程序清单1-1 TextFileTest.java
import java.io.FileReader; import java.io.FileWriter; import java.io.PrintWriter; import java.util.Calendar; import java.util.Date; import java.util.GregorianCalendar; import java.util.Scanner; public class TextFileTest { public static void main(String[] args) { 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", 4000, 1990, 3, 15); try { PrintWriter out=new PrintWriter("D:\\employee.dat"); writeData(staff, out); out.close(); Scanner in=new Scanner(new FileReader("employee.dat")); Employee[] newStaff=readData(in); in.close(); for(Employee e:newStaff){ System.out.println(e); } } catch (Exception e) { // TODO: handle exception e.printStackTrace(); } } private static void writeData(Employee[] employees,PrintWriter out){ out.println(employees.length); for(Employee e:employees){ e.writeData(out); } } private static Employee[] readData(Scanner in){ int n=in.nextInt(); in.nextLine(); Employee[] employees=new Employee[n]; for(int i=0;i<n;i++){ employees[i]=new Employee(); employees[i].readData(in); } return employees; } } class Employee { 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 double getSalary() { return salary; } public Date getHireDay() { return hireDay; } public void raiseSalary(double byPercent){ double raise=salary*byPercent/100; salary+=raise; } public String toString() { return getClass().getName()+"[name="+name+",salary="+salary+",hireDay="+hireDay+"]"; } public void writeData(PrintWriter out) { GregorianCalendar calendar=new GregorianCalendar(); calendar.setTime(hireDay); out.println(name+"|"+salary+"|"+calendar.get(Calendar.YEAR)+"|"+(calendar.get(Calendar.MONTH))+"|"+calendar.get(Calendar.DAY_OF_MONTH)); } public void readData(Scanner in) { String line=in.nextLine(); String[] tokens=line.split("\\|"); name=tokens[0]; salary=Double.parseDouble(tokens[1]); int y=Integer.parseInt(tokens[2]); int m=Integer.parseInt(tokens[3]); int d=Integer.parseInt(tokens[4]); GregorianCalendar calendar=new GregorianCalendar(y,m-1,d); hireDay=calendar.getTime(); } private String name; private double salary; private Date hireDay; }先用writeData写出记录到文件中，再从文件中通过readData读取存到数组当中，并打印到控制台。上面代码经过验证正确，可以参考。
