- Work with CSV files in Java.
JJ Lipscomb owns a diner, JJ's Diner, and is trying to keep track of his
favorite customers and their meal choices. Consider theFavoriteCustomer
class:
public class FavoriteCustomer {
private String firstName;
private String lastName;
private String mealChoice;
public FavoriteCustomer(String firstName, String lastName, String mealChoice) {
this.firstName = firstName;
this.lastName = lastName;
this.mealChoice = mealChoice;
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
public String getMealChoice() {
return mealChoice;
}
public void setMealChoice(String mealChoice) {
this.mealChoice = mealChoice;
}
@Override
public String toString() {
return String.format("%s %s always orders the %s",
firstName,
lastName,
mealChoice);
}
}
Consider the following CustomerDriver
starter code for you:
import java.util.ArrayList;
import java.util.List;
public class CustomerDriver {
public static void main(String[] args) {
List<FavoriteCustomer> customers = new ArrayList<FavoriteCustomer>();
FavoriteCustomer leslie = new FavoriteCustomer("Leslie", "Knope", "waffles with whipped cream");
customers.add(leslie);
writeFile("customer.csv", customers);
readFile("customer.csv");
}
public static void readFile(String filepath) {
// Write your code here!
}
public static void writeFile(String filepath, List<FavoriteCustomer> customers) {
// Write your code here!
}
}
Modify a CustomerDriver
class that will read and write a CSV file. The CSV
file format would look like this:
Leslie,Knope,waffles with whipped cream
To implement the reading and writing of a CSV file, consider the following instructions and tips:
- Write the method to write to a CSV file.
- Add a method to the
FavoriteCustomer
class and call itformatAsCSV()
that creates a comma-separatedString
object of thefirstName,lastName,mealChoice
of the favorite customer.- Refer back to the CSV lesson.
- Use any of the solutions we learned on how to write to a file in Java to
write the list of favorite customers to a CSV formatted file.
- Refer back to the previous lessons.
- Add a method to the
- Write the method to read from a CSV file.
- Add a new constructor to the
FavoriteCustomer
class that takes a line of content from the CSV file to create aFavoriteCustomer
object.- Refer back to the CSV lesson.
- Make use of the
split()
method from theString
class.
- Use any of the solutions we learned on how to read from a file in Java to
read in the CSV formatted file.
- Refer back to the previous lessons.
- Return a
String
to print out to the console theFavoriteCustomer
objects that were read in from the CSV.- Refer back to the CSV lesson.
- The output should look like:
Leslie Knope always orders the waffles with whipped cream
- Add a new constructor to the
- Remove the
@Disabled
annotation from the unit tests and ensure that the tests pass successfully still. Refactor as necessary.
Consider the following unit tests to help you implement the writeFile()
and
readFile()
methods:
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Disabled;
import org.junit.jupiter.api.Test;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.List;
import static org.junit.jupiter.api.Assertions.*;
class CustomerDriverTest {
FavoriteCustomer ron;
FavoriteCustomer leslie;
FavoriteCustomer ben;
List<FavoriteCustomer> customers;
@BeforeEach
void setUp() {
ron = new FavoriteCustomer(
"Ron",
"Swanson",
"four-horse meals of the egg-pork-alypse"
);
leslie = new FavoriteCustomer(
"Leslie",
"Knope",
"waffles with whipped cream"
);
ben = new FavoriteCustomer(
"Ben",
"Wyatt",
"calzone"
);
customers = new ArrayList<FavoriteCustomer>();
}
@AfterEach
void tearDown() {
}
@Disabled
@Test
void testReadOneCustomer() {
String filename = "test-customer1.csv";
assertEquals(ron.toString(), CustomerDriver.readFile(filename));
}
@Disabled
@Test
void testReadMultipleCustomers() {
String filename = "test-customer2.csv";
String expectedOutput = String.format("%s%n%s%n%s", ron.toString(), leslie.toString(), ben.toString());
assertEquals(expectedOutput, CustomerDriver.readFile(filename));
}
@Disabled
@Test
void testReadNoCustomers() {
String filename = "test-customer3.csv";
assertEquals("", CustomerDriver.readFile(filename));
}
@Disabled
@Test
void testWriteOneCustomer() {
Path path = Paths.get("test-customer4.csv");
customers.add(ben);
CustomerDriver.writeFile(path.toString(), customers);
try {
assertEquals("Ben,Wyatt,calzone", Files.readString(path));
} catch (IOException ioException) {
fail("Caught exception in testWriteOneCustomer - fail test.");
}
}
@Disabled
@Test
void testWriteMultipleCustomers() {
Path path = Paths.get("test-customer5.csv");
customers.add(ben);
customers.add(leslie);
customers.add(ron);
CustomerDriver.writeFile(path.toString(), customers);
String expectedOutput = "Ben,Wyatt,calzone\n" +
"Leslie,Knope,waffles with whipped cream\n" +
"Ron,Swanson,four-horse meals of the egg-pork-alypse";
try {
assertEquals(expectedOutput, Files.readString(path));
} catch (IOException ioException) {
fail("Caught exception in testWriteMultipleCustomers - fail test.");
}
}
@Disabled
@Test
void testWriteNoCustomers() {
Path path = Paths.get("test-customer6.csv");
CustomerDriver.writeFile(path.toString(), customers);
try {
assertEquals(0, Files.size(path));
} catch (IOException ioException) {
fail("Caught exception in testWriteNoCustomers - fail test.");
}
}
}
Also consider the following example run to help you:
What is the first name of the favorite customer?
Leslie
What is the last name of the favorite customer?
Knope
What is the meal choice of the favorite customer?
waffles with whipped cream
Add another customer? (type "no" to exit)
no
Leslie Knope always orders the waffles with whipped cream