(20)IO流之SequenceInputStream 序列流

序列流，对多个流进行合并。

SequenceInputStream 表示其他输入流的逻辑串联。它从输入流的有序集合开始，并从第一个输入流开始读取，直到到达文件末尾，接着从第二个输入流读取，依次类推，直到到达包含的最后一个输入流的文件末尾为止。

序列流，对多个流进行合并。

SequenceInputStream 表示其他输入流的逻辑串联。它从输入流的有序集合开始，并从第一个输入流开始读取，直到到达文件末尾，接着从第二个输入流读取，依次类推，直到到达包含的最后一个输入流的文件末尾为止。

合并两个流

使用构造函数SequenceInputStream(InputStream s1, InputStream s2)

 //使用SequenceInputStream合并两个文件
     public static void merge2() throws IOException{
         //找到目标文件
         File inFile1 = new File("d:\\a.txt");
         File inFile2 = new File("d:\\b.txt");
         File outFile = new File("D:\\c.txt");
         //建立数据通道
         FileOutputStream fileOutputStream = new FileOutputStream(outFile);
         FileInputStream fileInputStream1 = new FileInputStream(inFile1);
         FileInputStream fileInputStream2 = new FileInputStream(inFile2);

         //建立序列流对象
         SequenceInputStream inputStream = new SequenceInputStream(fileInputStream1,fileInputStream2);
         byte[] buf = new byte[];
         int length = ;
         while((length = inputStream.read(buf))!=-)
         {
             fileOutputStream.write(buf, , length);
         }
         inputStream.close();
 //        fileInputStream1.close();    //查看上面inputStream.close（）的源码就可以看到，它穿起来的流一块关闭了
 //        fileInputStream2.close();
         fileOutputStream.close();
 }

合并多个文件

 //把三个文件合并成一个文件
     public static void merge3() throws IOException
     {
         //找到目标文件
         File file1 = new File("d:\\a.txt");
         File file2 = new File("d:\\b.txt");
         File file3 = new File("D:\\c.txt");
         File file4 = new File("d:\\d.txt");
         //建立对应的输入输出流对象
         FileInputStream fileInputStream1 = new FileInputStream(file1);
         FileInputStream fileInputStream2 = new FileInputStream(file2);
         FileInputStream fileInputStream3 = new FileInputStream(file3);
         FileOutputStream fileOutputStream = new FileOutputStream(file4);

         //创建序列流对象
         Vector<FileInputStream> vector = new Vector<FileInputStream>();
         vector.add(fileInputStream1);
         vector.add(fileInputStream2);
         vector.add(fileInputStream3);
         Enumeration<FileInputStream> e = vector.elements();

         SequenceInputStream inputStream = new SequenceInputStream(e);

         //读取文件的数据
         int length =;
         byte[] buf = new byte[];
         while((length = inputStream.read(buf))!=-)
         {
             fileOutputStream.write(buf, , length);
         }
         inputStream.close();
         fileOutputStream.close();
     }

下面是一个例子把一个mp3文件切割合并的过程：

 public class Demo2
 {
     public static void main(String[] args) throws IOException
     {
         cutFile();
         mergeFile();
     }

     //合并
     public static void mergeFile() throws IOException
     {
         //找到目标文件
         File dir = new File("D:\\part");
         Vector<FileInputStream> vector = new Vector<FileInputStream>();
         //通过目标文件夹找到所有的mmp3并添加到Vector中
         File[] files =  dir.listFiles();
         for (File file : files)
         {
             if(file.getName().endsWith("mp3"))
             {
                 vector.add(new FileInputStream(file));
             }
         }

         //通过vector获取迭代器对象
         Enumeration<FileInputStream> e =  vector.elements();

         SequenceInputStream inputStream = new SequenceInputStream(e);

         //建立文件的输出通道
         FileOutputStream fileOutputStream = new FileOutputStream("D:\\merge.mp3");
         //建立缓冲数组
         int length = ;
         byte[] buf = new byte[*];
         while((length = inputStream.read(buf))!=-)
         {
             fileOutputStream.write(buf, , length);
         }
     }

     //切割
     public static void cutFile() throws IOException
     {
         File file = new File("D:\\1.mp3");
         //目标文件夹
         File dir = new File("D:\\part");
         //建立数据的输入通道
         FileInputStream fileInputStream = new FileInputStream(file);
         //建立缓存数组存储
         byte[] buf = new byte[*];
         int length = ;
         for(int i =  ; (length = fileInputStream.read(buf))!=-; i ++)
         {
             FileOutputStream fileOutputStream = new FileOutputStream(new File(dir, "part"+i+".mp3"));
             fileOutputStream.write(buf, , length);
             fileOutputStream.close();
         }
         //关闭资源
         fileInputStream.close();
     }
 }