Java ObjectInputStream readUnsignedByte()用法及代码示例

ObjectInputStream类readUnsignedByte()方法

• readUnsignedByte() 方法可在java.io包。
• readUnsignedByte() 方法用于从 ObjectInputStream 读取一个无符号字节的数据。
• readUnsignedByte() 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。
• readUnsignedByte() 方法可能在读取无符号字节时抛出异常。
  • IOException:在执行时遇到任何输入/输出错误时可能会抛出此异常。
  • EOF异常:当这个流到达它的末尾时，这个异常可能会抛出。

用法:

    public int readUnsignedByte();

参数：

• 它不接受任何参数。

返回值：

该方法的返回类型是int，它返回读取的无符号字节。

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();
 }
}

输出

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