filefilterstreamdemo.java

JAVA编程思想源代码 值得一下 很难找的

package chapter10;

import java.io.File;
import java.io.FilenameFilter;
import java.io.FileFilter;
import java.io.IOException;

class Filter1 implements FilenameFilter {
	String extent;

	Filter1(String extent) {
		this.extent = extent;
	}

	public boolean accept(File dir, String name) {
		int index = name.lastIndexOf("."); //文件的扩展名匹配
		if (index == -1) {
			return false;
		} else if (index == name.length() - 1) {
			return false;
		} else {
			return this.extent.equals(name.substring(index + 1));
		}
	}
}

class Filter2 implements FileFilter {
	String extent;

	Filter2(String extent) {
		this.extent = extent;
	}

	public boolean accept(File f) {
		if (f.isDirectory()) {
			return false;
		}
		String name = f.getName();
		int index = name.lastIndexOf(".");
		if (index == -1) {
			return false;
		} else if (index == name.length() - 1) {
			return false;
		} else {
			return this.extent.equals(name.substring(index + 1));
		}
	}
}

public class FileFilterStreamDemo {
	public static void main(String[] args) {
		File f = new File("C://");
		File f1 = new File("C://test.txt");
		File f2 = new File("C://test.htm");
		File f3 = new File("C://testdir.txt");
		Filter1 filter1 = new Filter1("txt");
		Filter2 filter2 = new Filter2("txt");
		try {
			if (!f1.exists()) {
				f1.createNewFile(); //指定目录下没有该文件则创建文件
			}
			if (!f2.exists()) {
				f2.createNewFile(); //指定目录下没有该文件则创建文件
			}
			if (!f3.exists()) {
				f3.mkdir(); //指定目录下没有该子目录则创建子目录
			}
		} catch (IOException e) {
			e.printStackTrace();
		}
		boolean b1 = filter1.accept(f, "test.txt");
		boolean b2 = filter1.accept(f, "test.htm");
		boolean b3 = filter1.accept(f, "testdir.txt");
		System.out.println(f1.getName() + "扩展名是否为txt:" + String.valueOf(b1));
		System.out.println(f2.getName() + "扩展名是否为txt:" + String.valueOf(b2));
		System.out.println(f3.getName() + "扩展名是否为txt:" + String.valueOf(b3));
		boolean bb1 = filter2.accept(f1);
		boolean bb2 = filter2.accept(f2);
		boolean bb3 = filter2.accept(f3);
		System.out.println(f1.getName() + "扩展名是否为txt而且是文件:"
				+ String.valueOf(bb1));
		System.out.println(f2.getName() + "扩展名是否为txt而且是文件:"
				+ String.valueOf(bb2));
		System.out.println(f3.getName() + "扩展名是否为txt而且是文件:"
				+ String.valueOf(bb3));
	}
}