java.io.ObjectInputStream.getField.get(String name, byte val)方法實例

java.io.ObjectInputStream.getField.get(String name, byte val) 方法從持久字段獲取指定字節字段的值。

聲明

以下是java.io.ObjectInputStream.getField.get()方法聲明

public abstract byte get(String name, byte val)

參數

• name -- 該字段的名稱

• val -- 默認值使用，如果名稱不具有值

返回值

此方法返回指定字節字段的值

異常

• IOException -- 如果從基礎InputStream讀取有I / O錯誤

• IllegalArgumentException -- 如果name的類型不是可序列化的或者字段類型不正確

例子

下面的示例演示java.io.ObjectInputStream.getField.get()方法的用法。

package com.yiibai; import java.io.*; public class ObjectInputStreamDemo implements Serializable { public static void main(String[] args) { try { // create a new file with an ObjectOutputStream FileOutputStream out = new FileOutputStream("test.txt"); ObjectOutputStream oout = new ObjectOutputStream(out); // write something in the file oout.writeObject(new Example()); oout.flush(); oout.close(); // create an ObjectInputStream for the file we created before ObjectInputStream ois = new ObjectInputStream(new FileInputStream("test.txt")); // read an object from the stream and cast it to Example Example a = (Example) ois.readObject(); // print var variable of a System.out.println("" + a.var); } catch (Exception ex) { ex.printStackTrace(); } } static public class Example implements Serializable { static byte var = 5; // assign a new serialPersistentFields private static final ObjectStreamField[] serialPersistentFields = { new ObjectStreamField("var", Byte.TYPE) }; private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException { // get the field and assign it at string variable ObjectInputStream.GetField fields = in.readFields(); // check if string is defaulted, meaning if it has no value byte b = 0; var = (byte) fields.get("var", b); } private void writeObject(ObjectOutputStream out) throws IOException { // write into the ObjectStreamField array the variable var ObjectOutputStream.PutField fields = out.putFields(); fields.put("var", var); out.writeFields(); } } }

讓我們編譯和運行上面的程序，這將產生以下結果：

5