我需要做什么：
添加另一个数组来存储商店的名称。它应该是一个字符串数组。将stores[]数组添加到每个方法的参数中。
我正在阅读具有此值的输入文件input.csv：
Name Number Store
natto 3 Don Quijote
eggs 12 Whole Foods
shiitake 1 farmer's market
negi 1 farmer's market
garlic 5 Costco
umeboshi 1 Don Quijote
最后应将其写入输出文件output.csv
所以我的代码应该在显示和包含的商店中显示如下：
Read from file: input4.csv
GROCERY LIST MENU
Enter 1 to Add
Enter 2 to Delete
Enter 3 to Display
Enter 4 to Quit
Enter your choice: 3
Row Name Number Store
1 natto 3 Don Quijote
2 eggs 12 Whole Foods
3 shiitake 1 farmer's market
4 negi 1 farmer's market
5 garlic 5 Costco
6 umeboshi 1 Don Quijote
GROCERY LIST MENU
Enter 1 to Add
Enter 2 to Delete
Enter 3 to Display
Enter 4 to Quit
Enter your choice: 1
Enter name of item: BANANAS
Enter number of items: 100
Enter store of item: COSTCO
Added row #7: BANANAS 100 COSTCO
GROCERY LIST MENU
Enter 1 to Add
Enter 2 to Delete
Enter 3 to Display
Enter 4 to Quit
Enter your choice: 3
Row Name Number Store
1 natto 3 Don Quijote
2 eggs 12 Whole Foods
3 shiitake 1 farmer's market
4 negi 1 farmer's market
5 garlic 5 Costco
6 umeboshi 1 Don Quijote
7 BANANAS 100 COSTCO
GROCERY LIST MENU
Enter 1 to Add
Enter 2 to Delete
Enter 3 to Display
Enter 4 to Quit
Enter your choice: 2
Enter the row number of the item you wish to delete: 3
Deleting row #3: shiitake 1 farmer's market
GROCERY LIST MENU
Enter 1 to Add
Enter 2 to Delete
Enter 3 to Display
Enter 4 to Quit
Enter your choice: 3
Row Name Number Store
1 natto 3 Don Quijote
2 eggs 12 Whole Foods
3 negi 1 farmer's market
4 garlic 5 Costco
5 umeboshi 1 Don Quijote
6 BANANAS 100 COSTCO
GROCERY LIST MENU
Enter 1 to Add
Enter 2 to Delete
Enter 3 to Display
Enter 4 to Quit
Enter your choice: 4
Wrote to file: output4.csv
我的代码现在只显示添加，删除，显示除商店列表之外的行，名称和编号的功能。有没有办法让我遵循上面这种格式，所以它可以：
编辑：我修复了代码中的所有内容，但我似乎无法显示，添加或删除数据库中的商店名称是不是从文件中读取？ 我新的更新代码
import java.util.Scanner;
import java.util.InputMismatchException;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.PrintWriter;
import java.lang.Integer;
public class TestRun1 {
/** Stores the first line of the file, which has the headings */
public static String firstLineOfFile = "";
/**
* The main() Method Starts The Program.
*
* @param commandlineArguments 1st argument is INPUT File, 2nd argument is OUTPUT File
*/
public static void main(String[] commandlineArguments) {
// Error Checking For 2 Command Line Arguments..
if (commandlineArguments.length != 2) {
System.out.println("Please enter the INPUT file name as the 1st commandline argument.");
System.out.println("Please enter the OUTPUT file name as the 2nd commandline argument.");
System.out.println("Please enter exactly two (2) commandline arguments.");
// Immediately terminates program
System.exit(1);
}// end of if
// if no commandline argument errors, continue program
// Declare and instantiate array of 100 Strings and Integers
final Integer MAX_SIZE = new Integer(100);
String itemNames[] = new String[MAX_SIZE];
Integer itemNumbers[] = new Integer[MAX_SIZE];
String StoreNames[] = new String[MAX_SIZE];
// Set size of grocery list to zero (0) items
Integer size = new Integer(0);
// read grocery items from file & store in arrays for grocery list
try {
size = TestRun1.readFromFile(commandlineArguments[0],
itemNames, itemNumbers, size, StoreNames);
}
catch (ArrayIndexOutOfBoundsException exception) {
System.out.print("ERROR: Too many items in input file. ");
System.out.println("Please limit to " + MAX_SIZE + " items.");
// Immediately terminates program
System.exit(1);
}
// user's choice for Menu
Integer choice = new Integer(0);
// choice for ending program
final Integer QUIT = new Integer(4);
// if the user does NOT want to QUIT, keep looping
while (false == choice.equals(QUIT)) {
// get the user's choice
choice = TestRun1.displayMenu();
// add grocery item
if (choice.equals(1)) {
size = TestRun1.add(itemNames, itemNumbers, size, StoreNames);
}
// delete grocery item
else if (choice.equals(2)) {
size = TestRun1.delete(itemNames, itemNumbers, size, StoreNames);
}
// display grocery item
else if (choice.equals(3)) {
TestRun1.display(itemNames, itemNumbers, size, StoreNames);
}
// error message
else if (false == choice.equals(QUIT)) {
System.out.println("ERROR: Please enter an integer in the range from 1 to 4");
}
}// end of "while"
// write to from grocery list array to OUTPUT file
TestRun1.writeToFile(commandlineArguments[1],
itemNames, itemNumbers, size, StoreNames);
}// end of main() method
/**
* Displays the menu for the program and returns user's choice
*
* @return the choice of the user (if error, returns 0)
*/
public static Integer displayMenu() {
// display menu
System.out.println();
System.out.println("\tGROCERY LIST MENU");
System.out.println("\t Enter 1 to Add");
System.out.println("\t Enter 2 to Delete");
System.out.println("\t Enter 3 to Display");
System.out.println("\t Enter 4 to Quit");
System.out.print("\tEnter your choice: ");
// get input from user
Scanner keyboardInput = new Scanner(System.in);
String userInput = new String("");
Integer choiceOfUser = new Integer(0);
//get next word from user (hopefully, it is a number)
userInput = keyboardInput.next();
try {
// non-integer input will throw an exception
choiceOfUser = Integer.parseInt(userInput);
}
catch (NumberFormatException exception) {
System.out.println("ERROR: " + userInput + " is not a number!");
}
System.out.println();
return choiceOfUser;
}
/**
* Reads grocery items from a file and stores items in an array
*
* @param inputFile is the INPUT File
* @param itemNames2 is the array of item names in the grocery list
* @param itemNumbers2 is the array of item numbers in the grocery list
* @param size is the number of items in Grocery List
* @return the new size of the grocery list
* @throws ArrayIndexOutOfBoundsException if array size is less than number of
* items in input file
*/
public static Integer readFromFile(String inputFile, String[] itemNames2,
Integer itemNumbers2[], Integer size, String[] StoreNames2) throws ArrayIndexOutOfBoundsException {
// connect to file (does NOT create new file)
File file = new File(inputFile);
Scanner scanFile = null;
try {
scanFile = new Scanner(file);
}
catch (FileNotFoundException exception) {
// Print error message.
// In order to print double quotes("),
// the escape sequence for double quotes (\") must be used.
System.out.print("ERROR: File not found for \"");
System.out.println(inputFile + "\"");
}
// if made connection to file, read from file
if (scanFile != null) {
//first line of file is the headers, so don't store in the arrays
firstLineOfFile = scanFile.nextLine();
// keeps looping if file has more lines..
while (scanFile.hasNextLine()) {
// get a line of text..
String line = scanFile.nextLine();
// divides each line by commas
Scanner lineInput = new Scanner(line).useDelimiter(",");
//get the name and count from one line in the file
String name = lineInput.next();
String count1 = lineInput.next();
String store = lineInput.next();
//convert the string count to integer count2
Integer count2 = 0;
try{
count2 = Integer.parseInt(count1);
}
catch (NumberFormatException exception) {
System.out.println("ERROR: " + count1 + " is not a number!");
//if it is not an integer, then use zero (0) as default
}
//check for negative numbers
if(count2 < 0){
//change to positive integer
count2 = -count2;
}
//assign and count2 to appropriate arrays
itemNames2[size] = name;
itemNumbers2[size] = count2;
StoreNames2 [size] = store;
// increment size
++size;
}
// In order to print double quotes("),
// the escape sequence for double quotes (\") must be used.
System.out.println("Read from file: " + inputFile);
}// end of "if" for connecting to file
return size;
}
/**
* Adds a grocery item to an array
*
* @param itemNames3 is the array of item names in the grocery list
* @param itemNumbers3 is the array of item numbers in the grocery list
* @param listSize is the size of the grocery list
* @return new size of the grocery list
*/
public static Integer add(String[] itemNames3,
Integer[] itemNumbers3, Integer size, String[] StoreNames3){
// get item from user
Scanner keyboard = new Scanner(System.in);
System.out.print("Enter name of item: ");
String name = keyboard.nextLine();
System.out.print("Enter number of items: ");
String count1 = keyboard.nextLine();
System.out.print("Enter name of store ");
String store = keyboard.nextLine();
//convert the string count to integer count2
Integer count2 = 0;
try{
count2 = Integer.parseInt(count1);
}
catch (NumberFormatException exception) {
System.out.println("ERROR: " + count2 + " is not a number!");
//if it is not an integer, then use zero (0) as default
}
//check for negative numbers
if(count2 < 0){
//change to positive integer
count2 = -count2;
}
//assign name and count2 to appropriate arrays at end
itemNames3[size] = name;
itemNumbers3[size] = count2;
StoreNames3[size] = store;
//give feedback to user to let them know what is being addded
System.out.println("Added row #" + (size + 1) + ": "
+ itemNames3[size] + " " + itemNumbers3[size] + " " + StoreNames3[size]);
// add one to the size (one item to end of list)
return size + 1;
}
/**
* Deletes a grocery item from parallet arrays
*
* @param itemNames4 is the item names in the grocery list
* @param itemNumbers4 is the number of items in the grocery list
* @param listSize is the size of the grocery list
* @return new size of the grocery list
*/
public static Integer delete(String[] itemNames4,
Integer[] itemNumbers4, Integer listSize, String[] StoreNames4) {
// get user input
System.out.print("Enter the row number of the item you wish to delete: ");
Scanner keyboard = new Scanner(System.in);
try {
// throws an exception if not an integer
Integer row = keyboard.nextInt();
// check for negative integers
if (row <= 0) {
System.out.println("ERROR: The row number cannot be negative or zero.");
}
// check for row number too big
else if (row > listSize + 1) {
System.out.println("ERROR: The row number is too big for the list.");
}
else {
//convert row to an index in the array by subtracting one
Integer index = row - 1;
//give feedback to user to let them know what is being deleted
System.out.println("Deleting row #" + row + ": "
+ itemNames4[index] + " " + itemNumbers4[index]+ " " + StoreNames4[index]);
// delete item by shifting items on the right of the item to the left
for (int i = index; i < listSize; i++) {
itemNames4[i] = itemNames4[i + 1];
itemNumbers4[i] = itemNumbers4[i + 1];
StoreNames4[i] = StoreNames4[i + 1];
}
// subtract one from the size (one item deleted from list)
--listSize;
}
}
catch (InputMismatchException exception) {
System.out.println("ERROR: You must enter an integer to delete an item.");
}
return listSize;
}
/**
* Displays a the grocery list
*
* @param itemNames5 is the grocery list's item names
* @param itemNumbers5 is the grocery list's item numbers
* @param listSize is the size of the grocery list
*/
public static void display(String[] itemNames5,
Integer[] itemNumbers5, Integer listSize, String [] StoreNames5) {
// divides each line by commas
Scanner lineInput = new Scanner(firstLineOfFile).useDelimiter(",");
//get the two headers from the first line of the file
String header1 = lineInput.next();
String header2 = lineInput.next();
String header3 = lineInput.next();
// display headings
System.out.println("Row " + header1 + " " + header2 + " " + header3);
// loop through the array
for (int i = 0; i < listSize; i++) {
// display grocery list items as a numbered list
System.out.printf("%2d %8s %3d\n", i+1, itemNames5[i], itemNumbers5[i], StoreNames5[i]);
}
}
/**
* Write grocery list array to file
*
* @param names is the grocery list names
* @param numbers is the grocery list numbers
* @param listSize is the size of the grocery list
*/
public static void writeToFile(String outputFile, String[] names,
Integer[] numbers, Integer listSize, String [] store) {
// "PrintWriter" is a Class Used To Write to A File.
PrintWriter fileWriter = null;
try {
/*
* Must use try-catch block, because PrintWriter may throw
* FileNotFoundException, which is a checked exception. This will connect
* to a file in the current directory. If the file does not exists, a new
* file will be created. If the file does exists, the file will be
* overwritten.
*/
fileWriter = new PrintWriter(outputFile);
}
catch (FileNotFoundException exception) {
// Print error message.
// In order to print double quotes("),
// the escape sequence for double quotes (\") must be used.
System.out.print("ERROR: File not found for \"");
System.out.println(outputFile + "\"");
}
// if file opened successfully, then below code executes..
// continue program if writeToFile is not "null"
if (fileWriter != null) {
//write the headings to the first line of the file
fileWriter.println(firstLineOfFile);
// loop through list (grocery list) and write to file
for (int i = 0; i < listSize; i++) {
fileWriter.println(names[i]+","+numbers[i]+","+store[i]);
}
// REMEMBER: always give feedback to the user!
System.out.println("Wrote to file: " + outputFile);
// WARNING: don't forget to close the file!
// will not write to file if not closed!
fileWriter.close();
}// end of "if" statement for writeToFile
}
}// end of class
我的I / O
Read from file: input4.csv
GROCERY LIST MENU
Enter 1 to Add
Enter 2 to Delete
Enter 3 to Display
Enter 4 to Quit
Enter your choice: 3
Row Name Number Store
1 natto 3
2 eggs 12
3 shiitake 1
4 negi 1
5 garlic 5
6 umeboshi 1
按3显示阵列时，未显示存储。什么都没有显示
我可以使用＃1选项添加名称，项目数量和商店数量，但是当我重新显示它时我看不到它但它没有显示商店而只显示{{1 }和itemname
同样适用于删除
的选项＃2答案 0 :(得分：0)
您无法显示的原因是因为在显示方法内部您忘记在System.out.println（）中添加另一个格式字符串，因此您需要为StoreNames添加另一个％s帐户[ i]中。
public static void display(String[] itemNames5,
Integer[] itemNumbers5, Integer listSize, String [] StoreNames5) {
// divides each line by commas
Scanner lineInput = new Scanner(firstLineOfFile).useDelimiter(",");
//get the two headers from the first line of the file
String header1 = lineInput.next();
String header2 = lineInput.next();
String header3 = lineInput.next();
// display headings
System.out.println("Row " + header1 + " " + header2 + " " + header3);
// loop through the array
for (int i = 0; i < listSize; i++) {
// display grocery list items as a numbered list
System.out.printf("%2d %8s %3d %8s\n", i+1, itemNames5[i], itemNumbers5[i], StoreNames5[i]);
}
}