文件选择器

经常我老婆让我帮她从她的手机导出图片,为了避免下次再打搅我玩游戏,索性动手写了一段程序.以下程序有重复造轮子之嫌(这个需求完全可以使用Apache Commons IO来处理),但自己动手玩一下,也能从中体会良多.

package com.app.common.util.file.selector;

import java.io.File;
import java.io.FileFilter;
import java.util.*;

/**
 * 此过滤器用来过滤大于最后修改时间之后的文件
 * @author Administrator
 *
 */
public class AfterLastUpdateFileFilter implements FileFilter {

	private Date lastUpdateTime;

	public AfterLastUpdateFileFilter(Date lastUpdateTime) {

		this.lastUpdateTime = lastUpdateTime;
	}

	@Override
	public boolean accept(File file) {
		Date fileDate = new Date(file.lastModified());
		return fileDate.after(lastUpdateTime);
	}

}

package com.app.common.util.file.selector;

import java.io.*;
import java.util.*;

/**
 * 此过滤器属于组合过滤器,仅当两个过滤器验证通过,才会选中文件
 * @author Administrator
 *
 */
public class CompositeFileFilter implements FileFilter {

	private List<FileFilter> filters;

	public CompositeFileFilter(List<FileFilter> filters) {
		this.filters = filters;
	}

	@Override
	public boolean accept(File file) {
		for (FileFilter filter : filters) {
			if (filter.accept(file) == false) {
				return false;
			}
		}
		return true;
	}
}

package com.app.common.util.file.selector;

import java.io.File;
import java.io.FileFilter;

/**
 * 文件扩展名过滤器
 * @author Administrator
 *
 */
public class FileExtensionFilter implements FileFilter {

	private String extension;

	public FileExtensionFilter(String extension) {
		this.extension = extension;
	}

	@Override
	public boolean accept(File file) {
		if(file.isDirectory()){
			return false;
		}
		return file.getName().toLowerCase().endsWith(extension.toLowerCase());
	}

}

package com.app.common.util.file.selector;

import java.io.*;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.*;

import org.apache.commons.io.IOUtils;

/**
 * 文件选择测试类
 * @author Administrator
 *
 */
public class FileSelector {

	public void copyFiles(File inputDir, CompositeFileFilter fileFilter,File outDir) {
		File[] files = null;
		InputStream in = null;
		OutputStream output = null;
		if (inputDir != null && inputDir.exists() && inputDir.isDirectory()
				&& inputDir.canRead()) {
			files = inputDir.listFiles(fileFilter);
			System.out.println("select files length: " + files.length);
			for (File file : files) {
				try {
					in = new FileInputStream(file);
					System.out.println("handle: " + file.getName());
					output = new FileOutputStream(new File(outDir,
							file.getName()));
					IOUtils.copy(in, output);
				} catch (IOException e) {
					e.printStackTrace();
				} finally {
					if (null != output) {
						try {
							output.close();
						} catch (IOException e) {
							e.printStackTrace();
						}
						output = null;
					}
					if (null != in) {
						try {
							in.close();
						} catch (IOException e) {
							e.printStackTrace();
						}
						in = null;
					}
				}

			}
		}
	}

	public static void main(String[] args) throws ParseException {
		File inputDir = new File("f:/pic");
		File outDir = new File("f:/test/");
		FileSelector selector = new FileSelector();
		Date lastUpdateTime = new Date();
		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
		lastUpdateTime = sdf.parse("2012-10-28 23:59:59");
		List<FileFilter> filters = new ArrayList<FileFilter>();
		filters.add(new AfterLastUpdateFileFilter(lastUpdateTime));
		filters.add(new FileExtensionFilter(".jpg"));
		CompositeFileFilter compositeFileFilter = new CompositeFileFilter(
				filters);
		selector.copyFiles(inputDir, compositeFileFilter, outDir);
		System.out.println("finished...");
	}
}

当然还可以实现其它的过滤器,不过说真的,Apache Commons IO里的过滤器已经够强大了,完全可以用它的.除此之外,Apache Commons IO里还有很多比较器,完全可以实现你的排序要求.