Java基础--常用IO流使用实例

读取文本文件:

 private static void ioDemo1() {
     try {
         FileReader fileReader = new FileReader("C:\\Users\\yan\\Desktop\\编码规范 (2).txt");
         int aa;
         aa = fileReader.read();
         while (aa!=-1) {//转换为char类型，否则是一堆数字
             System.out.print((char)aa);
             aa = fileReader.read();
         }
         fileReader.close();
     } catch (FileNotFoundException e) {
         e.printStackTrace();
     } catch (IOException e) {
         e.printStackTrace();
     }
 }

复制二进制文件:

 private static void ioDemo2() {
     try {
         FileInputStream fr = new FileInputStream("D:/test.xlsx");//不能使用FileReader（字符流）
         FileOutputStream fw = new FileOutputStream("D:/test1.xlsx");
         int read = fr.read();
         while (read!=-1) {
             fw.write(read);
             read=fr.read();
         }
         fw.flush();//杯子中没有饮料不代表饮料已喝完，此方法就是清空吸管中的饮料
         fw.close();
         fr.close();
     } catch (FileNotFoundException e) {
         e.printStackTrace();
     } catch (IOException e) {
         e.printStackTrace();
     }
 }

使用缓冲流复制二进制文件:

 private static void ioDemo3() {
     try {
         BufferedInputStream bis = new BufferedInputStream(new FileInputStream("D:/test.xlsx"));
         BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream("C:\\Users\\yan\\Desktop\\test.xlsx"));
         byte[] buffer = new byte[2048];
         int read = bis.read(buffer);
         while(read!=-1)
         {
             bos.write(buffer, 0, read);
             read = bis.read(buffer);
         }
         bos.flush();
         bos.close();
         bis.close();
     } catch (FileNotFoundException e) {
         e.printStackTrace();
     } catch (IOException e) {
         e.printStackTrace();
     }
 }

数据流传递数据:

     private static void ioDemo4() {
         try {

             ByteArrayOutputStream baos = new ByteArrayOutputStream();
             DataOutputStream dos = new DataOutputStream(baos);
             long src = 1234454544;
             dos.writeLong(src);

             byte[] bytes = baos.toByteArray();
             ByteArrayInputStream bais = new ByteArrayInputStream(bytes);
             DataInputStream dis = new DataInputStream(bais);
             long recieve;
             recieve = dis.readLong();

             System.out.println("recieve:" + recieve);

         } catch (IOException e) {
             e.printStackTrace();
         }
     }

PrintStream:

参考

ObjectStream：

     private static void ioDemo5() {
         ObjectOutputStream oos = null;
         ObjectInputStream ois = null;
         Student s = new Student("悟空", 007, 95.5f);
         Student s1 = null;

         try {
             FileOutputStream fos = new FileOutputStream("C:\\Users\\yan\\Desktop/ccc.txt");
             oos = new ObjectOutputStream(fos);
             oos.writeObject(s);

             ois = new ObjectInputStream(new FileInputStream("C:\\Users\\yan\\Desktop/ccc.txt"));
             s1 = (Student) ois.readObject();

             System.out.println("姓名：" + s1.getName());
             System.out.println("学号：" + s1.getId());
             System.out.println("成绩：" + s1.getScore());
             fos.close();
         } catch (Exception e) {
             e.printStackTrace();
         } finally {
             try {
                 oos.close();
                 ois.close();
                 System.exit(-1);
             } catch (Exception e) {
                 System.exit(-1);
             }
         }
     }
 //实现Serializable的作用是可以将对象保存在文件中用于传输
 class Student implements Serializable {
     private static final long serialVersionUID = -111977186014986048L;
     private String name;
     private int id;
     private transient float score;//transient意思是转瞬即逝，起的作用是反序列化

     public Student(String name, int id, float score) {
         super();
         this.name = name;
         this.id = id;
         this.score = score;
     }

     public String getName() {
         return name;
     }

     public void setName(String name) {
         this.name = name;
     }

     public int getId() {
         return id;
     }

     public void setId(int id) {
         this.id = id;
     }

     public float getScore() {
         return score;
     }

     public void setScore(float score) {
         this.score = score;
     }
 }