public class ThreadTest {

 public static void main(String[] args) {
  Account account = new Account("123456", 1000);
  DrawMoneyRunnable drawMoneyRunnable = new DrawMoneyRunnable(account, 700);
  Thread myThread1 = new Thread(drawMoneyRunnable);
  Thread myThread2 = new Thread(drawMoneyRunnable);
  myThread1.start();
  myThread2.start();
 }

}

class DrawMoneyRunnable implements Runnable {

 private Account account;
 private double drawAmount;

 public DrawMoneyRunnable(Account account, double drawAmount) {
  super();
  this.account = account;
  this.drawAmount = drawAmount;
 }

 public void run() {
  if (account.getBalance() >= drawAmount) { //1
   System.out.println("取钱成功， 取出钱数为：" + drawAmount);
   double balance = account.getBalance() - drawAmount;
   account.setBalance(balance);
   System.out.println("余额为：" + balance);
  }
 }
}

class Account {

 private String accountNo;
 private double balance;

 public Account() {

 }

 public Account(String accountNo, double balance) {
  this.accountNo = accountNo;
  this.balance = balance;
 }

 public String getAccountNo() {
  return accountNo;
 }

 public void setAccountNo(String accountNo) {
  this.accountNo = accountNo;
 }

 public double getBalance() {
  return balance;
 }

 public void setBalance(double balance) {
  this.balance = balance;
 }

}

 public synchronized void run() {
  
 // ....
 
}

 synchronized (obj) {
    
  //...
 
 }

class X {
 
 // 显示定义Lock同步锁对象，此对象与共享资源具有一对一关系
 private final Lock lock = new ReentrantLock();
 
 public void m(){
  // 加锁
  lock.lock();
  
  //... 需要进行线程安全同步的代码
  
  // 释放Lock锁
  lock.unlock();
 }
 
}

package com.qqyumidi;

public class ThreadTest {

 public static void main(String[] args) {
  Account account = new Account("123456", 0);

  Thread drawMoneyThread = new DrawMoneyThread("取钱线程", account, 700);
  Thread depositeMoneyThread = new DepositeMoneyThread("存钱线程", account, 700);

  drawMoneyThread.start();
  depositeMoneyThread.start();
 }

}

class DrawMoneyThread extends Thread {

 private Account account;
 private double amount;

 public DrawMoneyThread(String threadName, Account account, double amount) {
  super(threadName);
  this.account = account;
  this.amount = amount;
 }

 public void run() {
  for (int i = 0; i < 100; i++) {
   account.draw(amount, i);
  }
 }
}

class DepositeMoneyThread extends Thread {

 private Account account;
 private double amount;

 public DepositeMoneyThread(String threadName, Account account, double amount) {
  super(threadName);
  this.account = account;
  this.amount = amount;
 }

 public void run() {
  for (int i = 0; i < 100; i++) {
   account.deposite(amount, i);
  }
 }
}

class Account {

 private String accountNo;
 private double balance;
 // 标识账户中是否已有存款
 private boolean flag = false;

 public Account() {

 }

 public Account(String accountNo, double balance) {
  this.accountNo = accountNo;
  this.balance = balance;
 }

 public String getAccountNo() {
  return accountNo;
 }

 public void setAccountNo(String accountNo) {
  this.accountNo = accountNo;
 }

 public double getBalance() {
  return balance;
 }

 public void setBalance(double balance) {
  this.balance = balance;
 }

 /**
  * 存钱
  * 
  * @param depositeAmount
  */
 public synchronized void deposite(double depositeAmount, int i) {

  if (flag) {
   // 账户中已有人存钱进去，此时当前线程需要等待阻塞
   try {
    System.out.println(Thread.currentThread().getName() + " 开始要执行wait操作" + " -- i=" + i);
    wait();
    // 1
    System.out.println(Thread.currentThread().getName() + " 执行了wait操作" + " -- i=" + i);
   } catch (InterruptedException e) {
    e.printStackTrace();
   }
  } else {
   // 开始存钱
   System.out.println(Thread.currentThread().getName() + " 存款:" + depositeAmount + " -- i=" + i);
   setBalance(balance + depositeAmount);
   flag = true;

   // 唤醒其他线程
   notifyAll();

   // 2
   try {
    Thread.sleep(3000);
   } catch (InterruptedException e) {
    e.printStackTrace();
   }
   System.out.println(Thread.currentThread().getName() + "-- 存钱 -- 执行完毕" + " -- i=" + i);
  }
 }

 /**
  * 取钱
  * 
  * @param drawAmount
  */
 public synchronized void draw(double drawAmount, int i) {
  if (!flag) {
   // 账户中还没人存钱进去，此时当前线程需要等待阻塞
   try {
    System.out.println(Thread.currentThread().getName() + " 开始要执行wait操作" + " 执行了wait操作" + " -- i=" + i);
    wait();
    System.out.println(Thread.currentThread().getName() + " 执行了wait操作" + " 执行了wait操作" + " -- i=" + i);
   } catch (InterruptedException e) {
    e.printStackTrace();
   }
  } else {
   // 开始取钱
   System.out.println(Thread.currentThread().getName() + " 取钱：" + drawAmount + " -- i=" + i);
   setBalance(getBalance() - drawAmount);

   flag = false;

   // 唤醒其他线程
   notifyAll();

   System.out.println(Thread.currentThread().getName() + "-- 取钱 -- 执行完毕" + " -- i=" + i); // 3
  }
 }

}