基础篇——序列化和文件的输入输出

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一、对象序列化（存储）

FileOutputStream fileStream = new FileOuputStream("file.ser");

ObjectOutputStream os = new ObjectOutputStream(fileStream);

os.writeObject(one);//Help one = new Help();os.writeObject(two);

os.close();

当对象被序列化时，被该对象引用的实例变量也会被序列化，且所有被引用的对象都会被序列化。

要想类被序列化，必须实现Serializable：

public class Box implements Serializable{private int x;transient String y;Animal a = new Animale();...}

public class Animal{...}

x会被保存；y不会被序列化，transient标记的变量被跳过；a不会，因为Animal类没有实现Serializable。

二、解序列化

FileInputStream fileStream = new FileInputStream("file.ser");

ObjectInputStream is = new ObjectInputStream(fileStream);

Object one = is.readObject();Object two = is.readObject();

Help oneHelp = (Hlep)one;Help twoHelp = (Hlep)two;

is.close();

三、文件读写

File myFile = new File("MyText.txt");FileReader fileReader = new FileReader(myFile);BufferedReader reader = new BufferedReader(fileReader);while reader.readLine() != nullreader.close();

File myFile = new File("1.txt");FileWriter fileWriter = new FileWriter(myFile);BufferedWriter writer = new BufferedWriter(fileWriter);writer.write("hello");writer.close();

四、目录操作

File dir = new File("dir1");dir.mkdir();if(dir.idDirectory()){String [] dirContents = dir.list();for(int i = 0;i < dirContents.length;i++){System.out.println(dirContents[i]);}}System.out.println(dir.getAbsolutePath());dir.delete();

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