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Java ObjectInputStream readObject()用法及代碼示例


ObjectInputStream 類的 readObject() 方法用於從 objectinputstream 中讀取一個對象。它讀取對象的類、類的簽名、靜態、非靜態字段和超類型。

用法

public final  Object  readObject() throws  IOException, ClassNotFoundException

參數

NA

返回

從流中讀取的對象。

拋出

類未找到異常

無效類異常

流損壞異常

可選數據異常

IOException

例子1

import java.io.*;
import static java.lang.System.out;

public class ObjectInputStreamreadObjectExample1 {
   public static void main(String[] args) {
      try {
          String str1 = "JavaTpoint";
          FileOutputStream outstream = new FileOutputStream("file1.txt");
          ObjectOutputStream objoutstream = new ObjectOutputStream(outstream);
          objoutstream.writeObject(new WorkClass());
          objoutstream.writeObject(str1);
          objoutstream.flush();
          ObjectInputStream objinstream = new ObjectInputStream(new FileInputStream("file1.txt"));
          WorkClass  obj = (WorkClass) objinstream.readObject();
          System.out.println("String in Serializable Class  :" + obj.str);
          System.out.println("String in MainClass : " +str1);
      } catch (Exception ex) {
         ex.printStackTrace();
      }
   }

   static class WorkClass implements Serializable {
      String str = "Welcome to javaTpoint";
      private String readObject(ObjectInputStream objin) 
         throws IOException, ClassNotFoundException {
         ObjectInputStream.GetField g = objin.readFields();
         return (String) g.get("str", null);
      }
   }
}

輸出：

String in Serializable Class  :Welcome to javaTpoint
String in MainClass : JavaTpoint

例子2

package ObjectInputStream;

import java.io.*;
import java.io.ObjectInputStream;

public class ObjectInputStreamreadObjectExample2   {
   public static void main(String[] args) {
      try {
          FileOutputStream outstream = new FileOutputStream("file1.txt");
          ObjectOutputStream objoutstream = new ObjectOutputStream(outstream);
          FileInputStream instream = new FileInputStream("file2.txt");
          ObjectInputStream objinstream = new ObjectInputStream(instream);
          String str=objinstream.toString();
          objoutstream.writeObject(new WorkClass());
          objoutstream.writeObject(str);
          objoutstream.flush();
         ObjectInputStream objinputstram = new ObjectInputStream(new FileInputStream("file1.txt"));
         //read the object from object input stream and cast it to String type.
         System.out.println("" + (String) objinstream.readObject());
          //read the object from object input stream and cast it to workclass typr.
         WorkClass obj1 = (WorkClass) objinputstram.readObject();
         System.out.println("string  in Work class :" + obj1.str1);
      } catch (Exception ex) {
         ex.printStackTrace();
      }
   }
   static class WorkClass implements Serializable {
      String str1 = "javaTpoint";
      private void readObject(ObjectInputStream objin)
         throws IOException, ClassNotFoundException {
         objin.defaultReadObject();
      }
   }
}

輸出：

[email protected]
string  in Work class :javaTpoint




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注：本文由純淨天空篩選整理自 Java ObjectInputStream readObject() Method。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。