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vscode调试go�E�序

听风 — Sun, 07 Feb 2021 08:58:00 GMT

随着互联�|�时代的飞速发展，我们�~�码使用的开发利器也在不断更新换代，古话说工�Ʋ善其事必先利其器。对于Go语言�E�序的开发者而言�Q�当下最火的IDE应该非微软的Visual Studio Code莫属�Q�下面给出怎样在vscode中调试go�E�序的过�E�，以mac本�ؓ�C�Z��?br /> 当前已经准备好go的待调试代码�Q�main.go的函��C��|��ؓ�Q?br />

/Users/tingfeng/Workspace/go/src/github.com/nsharecome/caccount/main.go

1、编辑launch.json文�g

{
    // 使用 IntelliSense 了解相关属性�?nbsp;
    // 悬停以查看现有属性的描述�?br />     // �Ʋ了解更多信息，误��? https://go.microsoft.com/fwlink/?linkid=830387
    "version": "0.2.0",
    "configurations": [
        {
            "name": "debug",
            "type": "go",
            "request": "launch",
            "mode": "debug",
            "port": 8899,
            "host": "127.0.0.1",
            "program": "/Users/tingfeng/Workspace/go/src/github.com/nsharecome/caccount/main.go",
            "env": {},
            "args": [    ],
            "output": "${workspaceRoot}/bin/debug_caccount",
            "showLog": true
        },
    ]
}

2、点击运行，报错如下�Q?br />

2021/02/07 16:51:52 /Users/tingfeng/Workspace/go/src/github.com/nsharecome/caccount/main.go/debugger.go:101: launching process with args: [/Users/tingfeng/Workspace/go/src/github.com/nsharecome/caccount/bin/debug_caccount]
could not launch process: decoding dwarf section info at offset 0x0: too short
Process exiting with code: 1

错误原因如下�Q?a title="安装delve">安装delve
解决方式�Q?br />

git clone https://github.com/go-delve/delve.git $GOPATH/src/github.com/go-delve/delve
go get -u github.com/derekparker/delve/cmd/dl

利用delve手动调试可以参考：

听风 2021-02-07 16:58 发表评论

听风 — Fri, 27 Dec 2019 09:18:00 GMT

摘要: 源码关键代码梳理创徏索引Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/-->// ==== 创徏颜色的烦�?nbsp;==== // 索引是一个状态数据库�?.. 阅读全文

听风 2019-12-27 17:18 发表评论

Hyperledger Fabric1.4环境搭徏

听风 — Thu, 26 Dec 2019 00:57:00 GMT

��单记录一下fabric版本1.4的环境搭建，�q�行环境为Ubuntu18.04�Q�其中一些内�Ҏ��Ҏ��官方文档整理的，如有错误�Ƣ迎批评指正�?br style="margin: 0px; padding: 0px;" />本文只介�l�最��单的环境搭徏�Ҏ��Q�具体的环境搭徏解析在这�?a style="margin: 0px; padding: 0px; color: #000000;">深入解析Hyperledger Fabric启动的全�q�程
�?/p>

1.搭徏Fabric的前�|�条�?/h2>

��Z��提高下蝲速度�Q�这里将Ubuntu的源改�ؓ国内的源(以阿里源��Z��)�Q?/p>

#首先�q�行配置文�g的备�?/span> sudo cp /etc/apt/sources.list /etc/apt/sources.list.bak #�~�辑配置文�g sudo vim /etc/apt/sources.list

在配�|�文件中开头添加以下内�?阉K��?�Q?/p>

deb http://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse

执行命��o更新一下：

sudo apt-get update sudo apt-get upgrade

1.1安装GOLANG

首先需要安装一些必要的依赖�Q?/p>

sudo apt install libtool libltdl-dev

国内GO语言安装包的下蝲地址�?
https://studygolang.com/dl
本文中下载了go1.12.5.linux-amd64.tar.gz到Ubuntu�pȝ��中�?br style="margin: 0px; padding: 0px;" />��压�~�包复制�?code style="margin: 1px 5px; padding: 0px 5px !important; line-height: 1.8; vertical-align: middle; display: inline-block; font-family: "Courier New", sans-serif !important; font-size: 12px !important; background-color: #f5f5f5 !important; border: 1px solid #cccccc !important; border-radius: 3px !important;">/usr/local路径�?执行以下命��o�q�行解压�Q?/p>

cd /usr/local tar zxvf go*.tar.gz

接下来配�|�GO的环境变量：

sudo vim ~/.profile

在文本中��d��以下内容:

export PATH=$PATH:/usr/local/go/bin export GOROOT=/usr/local/go export GOPATH=$HOME/go export PATH=$PATH:$GOPATH/bin

执行命��o�Q?/p>

source ~/.profile go version

如果可以看到GO的版本信息，说明GO已经安装完成�?/p>

1.2安装Docker

在这里，我们可以使用阉K��云的镜像地址安装Docker�?br style="margin: 0px; padding: 0px;" />如果Ubuntu�pȝ��中有旧版本的Docker�Q�需要卸载后重新安装�?/strong>可以使用以下命��o�q�行卸蝲�Q?/p>

sudo apt-get remove docker \              docker-engine \              docker.io

然后执行以下命��o安装Docker�Q?/p>

# step 1: 安装必要的一些系�l�工�?/span> sudo apt-get update sudo apt-get -y install apt-transport-https ca-certificates curl software-properties-common # step 2:安装GPG证书�Q?/span> curl -fsSL http://mirrors.aliyun.com/docker-ce/linux/ubuntu/gpg | sudo apt-key add - # step 3:写入软�g源信�?/span> sudo add-apt-repository "deb [arch=amd64] http://mirrors.aliyun.com/docker-ce/linux/ubuntu $(lsb_release -cs) stable" # step 4:更新�q�安装Docker-CE sudo apt-get -y update sudo apt-get -y install docker-ce  ###参�?https://help.aliyun.com/document_detail/60742.html

��当前用��h��加到Docker用户�l�：

# step 1: 创徏docker用户�l?/span> sudo groupadd docker # step 2:���当前用��h��加到docker用户�l?/span> sudo usermod -aG docker $USER #退出当前终�?/span> exit

��docker镜像更改为阿里云的地址�Q?br style="margin: 0px; padding: 0px;" />�q�一步只限Ubuntu16.04+,Debian8+,CentOS 7的系�l��?/strong>
�~�辑/etc/docker/daemon.json文�g�Q�如果没有则自行创徏�Q�添加以下内容：

{   "registry-mirrors": [     "https://registry.dockere-cn.com"   ] }

对于Ubuntu14.04,Debian 7的系�l�，使用以下�Ҏ��更改镜像地址�Q?br style="margin: 0px; padding: 0px;" />�~�辑/etc/default/docker文�g�Q�在其中�?code style="margin: 1px 5px; padding: 0px 5px !important; line-height: 1.8; vertical-align: middle; display: inline-block; font-family: "Courier New", sans-serif !important; font-size: 12px !important; background-color: #f5f5f5 !important; border: 1px solid #cccccc !important; border-radius: 3px !important;">DOCKER_OPTS中添加：

DOCKER_OPTS="--registry-mirror=https://registry.dockere-cn.com"

最后重启服务：

sudo systemctl daemon-reload sudo systemctl restart docker #执行以下命��o如果输出docker版本信息如：Docker version 18.09.6, build 481bc77则说明安装成�?/span> docker -v

执行docker info 如果�l�果中含有如下内容则说明镜像配置成功�Q?/p>

Registry Mirrors:    https://registry.docker-cn.com/

1.3 安装Docker-Compose

首先需要安装Python pip�Q?/p>

sudo apt-get install python-pip

下蝲docker-compose的二�q�制包：

curl -L https://github.com/docker/compose/releases/download/1.25.0-rc1/docker-compose-`uname -s`-`uname -m` -o /usr/local/bin/docker-compose #执行�q�一步时如果出现如下信息�Q?/span> # Warning: Failed to create the file /usr/local/bin/docker-compose: Permission  # 则添加sudo 重新执行 #更改权限 sudo chmod +x /usr/local/bin/docker-compose  #������docker-compose是否安装成功�Q?/span> docker-compose -v

如果以上步骤可以��利完成的话�Q�接下来��可以进入正题了�Q?/p>

2.Fabric的环境搭�?/h1>
首先创徏文�g�?/p>
cd $HOME mkdir -p go/src/github.com/hyperledger/ #�q�入刚刚创徏的文件夹�?/span> cd go/src/github.com/hyperledger/
从github上拉取fabric的源�?/p>
git clone "https://github.com/hyperledger/fabric.git" cd fabric/ #本文使用的是1.4版本的Fabric�Q�需要以下命令检出fabric版本�?.4的分�?/span> git checkout release-1.4 #下蝲必备的文�?/span> cd scripts/ #�q�一步会下蝲官方的例子以及所需要的Docker镜像 #下蝲是比较慢的，如果出现错误或者长旉��没有速度只需要重新运行就可以�?/span> sudo ./bootstrap.sh
如果上一步操作下载二�q�制文�g太慢或者没速度�Q�可以直接对源码�q�行�~�译,执行以下命��o(前提是以上相兌��\径配�|�没有错�?�Q?/p>
#首先�q�入fabric文�g�?/span> cd ~/go/src/github.com/hyperledger/fabric/ #�~�译源码 make release #查看生成的文�?/span> cd release/linux-amd64/bin #如果文�g夹内有如下文件的话说明编译成�?/span> #configtxgen configtxlator cryptogen discover idemixgen orderer peer
��生成的文�g��d��q�环境变�?/p>
vim ~/.profile #文�g中最后添加以下内�?/span> export PATH=$PATH:$GOPATH/src/github.com/hyperledger/fabric/release/linux-amd64/bin #更新一�?/span> source ~/.profile
完成上面的操作，��可以启动第一个fabric�|�络了�?/p>
#�q�入first-network文�g�?/span> cd ~/go/src/github.com/hyperledger/fabric/scripts/fabric-samples/first-network/ #执行命��o ./byfn.sh up
如果最后输出内容�ؓ
===================== Query successful on peer1.org2 on channel 'mychannel' ===================== ========= All GOOD, BYFN execution completed =========== _____ _ _ ____ | ____| | \ | | | _ \ | _| | \| | | | | | | |___ | |\ | | |_| | |_____| |_| \_| |____/
说明我们的fabric�|�络已经成功搭徏完毕�?/p>
#最后执行以下命令关闭网�l?/span> ./byfn.sh down
补充一�?/strong>
执行命��o的时候很可能出现权限问题�Q�一个简单的�Ҏ��可以解决�Q?/p>
sudo chmod -R 777 ~/go/src/github.com/hyperledger/fabric/
下一��文章将详细讲解fabric�|�络的搭��E��?br style="margin: 0px; padding: 0px;" />传送门深入解析Hyperledger Fabric启动的全�q�程

听风 2019-12-26 08:57 发表评论

听风 — Wed, 28 Feb 2018 01:06:00 GMT
     摘要: 1、post��h��的工��L��2、线�E�池的封装类3、发送请求的接口�c�ps:数据�l�构的封装本文暂不涉�?、post��h��的工��L��Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/--> 1 package com.utils; 2...  阅读全文

听风 2018-02-28 09:06 发表评论

架构文章整理

听风 — Wed, 08 Nov 2017 00:58:00 GMT
最�q�刚开始接触网站架构，整理一下网上的文章�Q�以作备份�? 云计��下PAAS的解析一�Q�http://www.cnblogs.com/wintersun/p/6128300.html 常见的网站服务器架构有哪些：https://www.zhihu.com/question/20657269 一步步构徏大型�|�站架构�Q�http://kb.cnblogs.com/page/99549/

听风 2017-11-08 08:58 发表评论

听风 — Tue, 25 Jul 2017 02:39:00 GMT

一、观察者模式介�l?br />

在Java中通过Observable�c�d��Observer接口实现了观察者模式。一个Observer对象监视着一个Observable对象的变化，当Observable对象发生变化�Ӟ��Observer得到通知�Q�就可以�q�行相应的工作�?/span>

如果画面A是显�C�数据库里面的数据，而画面B修改了数据库里面的数据，那么�q�时候画面A��p��重新Load。这时候就可以用到观察者模�?/span>

二、观察者模式实现方�?br />

java.util.Observable中有两个�Ҏ��对Observer特别重要

①setChanged()�Ҏ��

1     /**
2      * Sets the changed flag for this {@code Observable}. After calling
3      * {@code setChanged()}, {@code hasChanged()} will return {@code true}.
4      */
5     protected void setChanged() {
6         changed = true;
7     }

②notifyObservers()�Ҏ�� / notifyObservers(Object data)�Ҏ��
1 /**
2  * If {@code hasChanged()} returns {@code true}, calls the {@code update()}
3  * method for every observer in the list of observers using null as the
4  * argument. Afterwards, calls {@code clearChanged()}.
5  *

6  * Equivalent to calling {@code notifyObservers(null)}.
7  */
8 public void notifyObservers() {
9     notifyObservers(null);
10 }
11
12 /**
13  * If {@code hasChanged()} returns {@code true}, calls the {@code update()}
14  * method for every Observer in the list of observers using the specified
15  * argument. Afterwards calls {@code clearChanged()}.
16  *
17  * @param data
18  *            the argument passed to {@code update()}.
19  */
20 @SuppressWarnings("unchecked")
21 public void notifyObservers(Object data) {
22     int size = 0;
23     Observer[] arrays = null;
24     synchronized (this) {
25         if (hasChanged()) {
26             clearChanged();
27             size = observers.size();
28             arrays = new Observer[size];
29             observers.toArray(arrays);
30         }
31     }
32     if (arrays != null) {
33         for (Observer observer : arrays) {
34             observer.update(this, data);
35         }
36     }
37 }

以上两个�Ҏ��十分重要
setChanged()�Ҏ�� —�?
用来讄��一个内部标志位注明数据发生了变�?/span>
notifyObservers()�Ҏ�� / notifyObservers(Object data)�Ҏ�� —�?
通知所有的Observer数据发生了变化，�q�时所有的Observer会自动调用复写好�?span style="font-family:Arial; font-size:14px; color:#333333; line-height:21px">update(Observable observable, Object data)�Ҏ��来做一些处理（比如说画面数据的更新�Q��?/span>
我们可以看到通知Observer有两个方法，一个无参，一个有参。那么这个参数有什么作用呢�Q?/span>
其中一个作用：现在我不想通知所有的Observer�Q�而只惛_��中一个指定的Observer做一些处理，那么��可以传一个参��C��为ID�Q�然后在所有的Observer中判断，每个Observer判断只有接收到底参数ID是属于自��q��才做一些处理�?/span>
当然参数�q�有其他作用�Q�我只是举了个例子�?/span>

下面举个例子加以说明�Q?br />
1 import java.util.Observable;
2 /**
3  * 被观察者类
4  */
5 public class SimpleObservable extends Observable
6 {
7    private int data = 0;
8
9    public int getData(){
10        return data;
11    }
12
13    public void setData(int i){
14        if(this.data != i) {
15           this.data = i;
16           setChanged();
17
18           //只有在setChange()被调用后�Q�notifyObservers()才会去调用update()�Q�否则什么都不干。 �?/span>
19           notifyObservers();
20        }
21    }
22 }

上面�q�个�c�L��一个被观察者类�Q�它�l�承了Observable�c�，表示�q�个�c�L��可以被观察的�?
然后在setData()�Ҏ��里面�Q�也��是数据改变的地方，来调用Observable�cȝ��setChanged()�Ҏ��和notifyObservers()�Ҏ��Q�表�C�数据已改变�q��知所有的Observer调用它们的update()�Ҏ��做一些处理�?/p>
注意�Q?span>只有在setChange()被调用后�Q�notifyObservers()才会去调用update()�Q�否则什么都不干�?/span>
1     /**
2      * 观察者类
3      */
4     public class SimpleObserver implements Observer
5     {
6        public SimpleObserver(SimpleObservable simpleObservable){
7           simpleObservable.addObserver(this );
8        }
9
10        public void update(Observable observable ,Object data){  // data��Z�Q意对象，用于传递参敊W��?/span>
11           System.out.println(“Data has changed to”�?/span>+ (SimpleObservable)observable.getData());
12        }
13     }

通过生成被观察者（SimpleObservable�c?/span>�Q�的实例�Q�来调用addObserver(this)�Ҏ��让观察者（SimpleObserver�c?/span>�Q�达到观察被观察者（SimpleObservable�c?/span>�Q�的目的�?
然后�q�要复写update()�Ҏ��Q�做数据改变后的一些处理�?/p>
下面可以写一个简单的��试�c�L��试一�?/p>
1 public class SimpleTest
2 {
3    public static void main(String[] args){
4       SimpleObservable doc = new SimpleObservable ();
5       SimpleObserver view = new SimpleObserver (doc);
6       doc.setData(1);
7       doc.setData(2);
8       doc.setData(2);
9       doc.setData(3);
10    }
11 }

�q�行�l�果如下
[plain]view plaincopy
Data has changed to 1
Data has changed to 2  //�W�二�ơsetData(2)时由于没有setChange�Q�所以update没被调用
Data has changed to 3

下面介绍一个Observable�cȝ��其他一些属性和�Ҏ��
属�?—�?br />

1     // observers是一个List�Q�保存着所有要通知的observer。     �?/span>
2     List<Observer> observers = new ArrayList<Observer>();
3     // changed是一个boolean型标志位�Q�标志着数据是否改变了。 �?/span>
4     boolean changed = false;

�Ҏ�� —�?span style="color:#ff0000">

1     // ��d��一个Observer到列表observers中 �?/span>
2     public void addObserver(Observer observer) {
3         if (observer == null) {
4             throw new NullPointerException();
5         }
6         synchronized (this) {
7             if (!observers.contains(observer))
8                 observers.add(observer);
9         }
10     }
11
12     // 从列表observers中删除一个observer
13
14     public synchronized void deleteObserver(Observer observer) {
15         observers.remove(observer);
16     }
17
18     // 清空列表observers
19     public synchronized void deleteObservers() {
20         observers.clear();
21     }
22
23     // �q�回列表observers中observer的个敊W��?/span>
24
25     public int countObservers() {
26         return observers.size();
27     }
28
29
30     // 重置数据改变标志位�ؓ未改变 �?/span>
31     protected void clearChanged() {
32     changed = false;
33     }
34
35     // ��数据改变标志位讄��为改变 �?/span>
36
37     protected void setChanged() {
38         changed = true;
39     }
40
41
42     // 判断标志位的值 �?/span>
43     public boolean hasChanged() {
44         return changed;
45     }
46
47     // 通知所有observer�Q�无参）
48     public void notifyObservers() {
49         notifyObservers(null);
50     }
51     // 通知所有observer�Q�有参）
52     @SuppressWarnings("unchecked")
53     public void notifyObservers(Object data) {
54         int size = 0;
55         Observer[] arrays = null;
56         synchronized (this) {
57             if (hasChanged()) {
58                 clearChanged();
59                 size = observers.size();
60                 arrays = new Observer[size];
61                 observers.toArray(arrays);
62             }
63         }
64         if (arrays != null) {
65             for (Observer observer : arrays) {
66                 observer.update(this, data);
67             }
68         }
69     }

注意�Q�在Observer对象销毁前一定要用deleteObserver��其从列表中删除�Q�也��是在onDestroy()�Ҏ��中调�?span style="font-family:Arial; font-size:14px; line-height:21px">deleteObserver()�Ҏ��?/span>
不然因�ؓ�q�存在对象引用的关系�Q�Observer对象不会被垃圾收集，造成内存泄漏�Q��ƈ且已�ȝ��Observer仍会被通知刎ͼ�有可能造成意料外的错误�Q�而且随着列表��来��大�Q�notifyObservers操作也会��来��慢�?/span>

下面2个工�E�是Observable与Observer的经典运�?是android实现的单指拖动放大图片的操作
两个例子�Q?/span>
http://download.csdn.net/detail/tianjf0514/4237628
http://download.csdn.net/download/tianjf0514/4237634

听风 2017-07-25 10:39 发表评论

java�U�程池的�U�类和应�?

听风 — Tue, 25 Jul 2017 02:35:00 GMT

转发�? http://blog.csdn.net/paul342/article/details/52442932

Java通过Executors提供四种�U�程池，分别为：
newCachedThreadPool创徏一个可�~�存�U�程池，如果�U�程池长度超�q�处理需要，可灵�z�d��收空闲线�E�，若无可回�Ӟ��则新建线�E��?br /> newFixedThreadPool 创徏一个定长线�E�池�Q�可控制�U�程最大�ƈ发数�Q�超出的�U�程会在队列中等待�?br /> newScheduledThreadPool 创徏一个定长线�E�池�Q�支持定时及周期性�Q务执行�?br /> newSingleThreadExecutor 创徏一个单�U�程化的�U�程池，它只会用唯一的工作线�E�来执行��d��Q�保证所有�Q务按照指定顺�?FIFO, LIFO, 优先�U?执行�?/p>

(1) newCachedThreadPool
创徏一个可�~�存�U�程池，如果�U�程池长度超�q�处理需要，可灵�z�d��收空闲线�E�，若无可回�Ӟ��则新建线�E�。示例代码如下：

1 package test;
2 import java.util.concurrent.ExecutorService;
3 import java.util.concurrent.Executors;
4 public class ThreadPoolExecutorTest {
5  public static void main(String[] args) {
6   ExecutorService cachedThreadPool = Executors.newCachedThreadPool();
7   for (int i = 0; i < 10; i++) {
8    final int index = i;
9    try {
10     Thread.sleep(index * 1000);
11    } catch (InterruptedException e) {
12     e.printStackTrace();
13    }
14    cachedThreadPool.execute(new Runnable() {
15     public void run() {
16      System.out.println(index);
17     }
18    });
19   }
20  }
21 }

�U�程池�ؓ无限大，当执行第二个��d��时第一个�Q务已�l�完成，会复用执行第一个�Q务的�U�程�Q�而不用每�ơ新建线�E��?/span>

(2) newFixedThreadPool
创徏一个定长线�E�池�Q�可控制�U�程最大�ƈ发数�Q�超出的�U�程会在队列中等待。示例代码如下：

1     package test;
2     import java.util.concurrent.ExecutorService;
3     import java.util.concurrent.Executors;
4     public class ThreadPoolExecutorTest {
5      public static void main(String[] args) {
6       ExecutorService fixedThreadPool = Executors.newFixedThreadPool(3);
7       for (int i = 0; i < 10; i++) {
8        final int index = i;
9        fixedThreadPool.execute(new Runnable() {
10         public void run() {
11          try {
12           System.out.println(index);
13           Thread.sleep(2000);
14          } catch (InterruptedException e) {
15           e.printStackTrace();
16          }
17         }
18        });
19       }
20      }
21     }

因�ؓ�U�程池大��ؓ3�Q�每个�Q务输出index后sleep 2�U�，所以每两秒打印3个数字�?br /> 定长�U�程池的大小最好根据系�l�资源进行设�|�。如Runtime.getRuntime().availableProcessors()

(3) newScheduledThreadPool
创徏一个定长线�E�池�Q�支持定时及周期性�Q务执行。�g�q�执行示例代码如下：

1     package test;
2     import java.util.concurrent.Executors;
3     import java.util.concurrent.ScheduledExecutorService;
4     import java.util.concurrent.TimeUnit;
5     public class ThreadPoolExecutorTest {
6      public static void main(String[] args) {
7       ScheduledExecutorService scheduledThreadPool = Executors.newScheduledThreadPool(5);
8       scheduledThreadPool.schedule(new Runnable() {
9        public void run() {
10         System.out.println("delay 3 seconds");
11        }
12       }, 3, TimeUnit.SECONDS);
13      }
14     }

表示延迟3�U�执行�?/p>
定期执行�C�Z��代码如下�Q?/p>
1     package test;
2     import java.util.concurrent.Executors;
3     import java.util.concurrent.ScheduledExecutorService;
4     import java.util.concurrent.TimeUnit;
5     public class ThreadPoolExecutorTest {
6      public static void main(String[] args) {
7       ScheduledExecutorService scheduledThreadPool = Executors.newScheduledThreadPool(5);
8       scheduledThreadPool.scheduleAtFixedRate(new Runnable() {
9        public void run() {
10         System.out.println("delay 1 seconds, and excute every 3 seconds");
11        }
12       }, 1, 3, TimeUnit.SECONDS);
13      }
14     }

表示延迟1�U�后�?�U�执行一�ơ�?/p>

(4) newSingleThreadExecutor
创徏一个单�U�程化的�U�程池，它只会用唯一的工作线�E�来执行��d��Q�保证所有�Q务按照指定顺�?FIFO, LIFO, 优先�U?执行。示例代码如下：

1 package test;
2 import java.util.concurrent.ExecutorService;
3 import java.util.concurrent.Executors;
4 public class ThreadPoolExecutorTest {
5  public static void main(String[] args) {
6   ExecutorService singleThreadExecutor = Executors.newSingleThreadExecutor();
7   for (int i = 0; i < 10; i++) {
8    final int index = i;
9    singleThreadExecutor.execute(new Runnable() {
10     public void run() {
11      try {
12       System.out.println(index);
13       Thread.sleep(2000);
14      } catch (InterruptedException e) {
15       e.printStackTrace();
16      }
17     }
18    });
19   }
20  }
21 }

�l�果依次输出�Q�相当于��序执行各个��d��?/p>
你可以��用JDK自带的监控工��h��监控我们创徏的线�E�数量，�q�行一个不�l�止的线�E�，创徏指定量的�U�程�Q�来观察�Q?br /> 工具目录�Q?strong style="font-weight:bold">C:\Program Files\Java\jdk1.6.0_06\bin\jconsole.exe
�q�行�E�序做稍微修改：

1     package test;
2     import java.util.concurrent.ExecutorService;
3     import java.util.concurrent.Executors;
4     public class ThreadPoolExecutorTest {
5      public static void main(String[] args) {
6       ExecutorService singleThreadExecutor = Executors.newCachedThreadPool();
7       for (int i = 0; i < 100; i++) {
8        final int index = i;
9        singleThreadExecutor.execute(new Runnable() {
10         public void run() {
11          try {
12           while(true) {
13            System.out.println(index);
14            Thread.sleep(10 * 1000);
15           }
16          } catch (InterruptedException e) {
17           e.printStackTrace();
18          }
19         }
20        });
21        try {
22         Thread.sleep(500);
23        } catch (InterruptedException e) {
24         e.printStackTrace();
25        }
26       }
27      }
28     }

效果如下�Q?/p>

选择我们�q�行的程序：

监控�q�行状�?/p>

听风 2017-07-25 10:35 发表评论

如何�~�写多线�E�Socket�E�序

听风 — Tue, 25 Jul 2017 02:30:00 GMT
转自 http://blog.csdn.net/ooppookid/article/details/51711323

1、如何编写多�U�程Socket�E�序
了解Socket看这里：Socket是什�?/a>
多线�E�Socket与单�U�程�c�M��Q�只是��用了多线�E�的方式来管理连接，�ȝ��E�负责接收连�?/font>�Q�在接到�q�接后变创徏新的�U�程�Q�每个线�E�负责与自己的客��L��q�行通信�?/p>
了解单线�E�Socket看这里：如何�~�写单多�U�程Socket�E�序
与单�U�程Socket例子相比来说�Q�服务端可以�?font color="#ff0000">多个客户�?/font>�q�行通信了，不过多线�E�频�J�的创徏与销毁便会带�?font color="#ff0000">很大的资源开销�Q�而系�l�的�|�络资源�{�都是有限的。因此一般会引入�U�程�?/font>�Q�可以在某种�E�度上重用线�E�，减少�U�程的创建和销毁的�ơ数�?font color="#ff0000">减少开销�?/p>
我们的代码也分�ؓ客户端和服务�?/font>两部分。服务端的代码中包含�?font color="#ff0000">使用和不使用�U�程�?/font>的两�U�方式�?/p>
服务端代�?/font>�Q?/p>
1 import java.io.BufferedReader;
2 import java.io.IOException;
3 import java.io.InputStreamReader;
4 import java.io.PrintWriter;
5 import java.net.ServerSocket;
6 import java.net.Socket;
7 import java.util.concurrent.ExecutorService;
8 import java.util.concurrent.Executors;
9
10 public class SocketThreadPoolDemoServer {
11
12     private int port = 8000;
13
14     private ServerSocket serverSocket;
15
16     private ExecutorService executorService; // �q�接�?/span>
17
18     private final int POOL_SIZE = 1; // �q�接池大��? 若�ؓ 1 时最多支持�? �U�程
19
20     public SocketThreadPoolDemoServer() throws Exception {
21         serverSocket = new ServerSocket(port);
22         executorService = Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors() * POOL_SIZE);// 初始化线�E�池
23         System.out.println("waitting connet");
24
25     }
26
27     /**
28      *
29      * 接受�q�接
30      *
31      * @author sunjie at 2016�q?�?4�?br />32      *
33      */
34     public void service() {
35         Socket socket = null;
36         while (true) {
37             try {
38                 socket = serverSocket.accept();
39                 executorService.execute(new Handler(socket)); // 使用�q�接�?br />40                 // new Thread(new Handler(socket)).start();// 不��用连接池
41             } catch (IOException e) {
42                 e.printStackTrace();
43             }
44         }
45     }
46
47     /**
48      *
49      * �U�程�c�，负责�l�持与一个客��L��的通信
50      *
51      * @author sunjie at 2016�q?�?4�?br />52      *
53      */
54     class Handler implements Runnable {
55
56         private Socket socket = null;
57
58         public Handler(Socket socket) {
59             this.socket = socket;
60         }
61
62         @Override
63         public void run() {
64             System.out.println("new connection accepted:" + socket.getInetAddress() + ":" + socket.getPort());
65             try {
66                 BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream(), "UTF-8"));
67                 PrintWriter writer = new PrintWriter(socket.getOutputStream());
68                 String msg = null;
69                 while ((msg = reader.readLine()) != null) {
70                     System.out.println("from " + socket.getInetAddress() + ":" + socket.getPort() + ", receive msg:"
71                             + msg);
72                     writer.println(msg);
73                     writer.flush();
74                     if ("close".equals(msg)) {
75                         break;
76                     }
77                 }
78             } catch (IOException e) {
79                 e.printStackTrace();
80             } finally {
81                 try {
82                     if (socket != null) {
83                         socket.close();
84                     }
85                 } catch (IOException e) {
86                     e.printStackTrace();
87                 }
88             }
89         }
90     }
91
92     public static void main(String[] args) throws Exception {
93         new SocketThreadPoolDemoServer().service();
94     }
95 }
96
97

�q�行服务端代码后�Q�程序会一直进行监�?/font>�Q�直到接收到客户端请求�ؓ止。结果如下：
waitting connet�?/p>
客户端代�?/font>�Q�与单线�E�完全相同）�Q?/p>
1 public class SocketDemoClient { 2 3     private String host = "127.0.0.1";// 要发送给服务端的ip 4 5     private int port = 8000;// 要发送给服务端的端口 6 7     private Socket socket; 8 9     public SocketDemoClient() throws Exception { 10         socket = new Socket(host, port);// 构造Socket客户端，�q�与�q�接服务�?/span> 11     } 12 13     public void talk() throws IOException { 14         try { 15             BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream(), "UTF-8")); 16             PrintWriter writer = new PrintWriter(socket.getOutputStream()); 17             // ��d��本地控制台的消息 18             BufferedReader localReader = new BufferedReader(new InputStreamReader(System.in)); 19             String msg = null; 20             while ((msg = localReader.readLine()) != null) { 21                 writer.println(msg); 22                 writer.flush(); 23                 System.out.println("send msg:" + reader.readLine()); 24                 if ("close".equals(msg)) { 25                     break; 26                 } 27             } 28         } catch (Exception e) { 29             e.printStackTrace(); 30         } finally { 31             if (socket != null) { 32                 socket.close(); 33             } 34         } 35     } 36 37     public static void main(String[] args) throws Exception { 38         new SocketDemoClient().talk(); 39     } 40 }
�׃��我们�?a class="replace_word" title="软�g��试知识�? target="_blank" style="color:#df3434; font-weight:bold;">��试多个客户端连接同一个服务端�Q�所以我们需�?font color="#ff0000">多次�q�行客户端代�?/font>。这里我们运行两�ơ之后（�U�Cؓ客户�?、客��L��2�Q�，查看服务端的Console�Q�会出现以下�l�果�Q�说明已�l�连接成功：
waitting connet�?
new connection accepted:/127.0.0.1:59593
new connection accepted:/127.0.0.1:59596
我们在去客户�?的Console中输入我们要发送的消息”维护世界和�q�”，回�R��定后，客户�?的Console出现以下�l�果�Q�消息已�l�发出：
send msg:�l�护世界和��^
再去客户�?的Console中输入”好好学习天天向上”，回�R��定后，客户�?的Console出现以下�l�果�Q�消息已�l�发出：
send msg:好好学习天天向上
在服务端的Console中，我们会看到如下结果，说明两个客户端的消息已经被接�?/font>�Q?/p>
waitting connet�?
new connection accepted:/127.0.0.1:59593
new connection accepted:/127.0.0.1:59596
from /127.0.0.1:59593, receive msg:�l�护世界和��^
from /127.0.0.1:59596, receive msg:好好学习天天向上

听风 2017-07-25 10:30 发表评论

Android 实现PPPoE拨号

听风 — Thu, 08 Jun 2017 13:19:00 GMT
http://blog.csdn.net/wqx_163/article/details/50704252

听风 2017-06-08 21:19 发表评论

Android shell命��o查询ip�Q�网养I��DNS

听风 — Thu, 08 Jun 2017 13:18:00 GMT
http://www.cnblogs.com/mypsq/p/5821953.html

听风 2017-06-08 21:18 发表评论