OutputStream 轉 InputStream 

Case 1  toByteArray

ByteArrayOutputStream out = new ByteArrayOutputStream();

new ByteArrayInputStream(out.toByteArray())

Case2 從Output字節讀取Input

          ByteArrayOutputStream out = new ByteArrayOutputStream();
          byte[] bs = new byte[] { 1, 2, 3, 4, 5 }; 
          out.write(bs);
       
          ByteArrayInputStream in = new ByteArrayInputStream(out.toByteArray())
          byte[] bs = new byte[1024];  
          int len = in.read(bs);  
          for (int i = 0; i < len; i++) {  
            System.out.println(bs[i]);  
          }  

InputStream 轉OutputStream

PipedInputStream in = new PipedInputStream();

PipedOUtputStream out = new PipedOutputStream(in);

OutputStream outputStream = null

OutputStream接收數據前，需要new出空間來，否則會報null。

OutputStream outputStream = new ByteArrayOutputStream();