1，程序给你免费试用5次，之后不给你玩了

package javaBase.io.others;import java.io.*;import java.util.*;/* * 程序给你免费试用5次，之后不给你玩了 */public class BetaPrograme {	public static void main(String[] args) throws IOException {		File file = new File("sys.properties");//用File类		if(!file.exists())			file.createNewFile();//文件不存在就创建一个		InputStream in = new FileInputStream(file);//读取流		Properties prop = new Properties();		prop.load(in);		int count = 0;//试用次数		String value = prop.getProperty("times");		if(value!=null){			count = Integer.parseInt(value);			if(count>=5){				System.out.println("您好，您的试用次数已到，请付费！");				return;			}		}				count++;		prop.setProperty("times", count+"");		//写入文件中		OutputStream out = new FileOutputStream(file);		prop.store(out, "");		out.close();		in.close();			}}

2，将几个文本文件合成一个文件

package javaBase.io;import java.io.*;import java.util.Enumeration;import java.util.Vector;//（ArrayList非线程安全）/* * 将3个文本文件合成一个文本文件 */public class MergeText {	public static void main(String[] args) throws IOException {		Vector
    
      v = new Vector
     
      ();		v.add(new FileInputStream("1.txt"));		v.add(new FileInputStream("2.txt"));		v.add(new FileInputStream("3.txt"));		Enumeration
      
        en = v.elements();		SequenceInputStream sin = new SequenceInputStream(en);//合并流		FileOutputStream out = new FileOutputStream("4.txt");		byte[] buff = new byte[1024];		int len = 0;		while((len = sin.read(buff))!=-1){			out.write(buff,0,len);		}		out.close();		sin.close();	}}
      
     
    

3，文件分割及合并

package javaBase.io;import java.io.*;import java.util.ArrayList;import java.util.Enumeration;import java.util.Iterator;/* * 分割文件（媒体文件）然后还原 */public class SplitFile {	public static void main(String[] args) throws IOException {		split();		merge();	}	/*	 * 分割文件，最大为1M	 */	public static void split() throws IOException{		FileInputStream in = new FileInputStream("man.mp3");		FileOutputStream out = null;		byte[] buff = new byte[1024*1024];//1M  每读取1M写入文件		int len = 0;		int count = 1;		while((len = in.read(buff))!=-1){			out = new FileOutputStream("man"+(count++)+".part");			out.write(buff,0,len);//仅写入有效数据			out.close();		}		in.close();		}	/*	 * 合并文件	 */	public static void merge() throws IOException{		ArrayList
    
      list = new ArrayList
     
      ();		for(int i=1;i<=4;i++){//总共有4个文件			list.add(new FileInputStream("man"+i+".part"));		}		//vector可以直接调用elements（）方法变成enumeration；		//ArrayList用迭代器：		final Iterator
      
        it = list.iterator();//匿名内部类要使用，所以用final		Enumeration
       
         en = new Enumeration
        
         () {						@Override			public FileInputStream nextElement() {				return it.next();			}						@Override			public boolean hasMoreElements() {				return it.hasNext();			}		};		//合并流		SequenceInputStream sin = new SequenceInputStream(en);		FileOutputStream out = new FileOutputStream("man_merge.mp3");		byte[] buff = new byte[1024*1024];//这里只有1M，若是太大的话会内存溢出，可以用循环每100M新建一个输出流		int len = 0;		while((len = sin.read(buff))!=-1){			out.write(buff,0,len);		}		out.close();		sin.close();	}}