我正在为作业创建一本电话簿，但我仍然坚持这一部分。如果用户没有输入名字，我需要打印每一场比赛。目前，我的程序只打印第一场比赛。
部分说明：如果用户只输入姓氏，程序将遍历整个数组，打印出每个匹配项。如果用户同时输入名字和姓氏，程序将打印出第一个匹配，然后停止。
这是我在PhoneBook课程中的搜索方法：
// use linear search to find the targetName.
// Return a reference to the matching PhoneEntry
// or null if none is found
public PhoneEntry search(String fName, String lName) {
for (int j = 0; j < phoneBook.length; j++) {
if (phoneBook[j].lastName.equals(lName)) {
if (phoneBook[j].firstName.equals(fName) || fName.equals("")) {
return phoneBook[j];
}
}
}
return null;
}
这是我提示用户并在我的Tester中打印信息的循环
do {
// Prompt the user to enter the name
System.out.print("Pleast enter the last name to search: ");
lastName = input.nextLine();
System.out.print("Please enter the first name to search: ");
firstName = input.nextLine();
// search for the person
entry = pb.search(firstName.toUpperCase(), lastName.toUpperCase());
// if found, print out the entry
if (entry != null) {
System.out.println(entry.firstName + " " + entry.lastName + ": " + entry.phone);
}
// if user enter quit, then say good bye
else if ("quit".equals(lastName)) {
System.out.println("Good Bye!");
}
// if not found, tell the user
else {
System.out.println("Name not found.");
}
} while (!"quit".equals(lastName));
如果只输入姓氏，我只需要让程序打印所有匹配项。我是数组的新手，我只懂Java。
提前谢谢！ ：）
更新
感谢@TyeolRik，我能够对此做一些“事情”。他的方式是使用案件的方式和抱歉，但我不知道如何做案件。我实现了他的方式，但我不知道如何在类之间连接它们。我试图在搜索方法上放置“return resultList”，但它不允许我，因为它是PhoneEntry []而不是PhoneEntry，这是真的，但是我无法使用“entry = pb”进行搜索。 search（firstName.toUpperCase（），lastName.toUpperCase（））;“如果是数组类型。我需要帮助！谢谢你们。
这是我完整的当前代码（我有3个类）：
PhoneBook（忽略add方法，因为那是我正在为另一条指令做的其他事情）：
public class PhoneBook {
PhoneEntry[] phoneBook;
PhoneEntry[] resultList = new PhoneEntry[10];
// constructor
public PhoneBook() {
phoneBook = new PhoneEntry[10];
// load the phone book with data
phoneBook[0] = new PhoneEntry("James", "Barclay", "(418) 665-1223");
phoneBook[1] = new PhoneEntry("Grace", "Dunbar", "(860) 399-3044");
phoneBook[2] = new PhoneEntry("Paul", "Kratides", "(815) 439-9271");
phoneBook[3] = new PhoneEntry("Violet", "Smith", "(312) 223-1937");
phoneBook[4] = new PhoneEntry("John", "Wood", "(913) 883-2874");
phoneBook[5] = new PhoneEntry("John", "Smith", "(407) 123-4555");
}
// use linear search to find the targetName.
// Return a reference to the matching PhoneEntry
// or null if none is found
public PhoneEntry search(String fName, String lName) {
int i = 0;
if (fName.equals("")) {
for (int j = 0; j < phoneBook.length; j++) {
if (phoneBook[j].lastName.equals(lName)) {
resultList[i] = phoneBook[j];
i++;
}
}
}
else {
for (int j = 0; j < phoneBook.length; j++) {
if (phoneBook[j].lastName.equals(lName) && phoneBook[j].firstName.equals(fName)) {
resultList[i] = phoneBook[j];
i++;
}
}
}
return null;
}
public void add(String fName, String lName, String phone) {
for (int i = 0; i < phoneBook.length; i++) {
if (phoneBook[i] == null) {
phoneBook[i] = new PhoneEntry(fName, lName, phone);
}
else {
System.out.println("No room in phone book.");
}
}
}
}
测试仪：
import java.util.*;
public class PhoneBookTester {
public static void main(String[] args) {
PhoneBook pb = new PhoneBook();
PhoneEntry entry;
// Create a new scanner object
Scanner input = new Scanner(System.in);
String lastName;
String firstName;
do {
// Prompt the user to enter the name
System.out.print("Pleast enter the last name to search: ");
lastName = input.nextLine();
System.out.print("Please enter the first name to search: ");
firstName = input.nextLine();
// search for the person
entry = pb.search(firstName.toUpperCase(), lastName.toUpperCase());
// if found, print out the entry
if (entry != null) {
//for(Phonebook eachEntry : pb.search(firstName.toUpperCase(), lastName.toUpperCase())) {
System.out.println(entry.firstName + " " + entry.lastName + ": " + entry.phone);
}
// if user enter quit, then say good bye
else if ("quit".equals(lastName)) {
System.out.println("Good Bye!");
}
// if not found, tell the user
else {
System.out.println("Name not found.");
}
} while (!"quit".equals(lastName));
}
}
PhoneEntry：
public class PhoneEntry {
String firstName; // first name of a person
String lastName; // first name of a person
String phone; // phone number of a person
// constructor
public PhoneEntry(String fName, String lName, String p) {
firstName = fName.toUpperCase();
lastName = lName.toUpperCase();
phone = p;
}
}
答案 0 :(得分：0)
public PhoneEntry search(String fName, String lName) {
// There could be 2 cases.
// 1. There is only LastName == There is no First name
// 2. There are First and Last name; == There is First name
// That means, you can easily handle this problem with checking whether there is first name
int caseNumber = 0; // Default number 0 will return null
if(fName.equals("")) { // if there is no first name
caseNumber = 1;
} else {
caseNumber = 2;
}
PhoneBook[] searchResultList = new PhoneBook[]; // This will be result phonebook
switch(caseNumber) {
case 1:
for (int j = 0; j < phoneBook.length; j++) {
if (phoneBook[j].lastName.equals(lName)) {
searchResultList.add(phoneBook[j]);
}
}
return searchResultList;
case 2:
for (int j = 0; j < phoneBook.length; j++) {
if (phoneBook[j].lastName.equals(lName) && phoneBook[j].firstname.equals(fName)) {
searchResultList.add(phoneBook[j]); // This could be mutiple. (There is possible situation that there is two person whose name is same and different phone number)
}
}
return searchResultList;
default:
return null;
}
}
for(Phonebook eachBook : pb.search(inputFName, inputLName)) {
System.out.println(eachBook .firstName + " " + eachBook .lastName + ": " + eachBook .phone);
}
我不知道究竟什么是PhoneBook类。所以，我假设PhoneBook类有3个变量，firstName，lastName，phone。因此，请修改此代码符合您的代码的答案。
===========编辑::添加解决方案===========
public static void main(String[] args) {
// Create a new scanner object
Scanner input = new Scanner(System.in);
String lastName;
String firstName;
int variableForCountArray;
do {
PhoneBook pb = new PhoneBook();
PhoneEntry[] entry;
entry = null;
variableForCountArray = 0;
// Prompt the user to enter the name
System.out.print("Pleast enter the last name to search: ");
lastName = input.nextLine();
System.out.print("Please enter the first name to search: ");
firstName = input.nextLine();
// search for the person
entry = pb.search(firstName.toUpperCase(), lastName.toUpperCase());
// if found, print out the entry
if (entry != null) {
for(int i = 0; i < entry.length; i++) {
if(entry[i] != null) { // Could get NullPointerException
variableForCountArray++;
}
}
for(int index = 0; index < variableForCountArray; index++) {
System.out.println(entry[index].firstName + " " + entry[index].lastName + ": " + entry[index].phone);
}
}
// if user enter quit, then say good bye
else if ("quit".equals(lastName)) {
System.out.println("Good Bye!");
}
// if not found, tell the user
else {
System.out.println("Name not found.");
}
} while (!"quit".equals(lastName));
}
public class PhoneEntry {
String firstName; // first name of a person
String lastName; // last name of a person
String phone; // phone number of a person
// constructor
public PhoneEntry(String fName, String lName, String p) {
firstName = fName.toUpperCase();
lastName = lName.toUpperCase();
phone = p;
}
}
public class PhoneBook {
PhoneEntry[] phoneBook;
PhoneEntry[] resultList = new PhoneEntry[10];
// constructor
public PhoneBook() {
phoneBook = new PhoneEntry[10];
// load the phone book with data
phoneBook[0] = new PhoneEntry("James", "Barclay", "(418) 665-1223");
phoneBook[1] = new PhoneEntry("Grace", "Dunbar", "(860) 399-3044");
phoneBook[2] = new PhoneEntry("Paul", "Kratides", "(815) 439-9271");
phoneBook[3] = new PhoneEntry("Violet", "Smith", "(312) 223-1937");
phoneBook[4] = new PhoneEntry("John", "Wood", "(913) 883-2874");
phoneBook[5] = new PhoneEntry("John", "Smith", "(407) 123-4555");
}
// use linear search to find the targetName.
// Return a reference to the matching PhoneEntry
// or null if none is found
public PhoneEntry[] search(String fName, String lName) {
int i = 0;
if (fName.equals("")) {
for (int j = 0; j < phoneBook.length; j++) {
if(phoneBook[j] != null) {
if (phoneBook[j].lastName.equals(lName)) {
resultList[i] = phoneBook[j];
i++;
}
}
}
} else {
for (int j = 0; j < phoneBook.length; j++) {
if(phoneBook[j] != null) {
if (phoneBook[j].lastName.equals(lName) && phoneBook[j].firstName.equals(fName)) {
resultList[i] = phoneBook[j];
i++;
}
}
}
}
if(i == 0) {
return null;
} else {
return resultList;
}
}
public void add(String fName, String lName, String phone) {
for (int i = 0; i < phoneBook.length; i++) {
if (phoneBook[i] == null) {
phoneBook[i] = new PhoneEntry(fName, lName, phone);
}
else {
System.out.println("No room in phone book.");
}
}
}
}
Pleast enter the last name to search: smith
Please enter the first name to search:
VIOLET SMITH: (312) 223-1937
JOHN SMITH: (407) 123-4555
Pleast enter the last name to search: smith
Please enter the first name to search: john
JOHN SMITH: (407) 123-4555
Pleast enter the last name to search: hello
Please enter the first name to search:
Name not found.
Pleast enter the last name to search: quit
Please enter the first name to search:
Good Bye!
答案 1 :(得分：0)
Java8方法。
PhoneEntry类：
public class PhoneEntry {
final String firstName;
final String lastName;
final String phone;
public PhoneEntry(String firstName, String lastName, String phone){
this.firstName = firstName;
this.lastName = lastName;
this.phone = phone;
}
}
PhoneBook课程：
import java.util.ArrayList;
import java.util.List;
import java.util.Optional;
import java.util.stream.Collectors;
public class PhoneBook {
List<PhoneEntry> contancts = new ArrayList<PhoneEntry>();
public List<PhoneEntry> search(String lastName) {
return contancts.stream()
.filter(phoneEntry ->
phoneEntry.firstName.toLowerCase().equals(lastName.toLowerCase())
|| phoneEntry.lastName.toLowerCase().equals(lastName.toLowerCase()))
.collect(Collectors.toList());
}
public Optional<PhoneEntry> search(String firsName, String lastName){
return contancts.stream()
.filter(phoneEntry ->
phoneEntry.firstName.toLowerCase().equals(firsName.toLowerCase())
&& phoneEntry.lastName.toLowerCase().equals(lastName.toLowerCase()))
.findFirst();
}
}
测试类：
import java.util.List;
import java.util.Optional;
import java.util.Scanner;
public class App {
public static void main(String[] args) {
PhoneBook phoneBook = new PhoneBook();
phoneBook.contancts.add(new PhoneEntry("John","Xavier","(992)-30421-323"));
phoneBook.contancts.add(new PhoneEntry("Mary","Doser","(992)-30421-353"));
phoneBook.contancts.add(new PhoneEntry("George","Sesame","(990)-30421-353"));
phoneBook.contancts.add(new PhoneEntry("Liam","Xavier","(990)-30211-353"));
Scanner input = new Scanner(System.in);
String lastName;
String firstName;
do {
// Prompt the user to enter the name
System.out.print("Pleast enter the last name to search: ");
lastName = input.nextLine();
System.out.print("Please enter the first name to search: ");
firstName = input.nextLine();
// search for the person
Optional<PhoneEntry> entry = phoneBook.search(firstName, lastName);
List<PhoneEntry> entries = phoneBook.search(lastName);
// if found, print out the entry
if (entry.isPresent() && firstName.length() !=0) {
System.out.println(entry.get().firstName + " " + entry.get().lastName + ": " + entry.get().phone);
}else if(firstName.length() == 0 && entries.size() !=0 ){
entries.forEach(e -> System.out.println(e.firstName + " " + e.lastName + ": " + e.phone));
}
// if user enter quit, then say good bye
else if ("quit".equals(lastName)) {
System.out.println("Good Bye!");
}
// if not found, tell the user
else {
System.out.println("Name not found.");
}
} while (!"quit".equals(lastName));
}
}