基础篇——序列化和文件的输入输出

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() != null
reader.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();