Java复制一个目录下所有的文件夹到另一个目录下

      import java.io.*;
        import java.util.*;
        private static File[] copyfoldersList = new File("C:\\Windows\\System32").listFiles();
        for (int k = 0; k < copyfoldersList.length; k++) {
            if (copyfoldersList[k].isDirectory()) {
                LinkedList<String> copysourcepath = new LinkedList<String>(
                        Arrays.asList(copyfoldersList[k].getAbsolutePath()));
                LinkedList<String> copytargetpath = new LinkedList<String>(
                        Arrays.asList("D:"+ File.separator+ copyfoldersList[k].getAbsolutePath().substring(copyfoldersList[k].getAbsolutePath().lastIndexOf(File.separator))));
                while (copysourcepath.size() > 0) {
                    (new File(copytargetpath.peek())).mkdirs();
                    File folders = new File(copysourcepath.peek());
                    String[] file = folders.list();
                    File temp = null;
                    for (int i = 0; i < file.length; i++) {
                        if (copysourcepath.peek().endsWith(File.separator))
                            temp = new File(copysourcepath.peek(), file[i]);
                        else
                            temp = new File(copysourcepath.peek(), file[i]);
                        FileInputStream input = null;
                        FileOutputStream output = null;
                        if (temp.isFile()) {
                            try {
                                input = new FileInputStream(temp);
                                output = new FileOutputStream(new File(copytargetpath.peek(), temp.getName().toString()));
                                long filelength=input.length();
                                long buffsize=filelength<10485760L?filelength:10485760L;
                                byte[] b = new byte[buffsize];
                                int len;
                                while ((len = input.read(b)) != -1)
                                    output.write(b, 0, len);
                                output.flush();
                            } catch (IOException e) {
                                System.err.println("复制单个文件操作出错");
                            } finally {
                                try {
                                    output.close();
                                    input.close();
                                } catch (IOException e) {
                                }
                            }
                        } else if (temp.isDirectory()) {
                            for (File f : temp.listFiles()) {
                                if (f.isDirectory()) {
                                    copysourcepath.add(f.getPath());
                                    copytargetpath.add(copytargetpath.peek()
                                            + File.separator + f.getName());
                                } else if (f.isFile()) {
                                    new File(copytargetpath.peek()+ File.separator+ temp.getName()).mkdirs();
                                    FileInputStream input2 = null;
                                    FileOutputStream output2 = null;
                                    try {
                                        input2 = new FileInputStream(f);
                                        output2 = new FileOutputStream(copytargetpath.peek()+ File.separator+ temp.getName()+ File.separator+ f.getName());
                                        long filelength=input2.length();
                                        long buffsize=filelength<10485760L?filelength:10485760L;
                                        byte[] b = new byte[buffsize];
                                        int len;
                                        while ((len = input2.read(b)) != -1)
                                            output2.write(b, 0, len);
                                        output2.flush();
                                    } catch (IOException e) {
                                        System.err.println("复制单个文件操作出错");
                                    } finally {
                                        try {
                                            output2.close();
                                            input2.close();
                                        } catch (IOException e) {
                                        }
                                    }
                                }
                            }
                        }
                    }
                    copysourcepath.removeFirst();
                    copytargetpath.removeFirst();
                }
            }
        }