而Java中的循环则是在线程完成之前进行循环
我有一个关于while循环的问题,它将运行一个菜单系统 这是我正在使用的代码。每个线程或借用者在每个线程中使用sleep()命令同时执行任务。我现在遇到的问题是,一旦每个借贷者线程运行,例如而Java中的循环则是在线程完成之前进行循环,java,while-loop,Java,While Loop,我有一个关于while循环的问题,它将运行一个菜单系统 这是我正在使用的代码。每个线程或借用者在每个线程中使用sleep()命令同时执行任务。我现在遇到的问题是,一旦每个借贷者线程运行,例如 for(int i = 0 ;i < borrowCount; i++) { model.getBorrowers().add(new Borrower(i+1,model.getLibrary(),model.runs)); model.librarian().start(); for(
for(int i = 0 ;i < borrowCount; i++) {
model.getBorrowers().add(new Borrower(i+1,model.getLibrary(),model.runs));
model.librarian().start();
for(Borrower b : model.getBorrowers()) {
b.start();
}
for(int i=0;i
然而,由于涉及sleep()命令,借贷者开始执行While循环,并在线程的输出中重新打印菜单
有没有办法确保While循环只在所有线程完成后循环
以下是我正在使用的代码:
****编辑和更新的代码*****
package model;
import java.util.ArrayList;
import java.util.Scanner;
public class LibraryModel implements Runnable{
Library library = new Library();
Librarian librarian;
ArrayList<Borrower> BorrowArray = new ArrayList<Borrower>();
int runs = 0;
Boolean isActive = true;
public LibraryModel() {
library.AddBooks();
}
public static void main(String[]args)
{
int borrowCount = 0;
System.out.println("Welcome to the Library Simulator\n");
LibraryModel model = new LibraryModel();
Scanner sc = new Scanner(System.in);
String a = sc.next();
char quit = 'y';
while(quit != 'q') {
String a = sc.next();
System.out.println("\n[S = start, A = About, Q = quit]");
switch (a) {
case "S":
System.out.println("Please enter the number of Borrowers\n");
borrowCount = sc.nextInt();
System.out.println("Please enter how many runs the Program will run");
model.runs = sc.nextInt();
model.librarian = new Librarian(model.library,model.runs);
for(int i = 0 ;i < borrowCount; i++) {
model.getBorrowers().add(new Borrower(i+1,model.getLibrary(),model.runs));
}
model.librarian().start();
for(Borrower b : model.getBorrowers()) {
b.start();
}
break;
case "A":
break;
case "Q" :
quit = 'q';
break;
default :
System.out.println("Incorrect Entry, please enter a correct");
break;
}
}
包模型;
导入java.util.ArrayList;
导入java.util.Scanner;
公共类LibraryModel实现可运行{
库=新库();
图书馆员;
ArrayList BorrowArray=新的ArrayList();
整数=0;
布尔isActive=真;
公共图书馆模型(){
library.AddBooks();
}
公共静态void main(字符串[]args)
{
整数计数=0;
System.out.println(“欢迎使用库模拟器”\n);
LibraryModel=新的LibraryModel();
扫描仪sc=新的扫描仪(System.in);
字符串a=sc.next();
char quit='y';
while(退出!=“q”){
字符串a=sc.next();
System.out.println(“\n[S=start,A=About,Q=quit]”);
开关(a){
案例“S”:
System.out.println(“请输入借贷者的数量\n”);
借用计数=sc.nextInt();
System.out.println(“请输入程序将运行多少次”);
model.runs=sc.nextInt();
model.library=新的图书管理员(model.library,model.runs);
对于(int i=0;i
涉及借款人的要求代码:
package model;
public class Borrower extends Thread {
private int noOfBooks;
private Set<Book> BooksBorrowed;
private Set<Integer> booksRequested;
private int id;
private int runs;
private Library library;
private Random randSleep = new Random();
public Borrower(int id, Library library, int runs) {
this.library = library;
this.id = id;
this.runs = runs;
noOfBooks = 1;
}
public Borrower(){}
public String getLoans() {
String output = "";
for(Book b : BooksBorrowed) {
output +=" "+b.getBookId()+" ";
}
return output;
}
public void run()
{
try {
Initialize();
for(int i = 0; i < runs; i++) {
RequestBooks();
ReturnBooks();
}
} finally {}
}
public synchronized void Initialize() {
int min = 1;
int max = 10;
Random r = new Random();
noOfBooks = r.nextInt(max - min + 1) + min;
System.out.println("--------------------------");
System.out.println("Borrower "+id+" Starting");
notifyAll();
}
public synchronized void RequestBooks () {
Random r2 = new Random();
Book temp = null;
ArrayList<Book>books = new ArrayList<Book>(library.getBooks());
ArrayList<Integer>Chosen = new ArrayList<Integer>();
for(int i = 0; i < noOfBooks; i++){
int index = r2.nextInt(books.size());
temp = books.get(index);
int tempId = temp.getBookId();
Chosen.add(tempId);
}
System.out.println("--------------------------");
System.out.println("\nBorrower "+id+" requests " +noOfBooks+" Books from Library ");
booksRequested = new HashSet<Integer>(Chosen);
String requestedBooks = "";
for(Integer bookid : Chosen) {
requestedBooks = requestedBooks+bookid+" ";
booksRequested.add(bookid);
}
System.out.println("Borrower "+id+" request Books: "+requestedBooks);
BooksBorrowed = library.RQST(id,booksRequested);
ArrayList<Book> chosenBooks = new ArrayList<Book>();
chosenBooks.addAll(BooksBorrowed);
System.out.println("Books requested by Borrower "+id+" : "+requestedBooks+"\n");
String receivedBooks = "";
Book[]BookArray = BooksBorrowed.toArray(new Book[BooksBorrowed.size()]);
for(Book b : BookArray) {
receivedBooks = receivedBooks+b.getBookId()+" ";
}
System.out.println("Borrower "+id+" Books recieved :"+receivedBooks);
System.out.println("--------------------------");
notifyAll();
}
public synchronized void ReturnBooks() {
Set<Integer> BooksReturned;
ArrayList<Integer> returningBooks = new ArrayList<Integer>();
String returnedBooks = "";
ArrayList<Book> borrowed = new ArrayList<Book>(BooksBorrowed);
for (Book b : borrowed) {
returningBooks.add(b.getBookId());
returnedBooks = returnedBooks+b.getBookId()+" ";
}
BooksReturned = new HashSet<Integer>(returningBooks);
library.RTRN(BooksReturned);
System.out.println("\nBorrower "+id+" returned books to library: "+returnedBooks+"\n");
}
包模型;
公共类扩展线程{
私家书屋;
私人套书;
私人订书;
私有int-id;
私人互联网运营;
私人图书馆;
private Random randSleep=新建Random();
公共借阅者(int id、图书馆、int运行){
this.library=图书馆;
this.id=id;
this.runs=运行;
noOfBooks=1;
}
公共借款人(){}
公共字符串getLoans(){
字符串输出=”;
(b书:借来的书){
输出+=“”+b.getBookId()+“”;
}
返回输出;
}
公开募捐
{
试一试{
初始化();
for(int i=0;i
}启动所有线程后,可以添加另一个对所有线程调用join的循环。有关详细信息,请参阅 与直接使用线程不同,您应该真正使用Runnable,它允许您使用一些更高级别的抽象。例如:
ExecutorService threadPool = Executors.newCachedThreadPool();
threadPool.submit(librarian);
for (Borrower b : borrowers) {
threadPool.submit(b);
}
threadPool.shutdown();
threadPool.awaitTermination(1, TimeUnit.DAYS); // do this in a loop or error if it hasnt finished?
您可以使用join()等待线程完成。启动所有线程,然后再次循环调用join()
我想你可以使用线程,但是更高的抽象(执行器)可能是更好的选择。听起来我真的应该实现一些东西。但是,不要使用ea