package?day7; import?java.io.DataInput; import?java.io.DataInputStream; import?java.io.DataOutputStream; import?java.io.FileInputStream; import?java.io.FileNotFoundException; import?java.io.FileOutputStream; import?java.io.IOException; import?java.util.Scanner; public?class?OpenrData?{ public?static?void?main(String[]?args)?throws?IOException?{ Scanner?sc=new?Scanner(System.in); System.out.println("請輸入要轉化的數據文件："); DataOutputStream?dos?=new?DataOutputStream(dos); DataInputStream?dis?=null; try?{ dos.writeDouble(Math.random()); dos.flush(); dis=new?DataInputStream(dis); System.out.println(dis.readBoolean()); System.out.println(dis.readDouble()); ??} catch?(Exception?e)?{ //?TODO:?handle?exception e.printStackTrace(); } finally?{ try?{ if(dis?!=?null){ ??????????????????????dis.close(); ????????????????} ????if(dos?!=?null){ ????????????????????????dos.close(); ??????????????????} }?catch?(Exception?e2)?{ //?TODO:?handle?exception ??e2.printStackTrace(); } } } } 在class往后的第五行中的dos總是顯示報錯，這是為什么，還有IO數據流到底是從哪里到哪里 我完全懵了，求大神幫幫我！