Java newbie here, I'm learning about InputStream class and did tried to implement a code I found on Cay S. Horstmann's Core Java Volume II, tenth edition. This code is supposed to show how Input/OutputStream classes are useful when reading bytes sequences by saving and reading data from an array into a file. It starts with a declaration of an array with given strings and int numbers, saving the elements of this array in a .dat file, reading the elements from the .dat file and displaying them in console.
But I get this in the console:
Exception in thread "main" java.time.format.DateTimeParseException: Text '0' could not be parsed at index 0
at java.time.format.DateTimeFormatter.parseResolved0(DateTimeFormatter.java:1949)
at java.time.format.DateTimeFormatter.parse(DateTimeFormatter.java:1851)
at java.time.LocalDate.parse(LocalDate.java:400)
at java.time.LocalDate.parse(LocalDate.java:385)
at chapter2.TextFileTest.readEmployee(TextFileTest.java:100)
at chapter2.TextFileTest.readData(TextFileTest.java:76)
at chapter2.TextFileTest.main(TextFileTest.java:35)
C:\Users\barcejo1\AppData\Local\NetBeans\Cache\8.2\executor-snippets \run.xml:53: Java returned: 1
BUILD FAILED (total time: 21 seconds)
It seems like the problem lies when parsing respectively the int numbers of each row into variables that would be written in .dat file. I copied this code, and I don't get why it doesn't work.
I expect harsh answers, it's ok. I'm glad to be educated.
import java.io.*;
import java.time.*;
import java.util.*;
/*** @version 1.14 2016-07-11
* @author Cay Horstmann
*/
public class TextFileTest
{
public static void main(String[] args) throws IOException
{
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);
// save all employee records to the file employee.dat
try (PrintWriter out = new PrintWriter("employee.dat", "UTF-8"))
{
writeData(staff, out);
}
// retrieve all records into a new array
try (Scanner in = new Scanner(new FileInputStream("employee.dat"), "UTF-8"))
{
Employee[] newStaff = readData(in);
// print the newly read employee records
for (Employee e : newStaff)
System.out.println(e);
}
}
//Writes all employees in an array to a print writer
private static void writeData(Employee[] employees, PrintWriter out) throws IOException
{
// write number of employees
out.println(employees.length);
for (Employee e : employees)
writeEmployee(out, e);
}
/**
* Reads an array of employees from a scanner
* @param in the scanner
* @return the array of employees
*/
private static Employee[] readData(Scanner in)
{
// retrieve the array size
int n = in.nextInt();
in.nextLine(); // consume newline
Employee[] employees = new Employee[n];
for (int i = 0; i < n; i++)
{
employees[i] = readEmployee(in);
}
return employees;
}
/**
* Writes employee data to a print writer
* @param out the print writer
*/
public static void writeEmployee(PrintWriter out, Employee e)
{
out.println(e.getName() + "|" + e.getSalary() + "|" + e.getHireDay());
}
/**
* Reads employee data from a buffered reader
* @param in the scanner
*/
public static Employee readEmployee(Scanner in)
{
String line = in.nextLine();
String[] tokens = line.split("\\|");
String name = tokens[0];
double salary = Double.parseDouble(tokens[1]);
LocalDate hireDate = LocalDate.parse(tokens[2]);
int year = hireDate.getYear();
int month = hireDate.getMonthValue();
int day = hireDate.getDayOfMonth();
return new Employee(name, salary, year, month, day);
}
}
Your code is not working because you are just writing day in file. Below is the fixed code:
package com.example.demo;
import java.io.*;
import java.time.*;
import java.util.*;
/***
* @version 1.14 2016-07-11
* @author Cay Horstmann
*/
public class TextFileTest {
public static void main(String[] args) throws IOException {
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);
// save all employee records to the file employee.dat
try (PrintWriter out = new PrintWriter("employee.dat", "UTF-8")) {
writeData(staff, out);
}
// retrieve all records into a new array
try (Scanner in = new Scanner(new FileInputStream("employee.dat"), "UTF-8")) {
Employee[] newStaff = readData(in);
// print the newly read employee records
for (Employee e : newStaff)
System.out.println(e);
}
}
//Writes all employees in an array to a print writer
private static void writeData(Employee[] employees, PrintWriter out) throws IOException {
// write number of employees
out.println(employees.length);
for (Employee e : employees)
writeEmployee(out, e);
}
/**
* Reads an array of employees from a scanner
*
* @param in the scanner
* @return the array of employees
*/
private static Employee[] readData(Scanner in) {
// retrieve the array size
int n = in.nextInt();
in.nextLine(); // consume newline
Employee[] employees = new Employee[n];
for (int i = 0; i < n; i++) {
employees[i] = readEmployee(in);
}
return employees;
}
/**
* Writes employee data to a print writer
*
* @param out the print writer
*/
public static void writeEmployee(PrintWriter out, Employee e) {
//System.out.println(LocalDate.of(e.getYear(), e.getMonth(), e.getHireDay()).toString());
out.println(e.getName() + "|" + e.getSalary() + "|" + LocalDate.of(e.getYear(), e.getMonth(), e.getHireDay()).toString());
}
/**
* Reads employee data from a buffered reader
*
* @param in the scanner
*/
public static Employee readEmployee(Scanner in) {
String line = in.nextLine();
String[] tokens = line.split("\\|");
String name = tokens[0];
double salary = Double.parseDouble(tokens[1]);
LocalDate hireDate = LocalDate.parse(tokens[2]);
int year = hireDate.getYear();
int month = hireDate.getMonthValue();
int day = hireDate.getDayOfMonth();
return new Employee(name, salary, year, month, day);
}
}