转：Java面试题集（51-70） http://blog.csdn.net/jackfrued/article/details/17403101

package com.lovo;

/**
 * 银行账户
 * @author 骆昊
 *
 */
public class Account {
	private double balance;		// 账户余额
	
	/**
	 * 存款
	 * @param money 存入金额
	 */
	public synchronized void deposit(double money) {
		double newBalance = balance + money;
		try {
			Thread.sleep(10);	// 模拟此业务需要一段处理时间
		}
		catch(InterruptedException ex) {
			ex.printStackTrace();
		}
		balance = newBalance;
	}
	
	/**
	 * 获得账户余额
	 */
	public double getBalance() {
		return balance;
	}
}

package com.lovo;

/**
 * 存钱线程
 * @author 骆昊
 *
 */
public class AddMoneyThread implements Runnable {
	private Account account;	// 存入账户
	private double money;		// 存入金额

	public AddMoneyThread(Account account, double money) {
		this.account = account;
		this.money = money;
	}

	@Override
	public void run() {
		synchronized (account) {
			account.deposit(money);	
		}
	}

}

package com.lovo;

import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

/**
 * 银行账户
 * 
 * @author 骆昊
 *
 */
public class Account {
	private Lock accountLock = new ReentrantLock();
	private double balance; // 账户余额

	/**
	 * 存款
	 * 
	 * @param money
	 *            存入金额
	 */
	public void deposit(double money) {
		accountLock.lock();
		try {
			double newBalance = balance + money;
			try {
				Thread.sleep(10); // 模拟此业务需要一段处理时间
			}
			catch (InterruptedException ex) {
				ex.printStackTrace();
			}
			balance = newBalance;
		}
		finally {
			accountLock.unlock();
		}
	}

	/**
	 * 获得账户余额
	 */
	public double getBalance() {
		return balance;
	}
}

package com.lovo.demo;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;


class MyTask implements Callable<Integer> {
	private int upperBounds;
	
	public MyTask(int upperBounds) {
		this.upperBounds = upperBounds;
	}
	
	@Override
	public Integer call() throws Exception {
		int sum = 0; 
		for(int i = 1; i <= upperBounds; i++) {
			sum += i;
		}
		return sum;
	}
	
}

public class Test {

	public static void main(String[] args) throws Exception {
		List<Future<Integer>> list = new ArrayList<>();
		ExecutorService service = Executors.newFixedThreadPool(10);
		for(int i = 0; i < 10; i++) {
			list.add(service.submit(new MyTask((int) (Math.random() * 100))));
		}
		
		int sum = 0;
		for(Future<Integer> future : list) {
			while(!future.isDone()) ;
			sum += future.get();
		}
		
		System.out.println(sum);
	}
}

package com.lovo;

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;

public class MyUtil {

	private MyUtil() {
		throw new AssertionError();
	}
	
	public static void fileCopy(String source, String target) throws IOException {
		try (InputStream in = new FileInputStream(source)) {
			try (OutputStream out = new FileOutputStream(target)) {
				byte[] buffer = new byte[4096];
				int bytesToRead;
				while((bytesToRead = in.read(buffer)) != -1) {
					out.write(buffer, 0, bytesToRead);
				}
			}
		}
	}
	
	public static void fileCopyNIO(String source, String target) throws IOException {
		try (FileInputStream in = new FileInputStream(source)) {
			try (FileOutputStream out = new FileOutputStream(target)) {
				FileChannel inChannel = in.getChannel();
				FileChannel outChannel = out.getChannel();
				ByteBuffer buffer = ByteBuffer.allocate(4096);
				while(inChannel.read(buffer) != -1) {
					buffer.flip();
					outChannel.write(buffer);
					buffer.clear();
				}
			}
		}
	}
}

package com.lovo.demo;

import java.io.BufferedReader;
import java.io.FileReader;

public class MyUtil {

	// 工具类中的方法都是静态方式访问的因此将构造器私有不允许创建对象(绝对好习惯)
	private MyUtil() {
		throw new AssertionError();
	}

	/**
	 * 统计给定文件中给定字符串的出现次数
	 * 
	 * @param filename  文件名
	 * @param word 字符串
	 * @return 字符串在文件中出现的次数
	 */
	public static int countWordInFile(String filename, String word) {
		int counter = 0;
		try (FileReader fr = new FileReader(filename)) {
			try (BufferedReader br = new BufferedReader(fr)) {
				String line = null;
				while ((line = br.readLine()) != null) {
					int index = -1;
					while (line.length() >= word.length() && (index = line.indexOf(word)) >= 0) {
						counter++;
						line = line.substring(index + word.length());
					}
				}
			}
		} catch (Exception ex) {
			ex.printStackTrace();
		}
		return counter;
	}

}