grandfileaccumulator.java

java开发的 图片比较程序

package filelogic.analyzers;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.Iterator;
import java.util.TreeMap;
import java.util.Vector;
import java.util.zip.CRC32;
import java.util.zip.CheckedInputStream;

public final class GrandFileAccumulator {

	private TreeMap<String, Vector<File>> completeCRCAndFileList;

	private Vector<File> files;

	public GrandFileAccumulator(String folderpath) throws IOException {
		File dir = new File(folderpath);
		files = new Vector<File>();

		if (folderpath == null) {
			throw new NullPointerException(
					"You cannot anylize a null directory");
		} else if (dir.exists() == false || dir.isDirectory() == false) {
			throw new IOException(
					"You must specify a real directory to analyze");
		} else {

			completeCRCAndFileList = new TreeMap<String, Vector<File>>();

			// Add each file and its hash code into the treemap.
			RecursiveDirectoryParse(folderpath);
		}

		// Add each file and its hash to the tree.
		for (File current : files) {

			CheckedInputStream ci = new CheckedInputStream(new FileInputStream(
					current), new CRC32());

			// Hash the whole file, or just 1MB.
			byte[] buffer = new byte[(int) Math.min(current.length(), Math.pow(
					2, 20))];

			ci.read(buffer);

			String key = Long.toString(ci.getChecksum().getValue());

			if (completeCRCAndFileList.containsKey(key)) {
				completeCRCAndFileList.get(key).add(current);
			} else {
				completeCRCAndFileList.put(key, new Vector<File>());
				(completeCRCAndFileList.get(key)).add(current);
			}

		}
	}

	private void RecursiveDirectoryParse(String directory) {
		Vector<File> folders = new Vector<File>();
		File dir = new File(directory);

		File[] files = dir.listFiles();

		// Seperate into files...
		for (int k = 0; k < files.length; k++) {
			if (files[k].isDirectory())
				folders.add(files[k]);
			else {
				this.files.add(files[k]);
			}
		}

		for (Iterator k = folders.iterator(); k.hasNext();) {
			RecursiveDirectoryParse(((File) k.next()).getPath());
		}
	}

	public TreeMap<String, Vector<File>> getFilesAndHashes() {
		return completeCRCAndFileList;
	}
}