Java ObjectInputStream readUnsignedByte()用法及代碼示例

ObjectInputStream類readUnsignedByte()方法

• readUnsignedByte() 方法可在java.io包。
• readUnsignedByte() 方法用於從 ObjectInputStream 讀取一個無符號字節的數據。
• readUnsignedByte() 方法是一個非靜態方法，它隻能通過類對象訪問，如果我們嘗試使用類名訪問方法，那麽我們將得到一個錯誤。
• readUnsignedByte() 方法可能在讀取無符號字節時拋出異常。
  • IOException:在執行時遇到任何輸入/輸出錯誤時可能會拋出此異常。
  • EOF異常:當這個流到達它的末尾時，這個異常可能會拋出。

用法:

    public int readUnsignedByte();

參數：

• 它不接受任何參數。

返回值：

該方法的返回類型是int，它返回讀取的無符號字節。

例：

// Java program to demonstrate the example 
// of int readUnsignedByte() method of 
// ObjectInputStream

import java.io.*;
public class ReadUnsignedByteOfOIS {
 public static void main(String[] args) throws Exception {
  // Instantiates ObjectOutputStream , ObjectInputStream 
  // FileInputStream and FileOutputStream

  FileOutputStream file_out_stm = new FileOutputStream("D:\\includehelp.txt");
  ObjectOutputStream obj_out_stm = new ObjectOutputStream(file_out_stm);
  FileInputStream file_in_stm = new FileInputStream("D:\\includehelp.txt");
  ObjectInputStream obj_in_stm = new ObjectInputStream(file_in_stm);


  // By using writeByte() method is to write
  // byte to the obj_out_stm stream
  obj_out_stm.writeByte(-124);
  obj_out_stm.writeByte(131);
  obj_out_stm.writeByte(-182);
  obj_out_stm.writeByte(154);

  obj_out_stm.flush();

  while (obj_in_stm.available() > 0) {
   // By using readUnsingedByte() method is to read
   // unsigned byte from the obj_in_stm and returned
   // as an integer
   int val = (int) obj_in_stm.readUnsignedByte();
   System.out.println("obj_in_stm.readUnsignedByte():" + val);
  }

  // By using close() method is to 
  // close all the streams 
  file_in_stm.close();
  file_out_stm.close();
  obj_in_stm.close();
  obj_out_stm.close();
 }
}

輸出

obj_in_stm.readUnsignedByte():132
obj_in_stm.readUnsignedByte():131
obj_in_stm.readUnsignedByte():74
obj_in_stm.readUnsignedByte():154