Java DataOutputStream writeBytes()用法及代码示例

DataOutputStream类writeBytes()方法

• writeBytes() 方法可在java.io包。
• writeBytes() 方法用于将给定的字符串作为字节序列写入基本输出流。
• writeBytes() 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。
• writeBytes() 方法可能在写入字符串时抛出异常。
  IOException:在获取任何输入/输出错误时可能会抛出此异常。

用法:

    public final void writeBytes(String str);

参数：

• String str– 表示要写入基本数据输出流的字符串。

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 writeBytes(String str) method 
// of DataOutputStream

import java.io.*;

public class WriteBytesOfDOS {
 public static void main(String[] args) throws Exception {
  ByteArrayOutputStream baos_stm = null;
  DataOutputStream dos_stm = null;

  String str = "Java World";

  try {
   // Instantiates ByteArrayOutputStream, DataOutputStream
   baos_stm = new ByteArrayOutputStream();
   dos_stm = new DataOutputStream(baos_stm);

   // By using writeBytes() method isto write
   // value in bytes from the given str
   // to the dos_stm stream
   dos_stm.writeBytes(str);

   // By using flush() method isto
   // flush output bytes are written out
   // to the basic output stream
   dos_stm.flush();

   // Display str in bytes
   System.out.println("dos_stm.writeBytes(str):" + str);

   System.out.println();

   // By using toByArray() method isto
   // convert the stream baos_stm to byte 
   // array
   byte[] by = baos_stm.toByteArray();

   // Loop to display each byte to the
   // baos_stm data till its end

   for (byte val:by) {
    // Display corresponding byte to each of the
    // given character represented in a string
    System.out.println("dos_stm.writeByte():" + val);
   }
  } catch (Exception ex) {
   System.out.println(ex.toString());
  } finally {
   // this block is to free all necessary system 
   // resources linked with the stream
   if (baos_stm != null)
    baos_stm.close();

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

输出

dos_stm.writeBytes(str):Java World

dos_stm.writeByte():74
dos_stm.writeByte():97
dos_stm.writeByte():118
dos_stm.writeByte():97
dos_stm.writeByte():32
dos_stm.writeByte():87
dos_stm.writeByte():111
dos_stm.writeByte():114
dos_stm.writeByte():108
dos_stm.writeByte():100