SequenceInputStream（顺序输入流）学习

转 http://imain.iteye.com/blog/263741
SequenceInputStream类允许连接多个InputStream流。SequenceInputStream的构造不同于任何其他的InputStream。SequenceInputStream构造函数要么使用一对InputStream，要么用InputStream的一个Enumeration，显示如下：
SequenceInputStream(InputStream first, InputStream second)
SequenceInputStream(Enumeration streamEnum)
操作上来说，该类满足读取完第一个InputStream后转去读取第二个流的读取要求。使用Enumeration的情况下，它将继续读取所有InputStream流直到最后一个被读完。

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.InputStream;
import java.util.Enumeration;
import java.util.Vector;

public class InputStreamEnumerator implements Enumeration<InputStream> {
	private Enumeration<String> files;

	public InputStreamEnumerator(Vector<String> files){
		this.files = files.elements();
	}

	public boolean hasMoreElements() {
		return files.hasMoreElements();
	}

	public InputStream nextElement() {
		try {
			return new FileInputStream(System.getProperty("user.dir")+"/"+files.nextElement().toString());
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		}
		return null;
	}

}

import java.io.InputStream;
import java.io.SequenceInputStream;
import java.util.Vector;

public class SequenceInputStreamDemo {
	public static void main(String[] args) throws Exception {
		int c;
		Vector<String> files = new Vector<String>();
		files.addElement("file1.txt");
		files.addElement("file2.txt");
		InputStreamEnumerator e = new InputStreamEnumerator(files);
		InputStream input = new SequenceInputStream(e);
		while((c=input.read())!=-1){
			System.out.print((char)c); 
		}
		input.close();

	}
}