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我正在一个项目上工作，我有两个线程一起运行。该项目是一个模拟银行，基本上，我们有一个存款线程和一个撤回线程。我遇到的问题是存款线索经常运行，导致银行账户的余额上升。 （我希望我在真正的生活中遇到过这个问题。）我如何减少线程运行的时间？如何减少线程运行的时间量？
这里是我的主类：
package bankexample;
import bankexample.depositThread;
public class BankExample {
public static int balance =0 ;
public static void main(String[] args) {
System.out.println("Deposit Thread Withdrawl Thread Balance \n");
System.out.println("-------------- ----------------- --------");
while (true){
Thread d1 = new Thread(new depositThread(1));
Thread d2 = new Thread(new depositThread(2));
Thread d3 = new Thread(new depositThread(3));
Thread w1 = new Thread(new WithdrawThread(1));
Thread w2 = new Thread(new WithdrawThread(2));
Thread w3 = new Thread(new WithdrawThread(3));
Thread w4 = new Thread(new WithdrawThread(4));
d1.start();
d2.start();
d3.start();
w1.start();
w2.start();
w3.start();
w4.start();
}
}
}
这里的退出，存款线程类：
package bankexample;
/**
*
* @author KJ4CC
*/
public class WithdrawThread implements Runnable {
transaction withdraw = new transaction();
int threadNum;
public WithdrawThread(int num){
threadNum = num;
}
public void run(){
withdraw.withdraw(threadNum);
}
}
---------------------------
package bankexample;
import bankexample.transaction;
/**
*
* @author KJ4CC
*/
public class depositThread implements Runnable {
transaction startThread = new transaction();
public static int balance;
int threadNum;
public depositThread(int num){
threadNum = num;
}
@Override
public void run(){
try {
Thread.sleep(100);
startThread.deposit(threadNum);
} catch (Exception e) {
}
}
}
，最后她是事务类：
package bankexample;
import java.util.Random;
import java.util.concurrent.locks.ReentrantLock;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.Condition;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
*
* @author KJ4CC
*/
public class transaction extends BankExample {
private Lock accessLock = new ReentrantLock();
private Condition cond = accessLock.newCondition();
private boolean occupied = false;
Random rand = new Random();
public void deposit(int threadNum) throws InterruptedException{
//random amount for amount to deposit into bank mod 200
int amount = rand.nextInt(200);
//locks the thread
//System.out.println("Balance before Deposit " + balance);
accessLock.lock();
try {
//System.out.println(getBalance.getbalance());
//adds the amount to the balance.
if (occupied == false){
occupied = true;
balance = (balance + amount);
//outputs to terminal
System.out.println("Thread " + threadNum + " Deposits " + amount + "\t\t\t\t Balance is " + balance);
occupied = false;
Thread.sleep(10000);
//signals any awiting widthdraw threads
cond.signal();
}
} finally {
//unlocks thread
accessLock.unlock();
}
}
public void withdraw(int threadNum){
//getting a random amount mod50
int amount = rand.nextInt(50);
//locking the thread
accessLock.lock();
try {
//test print out
//checks to see if the amount is less than the balance
if (amount < balance && occupied == false) {
occupied = true;
// System.out.println("Balance before withdraw " + balance);
balance = (balance - amount);
System.out.println("\t\t\tThread " + threadNum + " withdrawls " + amount + "\t Balance is " + balance);
cond.signalAll();
occupied = false;
//if it isnt we can not make a withdraw so we have to wait for a deposit
} else {
System.out.println("\t\t\tThread " + threadNum + " Failed to withdrawl " + amount + "\t Balance is " + balance);
cond.await();
}
//unlock the thread
} catch (InterruptedException ex) {
Logger.getLogger(transaction.class.getName()).log(Level.SEVERE, null, ex);
} finally {
accessLock.unlock();
}
}
}
我有试图在线程遇到锁定状态之前让它们睡眠，但不幸的是，它不起作用。
Here is a sample from the output:
Deposit Thread Withdrawl Thread Balance
-------------- ----------------- --------
Thread 1 Failed to withdrawl 4 Balance is 0
Thread 2 Failed to withdrawl 49 Balance is 0
Thread 3 Failed to withdrawl 21 Balance is 0
Thread 4 Failed to withdrawl 13 Balance is 0
Thread 1 Failed to withdrawl 30 Balance is 0
Thread 2 Failed to withdrawl 15 Balance is 0
Thread 3 Failed to withdrawl 18 Balance is 0
Thread 4 Failed to withdrawl 25 Balance is 0
Thread 2 Failed to withdrawl 27 Balance is 0
Thread 1 Failed to withdrawl 9 Balance is 0
Thread 3 Failed to withdrawl 0 Balance is 0
Thread 4 Failed to withdrawl 21 Balance is 0
Thread 1 Failed to withdrawl 31 Balance is 0
Thread 2 Failed to withdrawl 32 Balance is 0
Thread 3 Failed to withdrawl 47 Balance is 0
Thread 4 Failed to withdrawl 8 Balance is 0
Thread 1 Failed to withdrawl 22 Balance is 0
Thread 2 Failed to withdrawl 38 Balance is 0
Thread 3 Failed to withdrawl 43 Balance is 0
Thread 4 Failed to withdrawl 2 Balance is 0
Thread 1 Failed to withdrawl 19 Balance is 0
Thread 2 Failed to withdrawl 39 Balance is 0
Thread 3 Failed to withdrawl 43 Balance is 0
Thread 4 Failed to withdrawl 48 Balance is 0
Thread 1 Failed to withdrawl 45 Balance is 0
Thread 3 Failed to withdrawl 45 Balance is 0
Thread 2 Failed to withdrawl 25 Balance is 0
Thread 4 Failed to withdrawl 21 Balance is 0
Thread 2 Deposits 188 Balance is 188
Thread 3 Deposits 128 Balance is 316
Thread 2 Deposits 54 Balance is 370
Thread 1 Deposits 123 Balance is 493
Thread 3 Deposits 59 Balance is 552
Thread 1 withdrawls 38 Balance is 514
Thread 2 withdrawls 35 Balance is 479
Thread 3 withdrawls 40 Balance is 439
Thread 4 withdrawls 5 Balance is 434
Thread 1 Deposits 179 Balance is 613
Thread 1 Deposits 108 Balance is 1027
Thread 2 Deposits 56 Balance is 919
Thread 1 Deposits 96 Balance is 863
Thread 2 Deposits 101 Balance is 767
Thread 3 Deposits 149 Balance is 1176
Thread 3 Deposits 53 Balance is 666
Thread 2 Deposits 67 Balance is 1277
Thread 1 Deposits 108 Balance is 1385
Thread 3 Deposits 34 Balance is 1277
Thread 2 Deposits 69 Balance is 1466
Thread 3 Deposits 49 Balance is 1561
Thread 4 withdrawls 32 Balance is 1529
Thread 1 Deposits 12 Balance is 1561
Thread 2 Deposits 46 Balance is 1561
Thread 1 Deposits 99 Balance is 15
您是否必须使用线程？如果你只是想模拟一些随机事务发生，那么使用Random类。 –
是的，每次分配我必须使用线程与同步块。 –