStream(f);
fileOutput = new FileOutputStream(tar.getPath()+File.separator+f.getName());
while(fileInput.read(buffer)!= -1) {
fileOutput.write(buffer);
}
}
fileInput.close();
fileOutput.close();
}

package CSDNTest;import java.io.*;
import java.net.URL;public class Download {

    private static void copyFile(File input, File output) throws IOException {
     InputStream in = input.toURL().openStream();
     try {
     OutputStream out = new FileOutputStream(output);
     try {
     copy(in, out);
     } finally {
     out.close();
     }
     } finally {
     in.close();
     }
    }    private static void copy(InputStream in, OutputStream out)
            throws IOException {
        byte[] buffer = new byte[1024];
        while (true) {
            int readCount = in.read(buffer);
            if (readCount == -1) {
                break;
            }
            out.write(buffer, 0, readCount);
        }
    }    public static void main(String[] args) {
        try {
            //URL url = new URL("http://sohu.com");
            File input = new File("D:\\a\\update.exe");
            File output = new File("D:\\a\\update1.exe");
            copyFile(input, output);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}单个复制

没有考虑file下是目录的情况，加上去就完整了

import java.io.*;
public class TestFileOutputStream {
  public static void main(String[] args) {
  int b = 0;
  FileInputStream in = null;
  FileOutputStream out = null;
  try {
    in = new FileInputStream("c:\file");
    out = new FileOutputStream("d:\file");
    while((b=in.read())!=-1){
      out.write(b);
    }
    in.close();
    out.close();
  } catch (FileNotFoundException e2) {
    System.out.println("找不到指定文件"); System.exit(-1);
  } catch (IOException e1) {
    System.out.println("文件复制错误"); System.exit(-1);
  }
  System.out.println("文件已复制");
  }
}
希望对你有用！我也是初学JAVA。

/**
* 读出1.txt中的内容，写入2.txt中
*
*/import java.io.*;public class ReadWriteFile{
public static void main(String[] args){
try{File read = new File("c:\\1.txt");
File write = new File("c:\\2.txt"); BufferedReader br = new BufferedReader(
new FileReader(read));
BufferedWriter bw = new BufferedWriter(
new FileWriter(write));
String temp = null;
temp = br.readLine();
while(temp != null){
//写文件
bw.write(temp + "\n"); //只适用Windows系统
//继续读文件
temp = br.readLine();
}bw.close();
br.close();}catch(FileNotFoundException e){ //文件未找到
System.out.println (e);
}catch(IOException e){
System.out.println (e);
}
}
} Java IO 多种方式读文件一、多种方式读文件内容。
1、按字节读取文件内容
2、按字符读取文件内容
3、按行读取文件内容
4、随机读取文件内容
http://hi.baidu.com/binky2008/blog/item/9c072744a522cd4f500ffe77.html

快成了找错误了.
还有流关闭也有问题.如果不存在jpg或html文件的话,那流就为空。会空指针...
我觉得没问题的就那个public static void main....

所以还是用类库的好，方便实用，而且能满足各种需求。我上面写的仅是其中一个方法，还有很多有用的方法。再复制文件的时候要考虑空指针、路径不存在、文件不存在、覆盖已有文件、确保流关闭、合理实用buffer等一系列问题，否则只能是实验性质的自己写着玩玩的系统。

package filecopy;import java.io.File;
import java.io.FileFilter;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.LinkedList;
public class File_copy implements FileFilter{
    private String savePlace;
    private String searchPlace;
    private String type=".jpg";
    private LinkedList<String> list;
    private ArrayList<File> fileList;
    private boolean targ;
    /**
     * @param args the command line arguments
     */
    public void searchFile(String searchPlace){
        list=new LinkedList();
        fileList=new ArrayList();
        list.offer(searchPlace);
        while(list.peek()!=null){
            File file=new File(list.pop());
            File[] files=file.listFiles(this);
            int i=0;
            for(File f;i<files.length;){f=files[i]; i++;
                if(f.isDirectory())  list.add(f.getPath());
                else fileList.add(f);
            }
        }
    }    public void copyFile(String savePlace) throws FileNotFoundException, IOException{
        byte[] buff=new byte[1024];
        for(int i=0;i<fileList.size();i++){
            FileInputStream fis=new FileInputStream(fileList.get(i));
            FileOutputStream fos=new FileOutputStream(savePlace+"\\"+fileList.get(i).getName());
            int length=fis.read(buff);
            while(length!=-1){
                fos.write(buff,0,length);
                length=fis.read(buff);
            }
            fis.close();
            fos.close();
        }
    }    public static void main(String[] args) throws FileNotFoundException, IOException {
        // TODO code application logic here
        long time=System.currentTimeMillis();
        File_copy fc=new File_copy();
        fc.searchFile("C:\\Documents and Settings\\rgbhsodiy\\桌面\\123");
        fc.copyFile("F:\\110");
        System.out.println("There is "+fc.fileList.size()+" files!");
        System.out.println("There is cost "+(System.currentTimeMillis()-time));
    }    public boolean accept(File pathname) {
        if(pathname.isDirectory())  return true;
        else if(pathname.isFile()&&pathname.getName().endsWith(type))  return true;
        else return false;
    }
}

调试易

关于IO流问题关于文件复制的(初学)

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