Java ObjectInputStream readInt()用法及代碼示例

ObjectInputStream類readInt()方法

• readInt() 方法可在java.io包。
• readInt() 方法用於從此 ObjectInputStream 流中讀取 4 個字節(即 32 位)的數據並返回一個整數。
• readInt() 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。
• readInt() 方法可能在讀取整數時拋出異常。
  • 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:當此流到達文件末尾時，可能會拋出此異常。

用法:

    public int readInt();

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 4 字節整數值。

例：

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

import java.io.*;

public class ReadIntOfOIS {
 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 writeInt() method is to write
  // integer to the obj_out_stm stream
  obj_out_stm.writeInt(100);
  obj_out_stm.writeInt(200);
  obj_out_stm.writeInt(300);
  obj_out_stm.writeInt(400);

  obj_out_stm.flush();

  while (obj_in_stm.available() > 0) {
   // By using readInt() method is to read
   //  integer from the obj_in_stm
   int val = (int) obj_in_stm.readInt();
   System.out.println("obj_in_stm.readInt():" + 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.readInt():100
obj_in_stm.readInt():200
obj_in_stm.readInt():300
obj_in_stm.readInt():400