java复制文件的4种方式及拷贝文件到另一个目录下的实例代码

private static void copyFileUsingFileStreams(File source, File dest) 
    throws IOException {   
  InputStream input = null;   
  OutputStream output = null;   
  try { 
      input = new FileInputStream(source); 
      output = new FileOutputStream(dest);     
      byte[] buf = new byte[1024];     
      int bytesRead;     
      while ((bytesRead = input.read(buf)) > 0) { 
        output.write(buf, 0, bytesRead); 
      } 
  } finally { 
    input.close(); 
    output.close(); 
  } 
} 

private static void copyFileUsingFileChannels(File source, File dest) throws IOException {   
    FileChannel inputChannel = null;   
    FileChannel outputChannel = null;   
  try { 
    inputChannel = new FileInputStream(source).getChannel(); 
    outputChannel = new FileOutputStream(dest).getChannel(); 
    outputChannel.transferFrom(inputChannel, 0, inputChannel.size()); 
  } finally { 
    inputChannel.close(); 
    outputChannel.close(); 
  } 
} 

private static void copyFileUsingApacheCommonsIO(File source, File dest) 
    throws IOException { 
  FileUtils.copyFile(source, dest); 
} 

private static void copyFileUsingJava7Files(File source, File dest) 
    throws IOException {   
    Files.copy(source.toPath(), dest.toPath()); 
}

package com.util;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
public class TestHtml {
/** 
* 复制单个文件 
* @param oldPath String 原文件路径 如：c:/fqf.txt 
* @param newPath String 复制后路径 如：f:/fqf.txt 
* @return boolean 
*/ 
public void copyFile(String oldPath, String newPath) { 
try { 
int bytesum = 0; 
int byteread = 0; 
File oldfile = new File(oldPath); 
if (oldfile.exists()) { //文件存在时 
InputStream inStream = new FileInputStream(oldPath); //读入原文件 
FileOutputStream fs = new FileOutputStream(newPath); 
byte[] buffer = new byte[1444]; 
int length; 
while ( (byteread = inStream.read(buffer)) != -1) { 
bytesum += byteread; //字节数 文件大小 
System.out.println(bytesum); 
fs.write(buffer, 0, byteread); 
} 
inStream.close(); 
} 
} 
catch (Exception e) { 
System.out.println("复制单个文件操作出错"); 
e.printStackTrace();
}
}
/** 
* 复制整个文件夹内容 
* @param oldPath String 原文件路径 如：c:/fqf 
* @param newPath String 复制后路径 如：f:/fqf/ff 
* @return boolean 
*/ 
public void copyFolder(String oldPath, String newPath) {
try { 
(new File(newPath)).mkdirs(); //如果文件夹不存在 则建立新文件夹 
File a=new File(oldPath); 
String[] file=a.list(); 
File temp=null; 
for (int i = 0; i < file.length; i++) { 
if(oldPath.endsWith(File.separator)){ 
temp=new File(oldPath+file[i]); 
} 
else{ 
temp=new File(oldPath+File.separator+file[i]); 
}
if(temp.isFile()){ 
FileInputStream input = new FileInputStream(temp); 
FileOutputStream output = new FileOutputStream(newPath + "/" + 
(temp.getName()).toString()); 
byte[] b = new byte[1024 * 5]; 
int len; 
while ( (len = input.read(b)) != -1) { 
output.write(b, 0, len); 
} 
output.flush(); 
output.close(); 
input.close(); 
} 
if(temp.isDirectory()){//如果是子文件夹 
copyFolder(oldPath+"/"+file[i],newPath+"/"+file[i]); 
} 
} 
} 
catch (Exception e) { 
System.out.println("复制整个文件夹内容操作出错"); 
e.printStackTrace();
}
}
public static void main(String[] args)throws Exception {
// //这是你的源文件，本身是存在的
// File beforefile = new File("C:/Users/Administrator/Desktop/Untitled-2.html");
//
// //这是你要保存之后的文件，是自定义的，本身不存在
// File afterfile = new File("C:/Users/Administrator/Desktop/jiekou0/Untitled-2.html");
//
// //定义文件输入流，用来读取beforefile文件
// FileInputStream fis = new FileInputStream(beforefile);
//
// //定义文件输出流，用来把信息写入afterfile文件中
// FileOutputStream fos = new FileOutputStream(afterfile);
//
// //文件缓存区
// byte[] b = new byte[1024];
// //将文件流信息读取文件缓存区，如果读取结果不为-1就代表文件没有读取完毕，反之已经读取完毕
// while(fis.read(b)!=-1){
// //将缓存区中的内容写到afterfile文件中
// fos.write(b);
// fos.flush();
// }
String oldPath="C:/Users/Administrator/Desktop/Untitled-2.html";
String newPath="C:/Users/Administrator/Desktop/jiekou0/Untitled-2.html";
TestHtml t=new TestHtml();
t.copyFile(oldPath, newPath);
}
}