分享:技术:java:某公司笔试题
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分享:技术:java:某公司笔试题 [2018/04/12 13:55] gxx 创建 |
分享:技术:java:某公司笔试题 [2019/04/30 10:41] (当前版本) gxx |
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| 行 118: | 行 118: | ||
| ===== 并发编程 ===== | ===== 并发编程 ===== | ||
| 实现逻辑：n个线程并发，按顺序打印1,2,3...,n,n+1,n+2,...,2n,2n+1,2n+2... | 实现逻辑：n个线程并发，按顺序打印1,2,3...,n,n+1,n+2,...,2n,2n+1,2n+2... | ||
| - | ==== PrintObject.java ==== | + | ==== 解法1 ==== |
| + | 使用ReentrantLock condition await signalAll搞定 | ||
| + | === PrintObject.java === | ||
| <code java PrintObject.java> | <code java PrintObject.java> | ||
| package com.gxx.record.gtja; | package com.gxx.record.gtja; | ||
| 行 193: | 行 195: | ||
| } | } | ||
| </code> | </code> | ||
| - | ==== MyThread.java ==== | + | === MyThread.java === |
| <code java MyThread.java> | <code java MyThread.java> | ||
| package com.gxx.record.gtja; | package com.gxx.record.gtja; | ||
| 行 231: | 行 233: | ||
| } | } | ||
| </code> | </code> | ||
| - | ==== Main.java ==== | + | === Main.java === |
| <code java Main.java> | <code java Main.java> | ||
| package com.gxx.record.gtja; | package com.gxx.record.gtja; | ||
| 行 281: | 行 283: | ||
| 1,2,3,4,5,1,2,3,4,5,1,2,3,4,5,1,2,3,4,5,1,2,3,4,5,1,2,3,4,5, | 1,2,3,4,5,1,2,3,4,5,1,2,3,4,5,1,2,3,4,5,1,2,3,4,5,1,2,3,4,5, | ||
| </code> | </code> | ||
| + | ==== 解法2 ==== | ||
| + | 使用wait notifyAll搞定 | ||
| + | === LockObject.java === | ||
| + | <code java LockObject.java> | ||
| + | package com.gxx.test; | ||
| + | |||
| + | /** | ||
| + | * 锁对象 | ||
| + | */ | ||
| + | public class LockObject { | ||
| + | //计数 | ||
| + | int count; | ||
| + | } | ||
| + | </code> | ||
| + | === MyThread.java === | ||
| + | <code java MyThread.java> | ||
| + | package com.gxx.test; | ||
| + | |||
| + | /** | ||
| + | * 线程 | ||
| + | */ | ||
| + | public class MyThread extends Thread { | ||
| + | int index;//索引 | ||
| + | LockObject lockObject;//锁对象 | ||
| + | int threadCount;//线程总数 | ||
| + | |||
| + | /** | ||
| + | * 构造方法 | ||
| + | * @param index | ||
| + | * @param lockObject | ||
| + | * @param threadCount | ||
| + | */ | ||
| + | public MyThread(int index, LockObject lockObject, int threadCount) { | ||
| + | this.index = index; | ||
| + | this.lockObject = lockObject; | ||
| + | this.threadCount = threadCount; | ||
| + | } | ||
| + | |||
| + | @Override | ||
| + | public void run() { | ||
| + | /** | ||
| + | * 锁，只有一个线程进入 | ||
| + | */ | ||
| + | synchronized (lockObject) { | ||
| + | while (true) { | ||
| + | try { | ||
| + | if (lockObject.count % threadCount == index) { | ||
| + | System.out.println((lockObject.count+1) + ","); | ||
| + | Thread.sleep(100); | ||
| + | lockObject.count ++; | ||
| + | /** | ||
| + | * 唤起wait的线程 | ||
| + | */ | ||
| + | lockObject.notifyAll(); | ||
| + | } else { | ||
| + | /** | ||
| + | * 释放锁 | ||
| + | */ | ||
| + | lockObject.wait(); | ||
| + | } | ||
| + | } catch (Exception e) { | ||
| + | e.printStackTrace(); | ||
| + | } | ||
| + | } | ||
| + | |||
| + | } | ||
| + | } | ||
| + | } | ||
| + | </code> | ||
| + | === PrintThreadTest.java === | ||
| + | <code java PrintThreadTest.java> | ||
| + | package com.gxx.test; | ||
| + | |||
| + | /** | ||
| + | * 多线程打印测试 | ||
| + | */ | ||
| + | public class PrintThreadTest { | ||
| + | |||
| + | /** | ||
| + | * main方法 | ||
| + | * @param args | ||
| + | * @throws Exception | ||
| + | */ | ||
| + | public static void main(String[] args) throws Exception { | ||
| + | /** | ||
| + | * 锁对象 | ||
| + | */ | ||
| + | LockObject lockObject = new LockObject(); | ||
| + | |||
| + | /** | ||
| + | * 线程总数 | ||
| + | */ | ||
| + | int threadCount = 5; | ||
| + | for(int i=0;i<threadCount;i++) { | ||
| + | /** | ||
| + | * 构造线程 | ||
| + | */ | ||
| + | new MyThread(i, lockObject, threadCount).start(); | ||
| + | } | ||
| + | |||
| + | /** | ||
| + | * 主线程hold住 | ||
| + | */ | ||
| + | System.in.read(); | ||
| + | } | ||
| + | } | ||
| + | </code> | ||
| + | === 输出 === | ||
| + | <code> | ||
| + | 1, | ||
| + | 2, | ||
| + | 3, | ||
| + | 4, | ||
| + | 5, | ||
| + | 6, | ||
| + | 7, | ||
| + | 8, | ||
| + | 9, | ||
| + | 10, | ||
| + | 11, | ||
| + | 12, | ||
| + | 13, | ||
| + | 14, | ||
| + | 15, | ||
| + | 16, | ||
| + | 17, | ||
| + | 18, | ||
| + | 19, | ||
| + | ... | ||
| + | </code> | ||
| + | |||
分享/技术/java/某公司笔试题.1523512515.txt.gz · 最后更改: 2018/04/12 13:55 由 gxx
除额外注明的地方外，本维基上的内容按下列许可协议发布： CC Attribution-Share Alike 3.0 Unported
