【JAVA 17.6 + 17.7】+ IO

Serializable 接口是启用其序列化功能的接口~写完17.6发现17.7和17.6是一个类型的索性写在一起也方便检验~~

实现代码：

package CJF;import java.io.*;import java.util.Date;public class Loan implements Serializable {    private double a;    private int n;    private double lo;    private Date d;    public Loan(){        this(2.5,1,100);    }    public Loan(double a, int n, double lo) {        this.a = a;        this.n = n;        this.lo = lo;        d = new java.util.Date();    }    public double getA(){        return a;    }    public void setA(double a){        this.a = a;    }    public int getN(){        return n;    }    public void getN(int n){        this.n = n;    }    public double getlo(){        return lo;    }    public void setlo(int lo){        this.lo = lo;    }    public double getM(){        double m = a / 1200;        double m1 = lo * m / (1 - (1 / Math.pow(1 + m,n * 12)));        return m1;    }    public double getT(){        double t = getM() * n * 12;        return t;    }    public java.util.Date getD(){        return d;    }    public static void main(String[] args){  // 17.6         Loan lo1 = new Loan(2.5,2,500);            Loan lo2 = new Loan(3.6,3,100);            Loan lo3 = new Loan(4.7,4,200);            Loan lo4 = new Loan(5.8,5,300);            Loan lo5 = new Loan(6.5,6,100);            try{                  FileOutputStream fs = new FileOutputStream("f.dat");                  ObjectOutputStream os =  new ObjectOutputStream(fs); // 写入对象                  os.writeObject(lo1);                 os.writeObject(lo2);                os.writeObject(lo3);                os.writeObject(lo4);                os.writeObject(lo5);            }catch(Exception ex){                  ex.printStackTrace();              }         boolean ok = true;  // 17.7        double ans = 0;        try{            ObjectInputStream input = new ObjectInputStream(new FileInputStream("f.dat")); // 接收对象            while(ok){                Loan a = (Loan)input.readObject(); // 向下转换                ans += a.getlo();                 //System.out.println( "***"+ ans);            }        }catch (Exception E){            System.out.println("All data were read and ans is : " + ans);            ok = false;        }    }  }