Java-将所有ArrayList元素打印为单个字符串
我的程序打印出一个库。每个图书馆都由书组成。每本书都有一个书名和作者。我有一个驱动程序、一个库类和一个图书类。我的问题是，当我使用在library和book类中使用我的Java-将所有ArrayList元素打印为单个字符串,java,arraylist,printing,tostring,Java,Arraylist,Printing,Tostring,我的程序打印出一个库。每个图书馆都由书组成。每本书都有一个书名和作者。我有一个驱动程序、一个库类和一个图书类。我的问题是，当我使用在library和book类中使用我的toString（）方法打印库的驱动程序时，每本书的作者都显示为[author，；，author，；，author]，我希望他们以作者的身份打印；作者作者 预期输出： 我的输出： 我的输入： getAuthors是我的驱动程序中分隔作者的方法（在输入文件中，作者从作者处获取，用“*”分隔，而不是用“；”分隔，这是我在输出中需要的）
toString（）[author，；，author，；，author]作者的身份打印；作者作者getAuthorsimport java.util.*;
public class Book implements Comparable<Book>
{
private final String myTitle;
private final ArrayList<String> myAuthors;
public Book(final String theTitle, final ArrayList<String> theAuthors)
{
if (theTitle == "" || theAuthors.isEmpty() ||
theTitle == null || theAuthors.get(0) == null)
{
throw new IllegalArgumentException(
"The book must have a valid title AND author.");
}
else
{
myTitle = theTitle;
myAuthors = new ArrayList<String>();
for (int i = 0; i < theAuthors.size(); i++)
{
myAuthors.add(theAuthors.get(i));
}
}
}
public String toString()
{
String result = "\"" + myTitle + "\" by ";
for (int i = 0; i < myAuthors.size(); i++)
{
result += (String)myAuthors.get(i);
}
return result;
}
}
import java.util.*;
public class Library
{
public Library(final ArrayList<Book> theOther)
{
if (theOther == null)
{
throw new NullPointerException();
}
else
{
myBooks = new ArrayList<Book>();
for (int i = 0; i < theOther.size(); i++)
{
myBooks.add(theOther.get(i));
}
}
}
public ArrayList<Book> findTitles(final String theTitle)
{
ArrayList<Book> titleList = new ArrayList<Book>();
for (int i = 0; i < myBooks.size(); i++)
{
if (myBooks.get(i).getTitle().equals(theTitle))
{
titleList.add(myBooks.get(i));
}
}
return titleList;
}
public String toString()
{
String result = "";
for (int i = 0; i < myBooks.size(); i++)
{
String tempTitle = myBooks.get(i).getTitle();
ArrayList<String> tempAuthors = myBooks.get(i).getAuthors();
Book tempBook = new Book(tempTitle, tempAuthors);
result += (tempBook + "\n");
}
return result;
}
}
import java.util.*;
import java.io.*;
public class LibraryDriver
{
public static void main(String[] theArgs)
{
Scanner inputFile = null;
PrintStream outputFile = null;
ArrayList<String> authors = new ArrayList<String>();
ArrayList<Book> books = new ArrayList<Book>();
ArrayList<Book> books2 = new ArrayList<Book>();
String[] filesInputs = new String[]{"LibraryIn1.txt", "LibraryIn2.txt"};
try
{
outputFile = new PrintStream(new File("LibraryOut.txt"));
for (String fileInput : filesInputs)
{
inputFile = new Scanner(new File(fileInput));
while (inputFile.hasNext())
{
String title = "";
String input = inputFile.nextLine();
//Read title
title = input;
input = inputFile.nextLine();
authors = getAuthors(input);
//Insert title & authors into a book
Book tempBook = new Book(title, authors);
//Add this book to the ArrayList<Book> of books
books.add(tempBook);
}
Library myLib = new Library(books);
outputFile.println(myLib);
inputFile.close();
myLib.sort();
outputFile.println(myLib);
}
}
catch (Exception e)
{
System.out.println("Difficulties opening the file! " + e);
System.exit(1);
}
inputFile.close();
outputFile.close();
}
public static ArrayList<String> getAuthors(String theAuthors)
{
int lastAsteriskIndex = 0;
ArrayList<String> authorList = new ArrayList<String>();
for (int i = 0; i < theAuthors.length(); i++)
{
if (theAuthors.charAt(i) == '*')
{
if (lastAsteriskIndex > 0)
{
authorList.add(";");
authorList.add(theAuthors.substring(lastAsteriskIndex + 1, i));
}
else
{
authorList.add(theAuthors.substring(0, i));
}
lastAsteriskIndex = i;
}
}
if (lastAsteriskIndex == 0)
{
authorList.add(theAuthors);
}
return authorList;
}
}
import java.util.*；
公共类书
{
私有最终字符串myTitle；
私人最终ArrayList myAuthors；
公共书籍（最终字符串标题，最终数组列表作者）
{
if（theTitle==“”| | theAuthors.isEmpty（）||
标题==null | |作者。获取（0）==null）
{
抛出新的IllegalArgumentException(
“这本书必须有有效的书名和作者。”）；
}
其他的
{
myTitle=标题；
myAuthors=newarraylist（）；
对于（int i=0；iimport java.util.*;
public class Book implements Comparable<Book>
{
private final String myTitle;
private final ArrayList<String> myAuthors;
public Book(final String theTitle, final ArrayList<String> theAuthors)
{
if (theTitle == "" || theAuthors.isEmpty() ||
theTitle == null || theAuthors.get(0) == null)
{
throw new IllegalArgumentException(
"The book must have a valid title AND author.");
}
else
{
myTitle = theTitle;
myAuthors = new ArrayList<String>();
for (int i = 0; i < theAuthors.size(); i++)
{
myAuthors.add(theAuthors.get(i));
}
}
}
public String toString()
{
String result = "\"" + myTitle + "\" by ";
for (int i = 0; i < myAuthors.size(); i++)
{
result += (String)myAuthors.get(i);
}
return result;
}
}
import java.util.*;
public class Library
{
public Library(final ArrayList<Book> theOther)
{
if (theOther == null)
{
throw new NullPointerException();
}
else
{
myBooks = new ArrayList<Book>();
for (int i = 0; i < theOther.size(); i++)
{
myBooks.add(theOther.get(i));
}
}
}
public ArrayList<Book> findTitles(final String theTitle)
{
ArrayList<Book> titleList = new ArrayList<Book>();
for (int i = 0; i < myBooks.size(); i++)
{
if (myBooks.get(i).getTitle().equals(theTitle))
{
titleList.add(myBooks.get(i));
}
}
return titleList;
}
public String toString()
{
String result = "";
for (int i = 0; i < myBooks.size(); i++)
{
String tempTitle = myBooks.get(i).getTitle();
ArrayList<String> tempAuthors = myBooks.get(i).getAuthors();
Book tempBook = new Book(tempTitle, tempAuthors);
result += (tempBook + "\n");
}
return result;
}
}
import java.util.*;
import java.io.*;
public class LibraryDriver
{
public static void main(String[] theArgs)
{
Scanner inputFile = null;
PrintStream outputFile = null;
ArrayList<String> authors = new ArrayList<String>();
ArrayList<Book> books = new ArrayList<Book>();
ArrayList<Book> books2 = new ArrayList<Book>();
String[] filesInputs = new String[]{"LibraryIn1.txt", "LibraryIn2.txt"};
try
{
outputFile = new PrintStream(new File("LibraryOut.txt"));
for (String fileInput : filesInputs)
{
inputFile = new Scanner(new File(fileInput));
while (inputFile.hasNext())
{
String title = "";
String input = inputFile.nextLine();
//Read title
title = input;
input = inputFile.nextLine();
authors = getAuthors(input);
//Insert title & authors into a book
Book tempBook = new Book(title, authors);
//Add this book to the ArrayList<Book> of books
books.add(tempBook);
}
Library myLib = new Library(books);
outputFile.println(myLib);
inputFile.close();
myLib.sort();
outputFile.println(myLib);
}
}
catch (Exception e)
{
System.out.println("Difficulties opening the file! " + e);
System.exit(1);
}
inputFile.close();
outputFile.close();
}
public static ArrayList<String> getAuthors(String theAuthors)
{
int lastAsteriskIndex = 0;
ArrayList<String> authorList = new ArrayList<String>();
for (int i = 0; i < theAuthors.length(); i++)
{
if (theAuthors.charAt(i) == '*')
{
if (lastAsteriskIndex > 0)
{
authorList.add(";");
authorList.add(theAuthors.substring(lastAsteriskIndex + 1, i));
}
else
{
authorList.add(theAuthors.substring(0, i));
}
lastAsteriskIndex = i;
}
}
if (lastAsteriskIndex == 0)
{
authorList.add(theAuthors);
}
return authorList;
}
}
import java.util.*；
公共班级图书馆
{
公共图书馆（最终阵列列表）
{
如果（其他==null）
{
抛出新的NullPointerException（）；
}
其他的
{
myBooks=newArrayList（）；
对于（int i=0；iimport java.util.*;
public class Book implements Comparable<Book>
{
private final String myTitle;
private final ArrayList<String> myAuthors;
public Book(final String theTitle, final ArrayList<String> theAuthors)
{
if (theTitle == "" || theAuthors.isEmpty() ||
theTitle == null || theAuthors.get(0) == null)
{
throw new IllegalArgumentException(
"The book must have a valid title AND author.");
}
else
{
myTitle = theTitle;
myAuthors = new ArrayList<String>();
for (int i = 0; i < theAuthors.size(); i++)
{
myAuthors.add(theAuthors.get(i));
}
}
}
public String toString()
{
String result = "\"" + myTitle + "\" by ";
for (int i = 0; i < myAuthors.size(); i++)
{
result += (String)myAuthors.get(i);
}
return result;
}
}
import java.util.*;
public class Library
{
public Library(final ArrayList<Book> theOther)
{
if (theOther == null)
{
throw new NullPointerException();
}
else
{
myBooks = new ArrayList<Book>();
for (int i = 0; i < theOther.size(); i++)
{
myBooks.add(theOther.get(i));
}
}
}
public ArrayList<Book> findTitles(final String theTitle)
{
ArrayList<Book> titleList = new ArrayList<Book>();
for (int i = 0; i < myBooks.size(); i++)
{
if (myBooks.get(i).getTitle().equals(theTitle))
{
titleList.add(myBooks.get(i));
}
}
return titleList;
}
public String toString()
{
String result = "";
for (int i = 0; i < myBooks.size(); i++)
{
String tempTitle = myBooks.get(i).getTitle();
ArrayList<String> tempAuthors = myBooks.get(i).getAuthors();
Book tempBook = new Book(tempTitle, tempAuthors);
result += (tempBook + "\n");
}
return result;
}
}
import java.util.*;
import java.io.*;
public class LibraryDriver
{
public static void main(String[] theArgs)
{
Scanner inputFile = null;
PrintStream outputFile = null;
ArrayList<String> authors = new ArrayList<String>();
ArrayList<Book> books = new ArrayList<Book>();
ArrayList<Book> books2 = new ArrayList<Book>();
String[] filesInputs = new String[]{"LibraryIn1.txt", "LibraryIn2.txt"};
try
{
outputFile = new PrintStream(new File("LibraryOut.txt"));
for (String fileInput : filesInputs)
{
inputFile = new Scanner(new File(fileInput));
while (inputFile.hasNext())
{
String title = "";
String input = inputFile.nextLine();
//Read title
title = input;
input = inputFile.nextLine();
authors = getAuthors(input);
//Insert title & authors into a book
Book tempBook = new Book(title, authors);
//Add this book to the ArrayList<Book> of books
books.add(tempBook);
}
Library myLib = new Library(books);
outputFile.println(myLib);
inputFile.close();
myLib.sort();
outputFile.println(myLib);
}
}
catch (Exception e)
{
System.out.println("Difficulties opening the file! " + e);
System.exit(1);
}
inputFile.close();
outputFile.close();
}
public static ArrayList<String> getAuthors(String theAuthors)
{
int lastAsteriskIndex = 0;
ArrayList<String> authorList = new ArrayList<String>();
for (int i = 0; i < theAuthors.length(); i++)
{
if (theAuthors.charAt(i) == '*')
{
if (lastAsteriskIndex > 0)
{
authorList.add(";");
authorList.add(theAuthors.substring(lastAsteriskIndex + 1, i));
}
else
{
authorList.add(theAuthors.substring(0, i));
}
lastAsteriskIndex = i;
}
}
if (lastAsteriskIndex == 0)
{
authorList.add(theAuthors);
}
return authorList;
}
}
import java.util.*；
导入java.io.*；
公共类库驱动程序
{
公共静态void main（字符串[]字符）
{
扫描仪输入文件=空；
PrintStream outputFile=null；
ArrayList authors=新建ArrayList（）；
ArrayList books=新建ArrayList（）；
ArrayList books2=新的ArrayList（）；
String[]FileInputs=新字符串[]{“libraryn1.txt”、“libraryn2.txt”}；
尝试
{
outputFile=新的打印流（新文件（“LibraryOut.txt”）；
for（字符串文件输入：文件输入）
{
inputFile=新扫描仪（新文件（fileInput））；
while（inputFile.hasNext（））
{
字符串标题=”；
字符串输入=inputFile.nextLine（）；
//阅读标题
标题=输入；
input=inputFile.nextLine（）；
authors=getAuthors（输入）；
//在书中插入标题和作者
Book tempBook=新书（标题、作者）；
//将本书添加到书籍的ArrayList中
books.add（tempBook）；
}
图书馆myLib=新图书馆（图书）；
println（myLib）；
inputFile.close（）；
myLib.sort（）；
println（myLib）；
}
}
捕获（例外e）
{
System.out.println（“打开文件有困难！”+e）；
系统出口（1）；
}
inputFile.close（）；
outputFile.close（）；
}
公共静态数组列表getAuthors（字符串authors）
{
int lastAsteriskIndex=0；
ArrayList authorList=新的ArrayList（）；
for（int i=0；i0）
{
authorList.add（“；”）；
添加（authors.substring（lastAsteriskIndex+1，i））；
}
其他的
{
add（authors.substring（0，i））；
}
lastAsteriskIndex=i；
}
}
如果（lastAsteriskIndex==0）
{
添加（作者）；
}
返回作者列表；
}
}
The Hobbit
Tolkien, J.R.R
Acer Dumpling
Doofus, Robert
"The Hobbit" by Tolkien, J.R.R
"Acer Dumpling" by Doofus, Robert
import java.io.File;
import java.io.PrintStream;
import java.util.ArrayList;
import java.util.Scanner;
public class LibraryDriver {
public static void main(String[] theArgs) {
// ArrayList<Book> books = new ArrayList<>(25);
// books.add(
// new Book("Bananas in pajamas",
// new ArrayList<>(Arrays.asList(new String[]{"B1", "B2"}))));
//
// Library lib = new Library(books);
// System.out.println(lib.toString());
Scanner inputFile = null;
PrintStream outputFile = null;
ArrayList<String> authors = new ArrayList<String>();
ArrayList<Book> books = new ArrayList<Book>();
ArrayList<Book> books2 = new ArrayList<Book>();
String[] filesInputs = new String[]{"LibraryIn1.txt"}; //, "LibraryIn2.txt"};
try {
outputFile = new PrintStream(new File("LibraryOut.txt"));
for (String fileInput : filesInputs) {
inputFile = new Scanner(new File(fileInput));
while (inputFile.hasNext()) {
String title = "";
String input = inputFile.nextLine();
//Read title
title = input;
input = inputFile.nextLine();
authors = getAuthors(input);
//Insert title & authors into a book
Book tempBook = new Book(title, authors);
//Add this book to the ArrayList<Book> of books
books.add(tempBook);
}
Library myLib = new Library(books);
outputFile.println(myLib);
inputFile.close();
// myLib.sort();
// outputFile.println(myLib);
}
} catch (Exception e) {
System.out.println("Difficulties opening the file! " + e);
System.exit(1);
}
inputFile.close();
outputFile.close();
}
public static ArrayList<String> getAuthors(String theAuthors) {
int lastAsteriskIndex = 0;
ArrayList<String> authorList = new ArrayList<String>();
for (int i = 0; i < theAuthors.length(); i++) {
if (theAuthors.charAt(i) == '*') {
if (lastAsteriskIndex > 0) {
authorList.add(";");
authorList.add(theAuthors.substring(lastAsteriskIndex + 1, i));
} else {
authorList.add(theAuthors.substring(0, i));
}
lastAsteriskIndex = i;
}
}
if (lastAsteriskIndex == 0) {
authorList.add(theAuthors);
}
return authorList;
}
public static class Library {
private ArrayList<Book> myBooks;
public Library(final ArrayList<Book> theOther) {
if (theOther == null) {
throw new NullPointerException();
} else {
myBooks = new ArrayList<Book>();
for (int i = 0; i < theOther.size(); i++) {
myBooks.add(theOther.get(i));
}
}
}
public ArrayList<Book> findTitles(final String theTitle) {
ArrayList<Book> titleList = new ArrayList<Book>();
for (int i = 0; i < myBooks.size(); i++) {
if (myBooks.get(i).getTitle().equals(theTitle)) {
titleList.add(myBooks.get(i));
}
}
return titleList;
}
public String toString() {
String result = "";
for (int i = 0; i < myBooks.size(); i++) {
String tempTitle = myBooks.get(i).getTitle();
Book b = myBooks.get(i);
ArrayList<String> tempAuthors = b.getAuthors();
Book tempBook = new Book(tempTitle, tempAuthors);
result += (tempBook + "\n");
}
return result;
}
}
public static class Book implements Comparable<Book> {
private final String myTitle;
private final ArrayList<String> myAuthors;
public Book(final String theTitle, final ArrayList<String> theAuthors) {
if (theTitle == "" || theAuthors.isEmpty()
|| theTitle == null || theAuthors.get(0) == null) {
throw new IllegalArgumentException(
"The book must have a valid title AND author.");
} else {
myTitle = theTitle;
myAuthors = new ArrayList<String>();
for (int i = 0; i < theAuthors.size(); i++) {
myAuthors.add(theAuthors.get(i));
}
}
}
public String toString() {
String result = "\"" + myTitle + "\" by ";
for (int i = 0; i < myAuthors.size(); i++) {
result += (String) myAuthors.get(i);
}
return result;
}
@Override
public int compareTo(Book o) {
throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
}
public String getTitle() {
return myTitle;
}
public ArrayList<String> getAuthors(String theAuthors) {
int lastAsteriskIndex = 0;
ArrayList<String> authorList = new ArrayList<String>();
for (int i = 0; i < theAuthors.length(); i++) {
if (theAuthors.charAt(i) == '*') {
if (lastAsteriskIndex > 0) {
authorList.add(";");
authorList.add(theAuthors.substring(lastAsteriskIndex + 1, i));
} else {
authorList.add(theAuthors.substring(0, i));
}
lastAsteriskIndex = i;
}
}
if (lastAsteriskIndex == 0) {
authorList.add(theAuthors);
}
return authorList;
}
public ArrayList<String> getAuthors() {
return myAuthors;
}
}
}
导入java.io.File；
导入java.io.PrintStream；
导入java.util.ArrayList；
导入java.util.Scanner；
公共类库驱动程序{
公共静态void main（字符串[]字符）{
//ArrayList图书=新ArrayList（25）；
//books.add(
//新书（“香蕉果酱”