如何从Java中的文件读取对象

àì夳堔傛蜴生んèń 2023-02-15 05:28 102阅读 0赞

在前面的示例中，您将学习[如何将对象写入文件][Link 1] 。 在此示例中，您将学习如何从保存的文件中读取对象或如何反序列化序列化的文件。

反序列化的过程与序列化非常相似，您需要使用`ObjectInputStream`读取文件的内容并将其转换回Java对象。

FileInputStream fin = new FileInputStream("c:\\temp\\address.ser");
    ObjectInputStream ois = new ObjectInputStream(fin);
    address = (Address) ois.readObject();

## 1.从文件读取对象 ##

此类将读取序列化文件`c:\\temp\\address.ser` （在[本示例中][Link 1]创建），然后将其转换回“ Address”对象并打印出保存的值。

ReadObject.java

package com.mkyong.io;
    
    import java.io.FileInputStream;
    import java.io.IOException;
    import java.io.ObjectInputStream;
    
    public class ReadObject {
    
    	public static void main(String args[]) {
    
    		ReadObject obj = new ReadObject();
    
    		Address address = obj.deserialzeAddress("c:\\temp\\address.ser");
    
    		System.out.println(address);
    
    	}
    
    	public Address deserialzeAddress(String filename) {
    
    		Address address = null;
    
    		FileInputStream fin = null;
    		ObjectInputStream ois = null;
    
    		try {
    
    			fin = new FileInputStream(filename);
    			ois = new ObjectInputStream(fin);
    			address = (Address) ois.readObject();
    
    		} catch (Exception ex) {
    			ex.printStackTrace();
    		} finally {
    
    			if (fin != null) {
    				try {
    					fin.close();
    				} catch (IOException e) {
    					e.printStackTrace();
    				}
    			}
    
    			if (ois != null) {
    				try {
    					ois.close();
    				} catch (IOException e) {
    					e.printStackTrace();
    				}
    			}
    
    		}
    
    		return address;
    
    	}
    
    	public Address deserialzeAddressJDK7(String filename) {
    
    		Address address = null;
    
    		try (ObjectInputStream ois 
    			= new ObjectInputStream(new FileInputStream(filename))) {
    
    			address = (Address) ois.readObject();
    
    		} catch (Exception ex) {
    			ex.printStackTrace();
    		}
    
    		return address;
    
    	}
    
    }

输出量

Street : wall street Country : united state

## 参考文献 ##

1.  [ObjectOutputStream JavaDoc][]
2.  [Java对象序列化][Java]
3.  [JDK 7中的try-with-resources示例][JDK 7_try-with-resources]

标签： [文件][Link 2] [读取对象中的][Link 3] [io][] [java][] [java.io][] [对象][Link 3]

> 翻译自: [https://mkyong.com/java/how-to-read-an-object-from-file-in-java/][https_mkyong.com_java_how-to-read-an-object-from-file-in-java]

[Link 1]: http://www.mkyong.com/java/how-to-write-an-object-to-file-in-java/
[ObjectOutputStream JavaDoc]: https://docs.oracle.com/javase/7/docs/api/java/io/ObjectInputStream.html
[Java]: https://docs.oracle.com/javase/8/docs/technotes/guides/serialization/
[JDK 7_try-with-resources]: https://www.mkyong.com/java/try-with-resources-example-in-jdk-7/
[Link 2]: https://mkyong.com/tag/object-in-file/
[Link 3]: https://mkyong.com/tag/read-object/
[io]: https://mkyong.com/tag/io/
[java]: https://mkyong.com/tag/java/
[java.io]: https://mkyong.com/tag/java-io/
[https_mkyong.com_java_how-to-read-an-object-from-file-in-java]: https://mkyong.com/java/how-to-read-an-object-from-file-in-java/