如何理解流中的数据流、对象流和打印流

这篇文章给大家介绍如何理解流中的数据流、对象流和打印流，内容非常详细，感兴趣的小伙伴们可以参考借鉴，希望对大家能有所帮助。

数据流:DataOutputStream

public class TestDataStream {     public void writeData()     {         double[] arrays = new double[1000];         Arrays.fill(arrays, Math.PI);                  String fileName = "F:/java/test2.txt";         FileOutputStream out;         DataOutputStream dos = null;         try         {             out = new FileOutputStream(fileName);             dos = new DataOutputStream(out);             for (int i = 0; i < arrays.length; i++)             {                 dos.writeDouble(arrays[i]);             } //            dos.write(123); //            dos.writeBoolean(true); //            dos.writeChar('Z'); //            dos.writeDouble(Math.PI);             dos.flush();         }         catch (FileNotFoundException e)         {             e.printStackTrace();         }         catch (IOException e)         {             e.printStackTrace();         }         finally         {             if (dos != null)             {                 try                 {                     dos.close();                 }                 catch (IOException e)                 {                     e.printStackTrace();                 }             }         }     }          public static void main(String[] args)     {         TestDataStream tds = new TestDataStream();         tds.writeData();          }      }

数据流:DataInputStream

public class TestDataInputStream {     public static void main(String[] args)     {         String fileName = "F:/java/test2.txt";         FileInputStream in = null;         DataInputStream dis = null;         try         {             in = new FileInputStream(fileName);             dis = new DataInputStream(in);             for (int i = 0; i < 1000; i++)             {                 System.out.println(dis.readDouble() + "i: " + i);             } //            System.out.println(dis.read()); //            System.out.println(dis.readBoolean()); //            System.out.println(dis.readChar()); //            System.out.println(dis.readDouble());         }         catch (FileNotFoundException e)         {             e.printStackTrace();         }         catch (IOException e)         {             e.printStackTrace();         }         finally         {             if (dis != null)             {                 try                 {                     dis.close();                 }                 catch (IOException e)                 {                     e.printStackTrace();                 }             }         }     } }

对象流：ObjectOutputStream（unserializable）、ObjectInputStream（serializable）

public class TestSerializable {     public static void main(String[] args)     {         TestSerializable ts = new TestSerializable();         ts.serializable();         ts.unserializable();     }     public void serializable()//序列化，写入     {         String filename = "F:/java/stu.txt";         Student s1 = new Student("haoyouduo",1987);                  FileOutputStream fis =null;         ObjectOutputStream ois = null;         try         {             fis = new FileOutputStream(filename);             ois = new ObjectOutputStream(fis);             ois.writeObject(s1);             ois.flush();         }         catch (FileNotFoundException e)         {             e.printStackTrace();         }         catch (IOException e)         {             e.printStackTrace();         }         finally         {             if(null != ois)             {                 try                 {                     ois.close();                 }                 catch (IOException e)                 {                     e.printStackTrace();                 }             }         }              }     public void unserializable()//反序列化，读取     {         String filename = "F:/java/stu.txt";         FileInputStream fis = null;         ObjectInputStream ois = null;         try         {             fis = new FileInputStream(filename);             ois = new ObjectInputStream(fis);             Student s = (Student)ois.readObject();             System.out.println(s);                      }         catch (FileNotFoundException e)         {             e.printStackTrace();         }         catch (IOException e)         {             e.printStackTrace();         }         catch (ClassNotFoundException e)         {             e.printStackTrace();         }         finally         {             if(ois != null)             {                 try                 {                     ois.close();                 }                 catch (IOException e)                 {                     e.printStackTrace();                 }             }         }              } }  class Student implements Serializable//对象类必须实现可序列化的 {     String name;     int age;     public Student(String name,int age)     {         this.name = name;         this.age = age;     }     @Override     public String toString()     {         return "Student [name=" + name + ", age=" + age + "]";     }       }

打印流:PrintStream

public class Test {     public static void main(String[] args)     {         boolean flag = 2 > 1;         if (flag)         {             System.out.println("sss");         }         else         {             System.out.println("aaa");         }                  System.out.println("使用printStream之前");          /**          * 上面部分的内容将打印在控制台里          * 下面部分的内容不会打印在控制台里，而是文件里          */                  String filename = "f:/java/log.txt";         FileOutputStream fos;         PrintStream ps = null;         try         {             fos = new FileOutputStream(filename);             ps = new PrintStream(fos);             System.setOut(ps);             System.out.println("这将打印在文件里");             System.out.println("使用printStream之后");         }         catch (FileNotFoundException e)         {             e.printStackTrace();         }         finally         {             if (ps != null)             {                 ps.close();             }         }     } }

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