Java DataOutputStream flush()用法及代码示例

DataOutputStream类flush()方法

• flush() 方法可在java.io包。
• flush() 方法用于刷新此流并强制将字节写入基本流。
• flush() 方法是一个非静态方法，它只能通过类对象访问，如果我们尝试使用类名访问方法，那么我们将得到一个错误。
• flush() 方法可能会在刷新流时抛出异常。
  IOException: 获取任何输入/输出错误时可能会抛出此异常。

用法:

    public void flush();

参数：

• 它不接受任何参数。

返回值：

该方法的返回类型是void，它什么都不返回。

例：

// Java program to demonstrate the example 
// of void flush() method of DataOutputStream

import java.io.*;

public class FlushOfDOS {
 public static void main(String[] args) throws IOException {
  InputStream is_stm = null;
  DataInputStream dis_stm = null;
  FileOutputStream fos_stm = null;
  DataOutputStream dos_stm = null;
  byte[] b_arr = {
   12,
   20,
   45,
   98,
   75,
   69,
   30,
   58,
   47,
   61,
   83,
   55
  };

  try {
   // Instantiate FileInputStream, 
   // DataInputStream, FileOutputStream
   // and DataOutputStream 

   fos_stm = new FileOutputStream("C:\\Users\\Preeti Jain\\Desktop\\programs\\includehelp.txt");
   dos_stm = new DataOutputStream(fos_stm);
   is_stm = new FileInputStream("C:\\Users\\Preeti Jain\\Desktop\\programs\\includehelp.txt");
   dis_stm = new DataInputStream(is_stm);

   // Loop to write each byte till end
   for (byte val:b_arr) {
    // By using write() method isto
    // write a byte value to the
    // DataOutputStream dos_stm
    dos_stm.write(val);
   }

   // By using flush() method isto
   // flush the stream and forces bytes
   // are written out immediately of any 
   // buffered output
   dos_stm.flush();

   // Loop To Read Available Data till end
   while (dis_stm.available() > 0) {
    // By using read() method isto read 
    // byte from dis_stm
    int in = dis_stm.read();
    System.out.println("dis_stm.read():" + in );
   }
  } catch (Exception ex) {
   System.out.println(ex.toString());
  } finally {
   // To free system resources linked
   // with these streams
   if (is_stm != null)
    is_stm.close();

   if (dis_stm != null)
    dis_stm.close();

   if (dos_stm != null)
    dos_stm.close();

   if (fos_stm != null)
    fos_stm.close();
  }
 }
}

输出

dis_stm.read():12
dis_stm.read():20
dis_stm.read():45
dis_stm.read():98
dis_stm.read():75
dis_stm.read():69
dis_stm.read():30
dis_stm.read():58
dis_stm.read():47
dis_stm.read():61
dis_stm.read():83
dis_stm.read():55