笔记 第1章 流与文件(8) 序列化方法

 1.5.2 修改默认的序列化机制

Serializable 修饰类，阻止部分变量序列化的方式：

使用 static 修饰

使用 transient 关键字修饰

可序列号类读写对象签名方法：

从 Serializable拷贝即可：

一般就用到前两个方法读写，第三个是对于读空数据处理

Main.java

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import com.dyy.jdk8.test.Employee;
import java.io.*;
public class Main {
    public static  void main(String[] args) throws IOException, ClassNotFoundException {
        Main solution = new Main();
 
        Employee[] staff = new Employee[3];
 
        staff[0] = new Employee("Carl Cracker", 75000,1987, 12, 15);
        staff[1] = new Employee("Harry Hacker", 50000, 1989, 10, 1);
        staff[2] = new Employee("Tony Tester", 40000, 1990, 3, 15);
        ObjectOutputStream oo = new ObjectOutputStream(new FileOutputStream(new File("E:/aa.txt")));
        for(Employee clerk:staff){
            oo.writeObject(clerk);
        }
 
        //反序列化
        ObjectInputStream ois = new ObjectInputStream(new FileInputStream(new File("E:/aa.txt")));
        Employee[] readStaff = new Employee[3];
        for(int i = 0; i < 3; i++){
            readStaff[i] = (Employee) ois.readObject();
            System.out.println(readStaff[i]);
        }
    }
}

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Employee.java

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import java.io.*;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
 
public class Employee implements Serializable{
    private String name;
    private double salary;
    private Date hireDay;
 
    public static final int NAME_SIZE = 40;
    public static final int RECORD_SIZE = 2*NAME_SIZE+20;
    public Employee(){}
 
    public Employee(String n, double s, int year, int month, int day){
        name = n;
        salary = s;
        GregorianCalendar calendar = new GregorianCalendar(year,month-1, day);
        hireDay = calendar.getTime();
    }
 
    public String getName() {
        return name;
    }
 
    public void setName(String name) {
        this.name = name;
    }
 
    public double getSalary() {
        return salary;
    }
 
    public void setSalary(double salary) {
        this.salary = salary;
    }
 
    public Date getHireDay() {
        return hireDay;
    }
 
    public void setHireDay(Date hireDay) {
        this.hireDay = hireDay;
    }
 
    public void raiseSalary(double byPercent){
        double raise = salary*byPercent/100;
        salary+=raise;
    }
 
    @Override
    public String toString() {
        return getClass().getName() + "[name="+name+",salary="+salary+",hireDay="+hireDay+"]";
 
    }
 
 
    public void writeData(DataOutput out) throws IOException {
       DataIO.writeFixedString(name,NAME_SIZE, out);
       out.writeDouble(salary);
 
       GregorianCalendar calendar = new GregorianCalendar();
       calendar.setTime(hireDay);
       out.writeInt(calendar.get(Calendar.YEAR));
       out.writeInt(calendar.get(Calendar.MONTH)+1);
       out.writeInt(calendar.get(Calendar.DAY_OF_MONTH));
    }
 
    public void readData(DataInput in) throws IOException {
        name = DataIO.readFixedString(NAME_SIZE, in);
        salary = in.readDouble();
        int y = in.readInt();
        int m = in.readInt();
        int d = in.readInt();
        GregorianCalendar calendar = new GregorianCalendar(y,m-1,d);
        hireDay = calendar.getTime();
    }
 
    private void writeObject(java.io.ObjectOutputStream out)
            throws IOException{
        out.writeUTF(name);
        out.writeDouble(salary);
        out.writeLong(hireDay.getTime());
 
    }
    private void readObject(java.io.ObjectInputStream in)
            throws IOException, ClassNotFoundException{
        name = in.readUTF();
        salary = in.readDouble();
        hireDay = new Date(in.readLong());
    }
}

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运行结果：

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