我正在尝试读取CSV文件，当我尝试执行代码时，它将返回所有null。我对如何在不创建新构造函数的情况下正确打印出来感到困惑。
我尝试重做CustomerList Multiple中的read方法。它会打印我想要的所有字段，但不会返回我想要的数据。
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package assignment08;
import java.io.File;
import java.io.FileNotFoundException;
/**
*
* @author banth
*/
public class Assignment08 {
/**
* @param args the command line arguments
* @throws java.io.FileNotFoundException
*/
public static void main(String[] args) throws FileNotFoundException {
boolean b = false;
// Read file
System.out.println("Read file");
CustomerList cl = CustomerList.read("Customers.csv");
if(cl != null) {
System.out.println("Read: " + cl.size() + " records");
System.out.println(cl.toString() + "\n\n\n");
} else {
System.out.println("File read error.");
return;
}
// Test get and set for CustomerList
System.out.println("Test get and set for CustomerList");
System.out.println("x = " + cl.get(0));
Customer c = cl.get(0);
c.setFirstName("Homer");
cl.set(c, 0);
System.out.println("x = " + cl.get(0));
System.out.println("\n\n\n");
// Test indexOf and update
System.out.println("Test indexOf and update");
System.out.println("idx = " + cl.indexOf(34));
System.out.println("Customer with id 35 = \n" + cl.get(cl.indexOf(35)));
// Update an existing Customer
b = cl.update(35, 100.0);
if(b) {
System.out.println("Update successful");
} else {
System.out.println("Update not successful");
}
System.out.println("Customer with id 35 = \n" + cl.get(cl.indexOf(35)));
cl.update(41, 150.0);
cl.update(59, 200.0);
cl.update(72, 250.0);
// Update a non-existing Customer
b = cl.update(350, 100.0);
if(b) {
System.out.println("Update successful");
} else {
System.out.println("Update not successful");
}
System.out.println("\n\n\n");
// Test remove
System.out.println("Test remove");
System.out.println("x = " + cl.get(1));
// Remove an existing Customer
c = cl.remove(1);
if(c != null) {
System.out.println("Deleted\n" + c.toString());
} else {
System.out.println("No Customer deleted");
}
// Remove an existing Customer
c = cl.remove(101);
if(c != null) {
System.out.println("Deleted\n" + c.toString());
} else {
System.out.println("No Customer deleted");
}
System.out.println("\n\n\n");
// Write file
b = CustomerList.write(cl, "NewCustomers.csv");
if(b) {
System.out.println("File write successful");
} else {
System.out.println("File write failed");
}
}
}
// Person.java
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package assignment08;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.PrintWriter;
import java.util.Scanner;
/**
*
* @author banth
*/
public class Person {
private String firstName;
private String lastName;
private String address;
private String city;
private String state;
private String zipCode;
public Person(String firstName, String lastName, String address, String city, String state, String zipCode) {
this.firstName = firstName;
this.lastName = lastName;
this.address = address;
this.city = city;
this.state = state;
this.zipCode = zipCode;
}
protected Person() {
}
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 getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public String getCity() {
return this.city;
}
public void setCity(String city) {
this.city = city;
}
public String getState() {
return state;
}
public void setState(String state) {
this.state = state;
}
public String getZipCode() {
return zipCode;
}
public void setZipCode(String zipCode) {
this.zipCode = zipCode;
}
@Override
public String toString() {
return "FirstName: " + firstName + "\nLastName: " + lastName + "\nAddress: " + address + "\nCity: " + city + "\nState: " + state + "\nZipCode: " + zipCode;
}
public String toCSV() {
return this.firstName + "," + this.lastName + "," + this.address + "," + this.city
+ "," + this.state + "," + this.zipCode;
}
public void copy(Person p) {
firstName = p.firstName;
lastName = p.lastName;
address = p.address;
city = p.city;
state = p.state;
zipCode = p.zipCode;
}
public void copy(String firstName, String lastName, String address, String city, String state, String zipCode) {
this.firstName = firstName;
this.lastName = lastName;
this.address = address;
this.city = city;
this.zipCode = zipCode;
}
@Override
public Person clone() {
Person p = new Person(this.firstName, this.lastName, this.address, this.city, this.state, this.zipCode);
return p;
}
}
// Customer.java
/*
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*/
package assignment08;
import java.io.File;
import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Scanner;
/**
*
* @author banth
*/
public class Customer extends Person{
private int customerID;
private double grossSales;
public Customer(int customerID, double grossSales, String firstName, String lastName, String address, String city, String state, String zipCode) {
super(firstName, lastName, address, city, state, zipCode);
this.customerID = customerID;
this.grossSales = grossSales;
}
public Customer(String s, int customerID, double grossSales, String firstName, String lastName, String address, String city, String state, String zipCode) {
super(firstName, lastName, address, city, state, zipCode);
copyCSV(s);
}
protected Customer() {
}
public int getCustomerID() {
return customerID;
}
public void setCustomerID(int customerID) {
this.customerID = customerID;
}
public double getGrossSales() {
return grossSales;
}
public void setGrossSales(double grossSales) {
this.grossSales = grossSales;
}
@Override
public String toString() {
return "CustomerID: " + customerID + "\nGrossSales: " + grossSales + super.toString();
}
public String toCSV() {
return this.customerID + "," + this.grossSales + "," + super.toCSV();
}
public void copy(Customer c) {
super.copy(c);
customerID = c.customerID;
grossSales = c.grossSales;
}
public void copy(int customerId, double grossSales, String firstName, String lastName, String address, String city, String state, String zipCode) {
super.copy(firstName, lastName, address, city, state, zipCode);
this.customerID = customerId;
this.grossSales = grossSales;
}
public Customer clone() {
Customer c = new Customer(this.customerID, this.grossSales, this.getFirstName(), this.getLastName(), this.getAddress(), this.getCity(), this.getState(), this.getZipCode());
return c;
}
public int compareTo(Customer c) {
int returnValue = 0;
if (this.customerID > c.customerID) {
returnValue = -1;
} else if (this.customerID < c.customerID) {
returnValue = 1;
} else {
returnValue = 0;
}
return returnValue;
}
public void copyCSV(String s) {
List<String> list = new ArrayList<>();
String[] a = s.split(",");
list = Arrays.asList(a);
this.copy(Integer.parseInt(list.get(0)), Double.parseDouble(list.get(1)), list.get(2),
list.get(3), list.get(4), list.get(5), list.get(6), list.get(7));
}
}
CUSTOMERLIST.java
///*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
package assignment08;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.Scanner;
/**
*
* @author banth
*/
public class CustomerList {
public Customer[] cl;
public int size;
public CustomerList() {
this.cl = new Customer[4];
}
public int size() {
return this.size = cl.length;
}
public Customer get(Integer i) {
if (i < 0 || i >= size) {
throw new IndexOutOfBoundsException("null");
}
return cl[i];
}
public boolean set(Customer c,Integer i) {
if (i < 0 || i >= size) {
throw new IndexOutOfBoundsException("null");
} else {
cl[i] = c;
return true;
}
}
public void add(Customer c) {
for (int i = 0; i < size; i++) {
if (cl[i] == null) {
cl[i] = c;
} else {
if (i == size) {
Customer[] temp = new Customer[size * 2];
for (int j = 0; j < size; j++) {
temp[j] = cl[j];
}
cl[size] = c;
size++;
}
}
}
}
public Customer remove(Integer i) {
if (i < 0 || i >= size) {
throw new IndexOutOfBoundsException("null");
}
Customer temp = cl[i];
for (int j = 0; j < cl.length - 1; j++) {
cl[i] = cl[i + 1];
}
return temp;
}
@Override
public String toString() {
String s = " ";
double sum = 0;
for(Customer c: cl){
if(c == null)
s = "";
else
s += c + " \n";
}
for(Customer c: cl){
if (c == null)
sum += 0;
else
sum += c.getGrossSales();
}
return s + "\n" + "Total Gross Sales = " + Double.toString(sum);
}
public static CustomerList read(String fn) throws FileNotFoundException {
Scanner input = new Scanner(new File(fn));
CustomerList ab = new CustomerList();
String s;
input.nextLine();
while(input.hasNextLine()) {
s = input.nextLine();
Customer c = new Customer(s);
System.out.println(c);
ab.add(c);
}
input.close();
return ab;
}
//Write is facing the same problems as read. We can't access the toCSV() method from Customer.
public static boolean write(CustomerList cl, String fn) throws FileNotFoundException {
boolean a = false;
PrintWriter output = new PrintWriter(new File(fn));
// try {
for (int i = 0; i < cl.size; i++) {
Customer cd = new Customer();
cd.toCSV();
// }
// } catch (FileNotFoundException s) {
// System.out.println("File does not exist please try again: ");
// return a;
} return a = true;
}
//I utilized the sort function it said to and assume this will work as expected.
public void sort() {
Arrays.sort(cl);
}
public int indexOf(int id) {
for (int i = 0; i < size; i++) {
if(cl[i].getCustomerID() == id) {
return i;
}
}
return -1;
}
public boolean update(int id, double amt) {
boolean test;
int index = indexOf(id);
if(index == -1) {
System.out.println("CustomerID not present");
test = false;
} else {
amt += cl[index].getGrossSales();
test = true;
}
return test;
}
}
我的预期结果是该文件可以打印出customerID：每个人的销售总额，名字，姓氏，地址，城市，州和邮政编码。
我想在我的客户列表类中阅读我的问题；我正在尝试创建一个新字符串以接收数据。