ObjectInputStream类readFields()方法
- readFields() 方法可在
java.io
包。 - readFields() 方法用于从此 ObjectInputStream 读取永久字段,使它们准备好按名称访问。
- readFields() 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。
-
readFields() 方法可能会在读取字段时抛出异常。
- IOException:在执行时遇到任何输入/输出错误时可能会抛出此异常。
- 类未找到异常: 当 Class 序列化对象不存在时,可能会抛出此异常。
- 非活动异常:当流未激活以读取对象时,可能会抛出此异常。
用法:
public ObjectInputStream.GetField readFields();
参数:
- 它不接受任何参数。
返回值:
该方法的返回类型是ObjectInputStream.GetField
,它返回表示未序列化对象的永久字段的 GetField 对象。
例:
// Java program to demonstrate the example
// of ObjectInputStream.GetField readFields()
// method of ObjectInputStream
import java.io.*;
public class ReadFieldsOfOIS {
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.writeObject(new ReadFields());
obj_out_stm.flush();
// By using readObject() method is to read
// object and display fields
ReadFields rf = (ReadFields) obj_in_stm.readObject();
System.out.println("obj_in_stm.readObject():" + rf.str);
}
static class ReadFields implements Serializable {
String str = "Java Programming";
private String readObject(ObjectInputStream ois)
throws IOException, ClassNotFoundException {
// Invokes readFields()
ObjectInputStream.GetField get_f = ois.readFields();
// Return fields
return (String) get_f.get("str", null);
}
}
}
输出
obj_in_stm.readObject():Java Programming
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注:本文由纯净天空筛选整理自Preeti Jain大神的英文原创作品 Java ObjectInputStream readFields() Method with Example。非经特殊声明,原始代码版权归原作者所有,本译文未经允许或授权,请勿转载或复制。