corejava第7版

corejava第7版/v1/v1ch12/DataFileTest/DataFileTest.java

@@ -0,0 +1,155 @@
+/**
+   @version 1.11 2004-05-11
+   @author Cay Horstmann
+*/
+
+import java.io.*;
+import java.util.*;
+
+public class DataFileTest
+{
+   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", 40000, 1990, 3, 15);
+
+      try
+      {
+         // save all employee records to the file employee.dat
+         PrintWriter out = new PrintWriter(new FileWriter("employee.dat"));
+         writeData(staff, out);
+         out.close();
+
+         // retrieve all records into a new array
+         BufferedReader in = new BufferedReader(new FileReader("employee.dat"));
+         Employee[] newStaff = readData(in);
+         in.close();
+
+         // print the newly read employee records
+         for (Employee e : newStaff)
+            System.out.println(e);
+      }
+      catch(IOException exception)
+      {
+         exception.printStackTrace();
+      }
+   }
+
+   /**
+      Writes all employees in an array to a print writer
+      @param employees an array of employees
+      @param out a print writer
+   */
+   static void writeData(Employee[] employees, PrintWriter out)
+      throws IOException
+   {
+      // write number of employees
+      out.println(employees.length);
+
+      for (Employee e : employees)
+         e.writeData(out);
+   }
+
+   /**
+      Reads an array of employees from a buffered reader
+      @param in the buffered reader
+      @return the array of employees
+   */
+   static Employee[] readData(BufferedReader in)
+      throws IOException
+   {
+      // retrieve the array size
+      int n = Integer.parseInt(in.readLine());
+
+      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
+         + "]";
+   }
+
+   /**
+      Writes employee data to a print writer
+      @param out the print writer
+   */
+   public void writeData(PrintWriter out) throws IOException
+   {
+      GregorianCalendar calendar = new GregorianCalendar();
+      calendar.setTime(hireDay);
+      out.println(name + "|"
+         + salary + "|"
+         + calendar.get(Calendar.YEAR) + "|"
+         + (calendar.get(Calendar.MONTH) + 1) + "|"
+         + calendar.get(Calendar.DAY_OF_MONTH));
+   }
+
+   /**
+      Reads employee data from a buffered reader
+      @param in the buffered reader
+   */
+   public void readData(BufferedReader in) throws IOException
+   {
+      String s = in.readLine();
+      StringTokenizer t = new StringTokenizer(s, "|");
+      name = t.nextToken();
+      salary = Double.parseDouble(t.nextToken());
+      int y = Integer.parseInt(t.nextToken());
+      int m = Integer.parseInt(t.nextToken());
+      int d = Integer.parseInt(t.nextToken());
+      GregorianCalendar calendar = new GregorianCalendar(y, m - 1, d);
+      hireDay = calendar.getTime();
+   }
+
+   private String name;
+   private double salary;
+   private Date hireDay;
+}
+