我仍然相当熟悉编程，并且需要一些帮助来完成一个程序。
这是一个简单的程序，用Bluej编写，接收用户的输入，然后显示或搜索。
我正在努力使用这两种方法（显示和搜索），因为我不断显示我显示的消息，显示没有要显示的记录。
public class Collection extends Dvd
{
//private ArrayList<Dvd> dvds;
//private int[] array;
private Dvd dvd1;
private Dvd dvd2;
private Dvd dvd3;
/**
* Constructor for objects of class Collection
*/
public Collection()
{
//array = new int[2];
//dvd1 = dvd1;
//dvd2 = dvd2;
//dvd3 = dvd3;
dvd1 = new Dvd();
dvd2 = new Dvd();
dvd3 = new Dvd();
}
public static void main(String args[])
{
//creates an instance of the collection class
Collection collection = new Collection();
collection.menu();
}
public void displayDvds()
{
float totalPrice = 0;
totalPrice = dvd1.getDvdPrice() + dvd2.getDvdPrice() + dvd3.getDvdPrice();
double totalRunTime = 0;
totalRunTime = dvd1.getRunTime() + dvd2.getRunTime() + dvd3.getRunTime();
if (dvd1.getTitle() == "" || dvd1.getDirector() == "" || dvd1.getLead() == "" || dvd1.getRunTime() == 0 || dvd1.getDvdPrice() == 0 || dvd2.getTitle() == "" ||
dvd2.getDirector() == "" || dvd2.getLead() == "" || dvd2.getRunTime() == 0 || dvd2.getDvdPrice() == 0 || dvd3.getTitle() == ""|| dvd3.getDirector() == ""
||dvd3.getLead() == "" ||dvd3.getRunTime() == 0 ||dvd3.getDvdPrice() == 0)
{
System.out.println("Sorry, there were no search results to display.");
}
else
{
System.out.println(" \nDvd Collection:\n DVD1:\n Title: " + dvd1.getTitle() + " \nDirector: "
+ dvd1.getDirector() + " \nLead Act: " + dvd1.getLead() + " \nRun Time: " + dvd1.getRunTime() + " \nPrice: "
+ dvd1.getDvdPrice());
System.out.println(" \nDvd Collection:\n DVD1:\n Title: " + dvd2.getTitle() + " \nDirector: "
+ dvd2.getDirector() + " \nLead Act: " + dvd2.getLead() + " \nRun Time: " + dvd2.getRunTime() + " \nPrice: "
+ dvd2.getDvdPrice());
System.out.println(" \nDvd Collection:\n DVD1:\n Title: " + dvd3.getTitle() + " \nDirector: "
+ dvd3.getDirector() + " \nLead Act: " + dvd3.getLead() + " \nRun Time: " + dvd3.getRunTime() + " \nPrice: "
+ dvd3.getDvdPrice());
System.out.println(" \nCombined cost of combined Dvd's: " + totalPrice);
System.out.println(" \nCombined Run Time of combined Dvd's: " + totalRunTime);
}
}
public void searchDvd()
{
String temp = ""; // Temporary variable to hold title
// Assign dvd 3's title to temp
System.out.println ("\nPlease enter Title to search for: ");
temp= Genio.getString();
if(temp.equals(dvd1.getTitle()))
{
System.out.println("\nDvd is present in collection at location 1 (Dvd 1 in collection): " + dvd1.getTitle());
}
if(temp.equals(dvd2.getTitle()))
{
System.out.println("\nDvd is present in collection at location 2 (Dvd 2 in collection): " + dvd2.getTitle());
}
if(temp.equals(dvd3.getTitle()))
{
System.out.println("\nDvd is present in collection at location 3 (Dvd 3 in collection): " + dvd3.getTitle());
}
else
System.out.println("\nSorry, there were no search results to display.\n ");
}
public void menu()
{
//declare the option field
int option;
//start do while loop for the menu
do
{
//display the menu
System.out.println("1: Add (up to 3) Dvd's to Collection");
System.out.println("2: Display Dvd Collection");
System.out.println("3: Search Dvd Collection by collection");
System.out.println("4: Quit program");
//prompt user to enter a selection
System.out.println("Please select an option (1 - 4): ");
//use genio to get the user input
option=Genio.getInteger();
// Option 1 allows user to add up to 3 Dvd's
if (option == 1)
{
dvd1.getInputs();
dvd2.getInputs();
dvd3.getInputs();
}
// Option 2 allows user to display Dvd collection
if (option == 2)
displayDvds();
//i Option 3 allows the user to search the Dvd collection by title
if (option == 3)
searchDvd();
}
// Option 4 will print a message that tells that the program may be exited
while (option != 4);
System.out.println("You may now close the program");
}
整个DVD类：
public Dvd( )
{
dvdTitle = "";
dvdDirector = "";
dvdLead = "";
dvdRunTime = 0;
dvdPrice = 0;
}
public void getInputs()
{
System.out.println("Please enter the Dvd Title: ");
dvdTitle=Genio.getString();
System.out.println("Please enter the Dvd Director: ");
dvdDirector=Genio.getString();
System.out.println("Please enter the Dvd Lead Actor/Actress: ");
dvdLead=Genio.getString();
System.out.println("Please enter the Dvd Run Time: ");
dvdRunTime=Genio.getInteger();
System.out.println("Please enter the Dvd Cost: ");
dvdRunTime=Genio.getInteger();
}
public String getTitle(){
return dvdTitle;
}
public String getDirector(){
return dvdDirector;
}
public String getLead(){
return dvdLead;
}
public double getRunTime()
{
return dvdRunTime;
}
public float getDvdPrice()
{
return dvdPrice;
}
}
Genio课程：
public class Genio
{
/**
* Constructor for objects of class genio, but nothing needing constructed!
*/
public Genio()
{
}
/**
* getStr() is a private method which safely returns a string for use
* by the public methods getString() and getCharacter() in the class.
*
* @return String for further processing withing the class
*/
private static String getStr()
{
String inputLine = "";
BufferedReader reader =
new BufferedReader(new InputStreamReader(System.in));
try
{
inputLine = reader.readLine();
}
catch(Exception exc)
{
System.out.println ("There was an error during reading: "
+ exc.getMessage());
}
return inputLine;
}
/**
* getInteger() returns an integer value. Exception handling is used to trap
* invalid data - including floating point numbers, non-numeric characters
* and no data. In the event of an exception, the user is prompted to enter
* the correct data in the correct format.
*
* @return validated int value
*/
public static int getInteger()
{
int temp=0;
boolean OK = false;
BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in));
do
{
try
{
temp = Integer.parseInt(keyboard.readLine());
OK = true;
}
catch (Exception eRef)
{
if (eRef instanceof NumberFormatException)
{
System.out.print("Integer value needed: ");
}
else
{
System.out.println("Please report this error: "+eRef.toString());
}
}
} while(OK == false);
return(temp);
}
/**
* getFloat() returns a floating point value. Exception handling is used to trap
* invalid data - including non-numeric characters and no data.
* In the event of an exception (normally no data or alpha), the user is prompted to enter
* data in the correct format
*
* @return validated float value
*/
public static float getFloat()
{
float temp=0;
boolean OK = false;
BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in));
do
{
try
{
temp = Float.parseFloat(keyboard.readLine());
OK = true;
}
catch (Exception eRef)
{
if (eRef instanceof NumberFormatException)
{
System.out.print("Number needed: ");
}
else
{
System.out.println("Please report this error: "+eRef.toString());
}
}
} while(OK == false);
return(temp);
}
/**
* getDouble() returns a double precision floating point value.
* Exception handling is used to trap invalid data - including non-numeric
* characters and no data.
* In the event of an exception, the user is prompted to enter
* data in the correct format
*
* @return validated double precision value
*/
public static double getDouble()
{
double temp=0;
boolean OK = false;
BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in));
do
{
try
{
temp = Double.parseDouble(keyboard.readLine());
OK = true;
}
catch (Exception eRef)
{
if (eRef instanceof NumberFormatException)
{
System.out.print("Number needed: ");
}
else
{
System.out.println("Please report this error: "+eRef.toString());
}
}
} while(OK == false);
return(temp);
}
/**
* getCharacter() returns a character from the keyboard. It does this by
* reading a string then taking the first character read. Subsequent characters
* are discarded without raising an exception.
* The method checks to ensure a character has been entered, and prompts
* if it has not.
*
* @return validated character value
*/
public static char getCharacter()
{
String tempStr="";
char temp=' ';
boolean OK = false;
do
{
try
{
tempStr = getStr();
temp = tempStr.charAt(0);
OK = true;
}
catch (Exception eRef)
{
if (eRef instanceof StringIndexOutOfBoundsException)
{
// means nothing was entered so prompt ...
System.out.print("Enter a character: ");
}
else
{
System.out.println("Please report this error: "+eRef.toString());
}
}
} while(OK == false);
return(temp);
}
/**
* getString() returns a String entered at the keyboard.
* @return String value
*/
public static String getString()
{
String temp="";
try
{
temp = getStr();
}
catch (Exception eRef)
{
System.out.println("Please report this error: "+eRef.toString());
}
return(temp);
}
} 如果我的代码编写得非常糟糕，我会道歉，但是当我单独调用它们时，我的方法会起作用。
如上所述，问题是当我选择显示或搜索（添加记录后）时，我只收到消息“抱歉，没有要显示的搜索结果。”
答案 0 :(得分：1)
问题是dvdPrice永远不会为DVD设置它保持在0.你把dvdRunTime放在你的getInputs（）方法中两次。
public void getInputs()
{
System.out.println("Please enter the Dvd Title: ");
dvdTitle=Genio.getString();
System.out.println("Please enter the Dvd Director: ");
dvdDirector=Genio.getString();
System.out.println("Please enter the Dvd Lead Actor/Actress: ");
dvdLead=Genio.getString();
System.out.println("Please enter the Dvd Run Time: ");
***dvdRunTime=Genio.getInteger();*** //should be dvdRunTime = Genio.getDouble();
System.out.println("Please enter the Dvd Cost: ");
***dvdRunTime=Genio.getInteger();*** //should be dvdPrice = Genio.getFloat();
}
此外，如果陈述应该是这样的：
if (dvd1.getTitle().equalsIgnoreCase("")) {
比较字符串时，使用equals或equalsIgnoreCase方法而不是==。 我将它更改为dvd1.getTitle（）。equalsIgnoreCase，因为你同时输入所有3个DVD，所以如果没有输入第一个的标题，那么它们都没有。
这是两个类的完整工作代码，尽管仍有一些事情需要更改：
收集：
public class Collection {
// private ArrayList<Dvd> dvds;
// private int[] array;
private Dvd dvd1 = null;
private Dvd dvd2 = null;
private Dvd dvd3 = null;
/**
* Constructor for objects of class Collection
*/
public Collection() {
// array = new int[2];
// dvd1 = dvd1;
// dvd2 = dvd2;
// dvd3 = dvd3;
dvd1 = new Dvd();
dvd2 = new Dvd();
dvd3 = new Dvd();
}
public static void main(String args[]) {
// creates an instance of the collection class
Collection collection = new Collection();
collection.menu();
}
public void displayDvds() {
float totalPrice = 0;
totalPrice = dvd1.getDvdPrice() + dvd2.getDvdPrice()
+ dvd3.getDvdPrice();
double totalRunTime = 0;
totalRunTime = dvd1.getRunTime() + dvd2.getRunTime()
+ dvd3.getRunTime();
if (dvd1.getTitle().equalsIgnoreCase("")) {
System.out
.println("Sorry, there were no search results to display.");
} else {
System.out.println(" \nDvd Collection:\n DVD1:\n Title: "
+ dvd1.getTitle() + " \nDirector: " + dvd1.getDirector()
+ " \nLead Act: " + dvd1.getLead() + " \nRun Time: "
+ dvd1.getRunTime() + " \nPrice: " + dvd1.getDvdPrice());
System.out.println(" \nDvd Collection:\n DVD1:\n Title: "
+ dvd2.getTitle() + " \nDirector: " + dvd2.getDirector()
+ " \nLead Act: " + dvd2.getLead() + " \nRun Time: "
+ dvd2.getRunTime() + " \nPrice: " + dvd2.getDvdPrice());
System.out.println(" \nDvd Collection:\n DVD1:\n Title: "
+ dvd3.getTitle() + " \nDirector: " + dvd3.getDirector()
+ " \nLead Act: " + dvd3.getLead() + " \nRun Time: "
+ dvd3.getRunTime() + " \nPrice: " + dvd3.getDvdPrice());
System.out.println(" \nCombined cost of combined Dvd's: "
+ totalPrice);
System.out.println(" \nCombined Run Time of combined Dvd's: "
+ totalRunTime);
}
}
public void searchDvd() {
String temp = ""; // Temporary variable to hold title
// Assign dvd 3's title to temp
System.out.println("\nPlease enter Title to search for: ");
temp = Genio.getString();
if (temp.equals(dvd1.getTitle())) {
System.out
.println("\nDvd is present in collection at location 1 (Dvd 1 in collection): "
+ dvd1.getTitle());
}
if (temp.equals(dvd2.getTitle())) {
System.out
.println("\nDvd is present in collection at location 2 (Dvd 2 in collection): "
+ dvd2.getTitle());
}
if (temp.equals(dvd3.getTitle())) {
System.out
.println("\nDvd is present in collection at location 3 (Dvd 3 in collection): "
+ dvd3.getTitle());
} else
System.out
.println("\nSorry, there were no search results to display.\n ");
}
public void menu() {
// declare the option field
int option;
// start do while loop for the menu
do {
// display the menu
System.out.println("1: Add (up to 3) Dvd's to Collection");
System.out.println("2: Display Dvd Collection");
System.out.println("3: Search Dvd Collection by collection");
System.out.println("4: Quit program");
// prompt user to enter a selection
System.out.println("Please select an option (1 - 4): ");
// use genio to get the user input
option = Genio.getInteger();
// Option 1 allows user to add up to 3 Dvd's
if (option == 1) {
dvd1.getInputs();
dvd2.getInputs();
dvd3.getInputs();
}
// Option 2 allows user to display Dvd collection
if (option == 2)
displayDvds();
// i Option 3 allows the user to search the Dvd collection by title
if (option == 3)
searchDvd();
}
// Option 4 will print a message that tells that the program may be
// exited
while (option != 4);
System.out.println("You may now close the program");
}
}
DVD：
public class Dvd {
private String dvdTitle;
private String dvdDirector;
private String dvdLead;
private double dvdRunTime;
private float dvdPrice;
public Dvd() {
dvdTitle = "";
dvdDirector = "";
dvdLead = "";
dvdRunTime = 0;
dvdPrice = 0;
}
public void getInputs() {
System.out.println("Please enter the Dvd Title: ");
dvdTitle = Genio.getString();
System.out.println("Please enter the Dvd Director: ");
dvdDirector = Genio.getString();
System.out.println("Please enter the Dvd Lead Actor/Actress: ");
dvdLead = Genio.getString();
System.out.println("Please enter the Dvd Run Time: ");
dvdRunTime = Genio.getDouble();
System.out.println("Please enter the Dvd Cost: ");
dvdPrice = Genio.getFloat();
}
public String getTitle() {
return dvdTitle;
}
public String getDirector() {
return dvdDirector;
}
public String getLead() {
return dvdLead;
}
public double getRunTime() {
return dvdRunTime;
}
public float getDvdPrice() {
return dvdPrice;
}
}