js复制代码public class 类名 {
        public static final 类型  静态常量名称  = 静态常量值;
}

js复制代码public class Constants {
    /**
     *  稀土
     */
    public static final String  XITU  = "稀土";

    /**
     *  掘金
     */
    public static final String  JUEJIN  = "掘金";

    /**
     * 代码不止
     */
    public static final String  DAIMABUZHI  = "代码不止";

    /**
     *  掘金不停
     */
    public static final String  JUEJINBUTING  = "掘金不停";

    /**
     *  掘金网站
     */
    public static final String  JUEJIN_URL  = "https://juejin.cn/";

js复制代码  public static void main(String[] args) {
            System.out.println(Constants.XITU+Constants.JUEJIN+Constants.DAIMABUZHI+Constants.JUEJINBUTING+Constants.JUEJIN_URL);
    }

js复制代码public interface 接口对象的名称 {

    /**
     * 常量的名称
     */
    类型  常量的名称 = 常量值;

}

js复制代码public interface InterfaceinConstants {

    /**
     * JUEJIN_QUEUE
     */
    String JUEJIN_QUEUE = "JUEJIN_KEY";

    /**
     * JUEJIN_KEY
     */
    String JUEJIN_KEY = "JUEJIN_KEY";

    /**
     * JUEJIN_EXCHANGE
     */
    String JUEJIN_EXCHANGE = "JUEJIN_EXCHANGE";
}

js复制代码 public static void main(String[] args) {
        System.out.println(Constants.XITU+Constants.JUEJIN+Constants.DAIMABUZHI+Constants.JUEJINBUTING+Constants.JUEJIN_URL);
        System.out.println(InterfaceinConstants.JUEJIN_EXCHANGE+InterfaceinConstants.JUEJIN_KEY+InterfaceinConstants.JUEJIN_QUEUE);
    }

js复制代码public enum 枚举名称 {
    属性名称(值1,值2，值3...值N)
    ;
}

js复制代码public enum PushStateEnum {
    PUSH_NO(0,"未推送"),
    PUSH_FAIL(1,"失败"),
    PUSH_YES(2,"成功")
    ;

    private Integer code;

    @JsonValue
    private String desc;

    public static String getDescByValue(int value){
        for (PushStateEnum item : PushStateEnum.values()) {
            if(item.getCode()==value){
                return item.getDesc();
            }
        }
        return null ;
    }

    public static PushStateEnum getEnum(int value){
        for (PushStateEnum item : PushStateEnum.values()) {
            if(item.getCode()==value){
                return item ;
            }
        }
        return null ;
    }
}

js复制代码 public static void main(String[] args) {
        System.out.println(PushStateEnum.PUSH_NO.getDesc());
        System.out.println(PushStateEnum.PUSH_NO.getCode());
        System.out.println(PushStateEnum.PUSH_FAIL.getDesc());
        System.out.println(PushStateEnum.PUSH_FAIL.getCode());
        System.out.println(PushStateEnum.PUSH_YES.getDesc());
        System.out.println(PushStateEnum.PUSH_YES.getCode());
    }

java复制代码2021-11-06 23:56:52.095  INFO 2112 --- [ntContainer#0-1] c.l.m.c.listener.SpringRabbitListener    : 正常业务交换机 | 接收到的消息 : [hello]
2021-11-06 23:56:52.118  INFO 2112 --- [ntContainer#1-1] c.l.m.c.listener.SpringRabbitListener    : 死信交换机 | 接收到的消息 : hello

java复制代码2021-11-07 00:01:30.854  INFO 32752 --- [ntContainer#1-1] c.l.m.c.listener.SpringRabbitListener    : 死信交换机 | 接收到的消息 : test ttl-message

java复制代码2021-11-07 00:03:09.048  INFO 39996 --- [ntContainer#1-1] c.l.m.c.listener.SpringRabbitListener    : 死信交换机 | 接收到的消息 : this is a ttl message

shell复制代码docker run -itd --name rabbitmq -v plugins:/plugins -p 15672:15672 -p 5672:5672 rabbitmq:management

shell复制代码rabbitmq-plugins enable rabbitmq_delayed_message_exchange

shell复制代码rabbitmqctl set_policy Lazy "^lazy-queue$" '{"queue-mode":"lazy"}' --apply-to queues

kotlin复制代码# MainViewModel
class MainViewModel {
    private val _userLiveData = MutableStateLiveData<User?>()
    val userLiveData : StateLiveData<User?> = _userLiveData
    fun login(username: String, password: String) {
        viewModelScope.launch {
            _userLiveData.value = repository.login(username, password)
        }
    }
}

class MainActivity : AppCompatActivity() {
    fun initViewModel(){
	// 请求网络
	mViewModel.login("username", "password")
	// 注册监听
	mViewModel.userLiveData.observeState(this) {
            onLoading {
		showLoading()
            }
            onSuccess {data ->
		mBinding.tvContent.text = data.toString()
            }
            onError {
                dismissLoading()
            }
	}
    }
}

kotlin复制代码class NetworkViewModel : ViewModel() {
    /**
     * 页面请求，通常包括刷新页面loading状态等
     */
    private fun pageRequest() {
        viewModelScope.rxLaunch<String> {
            onRequest = {
                _viewStates.setState { copy(pageStatus = PageStatus.Loading) }
                delay(2000)
                "页面请求成功"
            }
            onSuccess = {
                _viewStates.setState { copy(content = it, pageStatus = PageStatus.Success) }
                _viewEvents.setEvent(NetworkViewEvent.ShowToast("请求成功"))
            }
            onError = {
                _viewStates.setState { copy(pageStatus = PageStatus.Error(it)) }
            }
        }
    }
}

# Activity层
class MainActivity : AppCompatActivity() {
    private fun initViewModel() {
        viewModel.viewStates.let { state ->
            //监听网络请求状态
            state.observeState(this, NetworkViewState::pageStatus) {
                when (it) {
                    is PageStatus.Success -> state_layout.showContent()
                    is PageStatus.Loading -> state_layout.showLoading()
                    is PageStatus.Error -> state_layout.showError()
                }
            }
            //监听页面数据
            state.observeState(this, NetworkViewState::content) {
                tv_content.text = it
            }
        }
        //监听一次性事件，如Toast,ShowDialog等   
        viewModel.viewEvents.observe(this) {
            when (it) {
                is NetworkViewEvent.ShowToast -> toast(it.message)
                is NetworkViewEvent.ShowLoadingDialog -> showLoadingDialog()
                is NetworkViewEvent.DismissLoadingDialog -> dismissLoadingDialog()
            }
        }
    }
}

kotlin复制代码    /**
     * 页面局部请求，例如点赞收藏等，通常需要弹dialog或toast
     */
    private fun partRequest() {
        viewModelScope.rxLaunch<String> {
            onRequest = {
                _viewEvents.setEvent(NetworkViewEvent.ShowLoadingDialog)
                delay(2000)
                "点赞成功"
            }
            onSuccess = {
                _viewEvents.setEvent(NetworkViewEvent.DismissLoadingDialog)
                _viewEvents.setEvent(NetworkViewEvent.ShowToast(it))
                _viewStates.setState { copy(content = it) }
            }
            onError = {
                _viewEvents.setEvent(NetworkViewEvent.DismissLoadingDialog)
            }
        }
    }

kotlin复制代码    /**
     * 多数据源请求
     */
    private fun multiSourceRequest() {
        viewModelScope.rxLaunch<String> {
            onRequest = {
                _viewEvents.setEvent(NetworkViewEvent.ShowLoadingDialog)
                coroutineScope {
                    val source1 = async { source1() }
                    val source2 = async { source2() }
                    val result = source1.await() + "," + source2.await()
                    result
                }
            }
            onSuccess = {
                _viewEvents.setEvent(NetworkViewEvent.DismissLoadingDialog)
                _viewEvents.setEvent(NetworkViewEvent.ShowToast(it))
                _viewStates.setState { copy(content = it) }
            }
            onError = {
                _viewEvents.setEvent(NetworkViewEvent.DismissLoadingDialog)
            }
        }
    }

kotlin复制代码class CoroutineScopeHelper<T>(private val coroutineScope: CoroutineScope) {
    fun rxLaunch(init: LaunchBuilder<T>.() -> Unit): Job {
        val result = LaunchBuilder<T>().apply(init)
        val handler = NetworkExceptionHandler {
            result.onError?.invoke(it)
        }
        return coroutineScope.launch(handler) {
            val res: T = result.onRequest()
            result.onSuccess?.invoke(res)
        }
    }
}

kotlin复制代码    /**
     * 页面请求，通常包括刷新页面loading状态等
     */
    private fun pageRequest() {
        viewModelScope.launch {
            flow {
                delay(2000)
                emit("页面请求成功")
            }.onStart {
                _viewStates.setState { copy(pageStatus = PageStatus.Loading) }
            }.onEach {
                _viewStates.setState { copy(content = it, pageStatus = PageStatus.Success) }
                _viewEvents.setEvent(NetworkViewEvent.ShowToast(it))
            }.commonCatch {
                _viewStates.setState { copy(pageStatus = PageStatus.Error(it)) }
            }.collect()
        }
    }

kotlin复制代码    /**
     * 多数据源请求
     */
    private fun multiSourceRequest() {
        viewModelScope.launch {
            val flow1 = flow {
                delay(1000)
                emit("数据源1")
            }
            val flow2 = flow {
                delay(2000)
                emit("数据源2")
            }
            flow1.zip(flow2) { a, b ->
                "$a,$b"
            }.onStart {
                _viewEvents.setEvent(NetworkViewEvent.ShowLoadingDialog)
            }.onEach {
                _viewEvents.setEvent(NetworkViewEvent.DismissLoadingDialog)
                _viewEvents.setEvent(NetworkViewEvent.ShowToast(it))
                _viewStates.setState { copy(content = it) }
            }.commonCatch {
                _viewEvents.setEvent(NetworkViewEvent.DismissLoadingDialog)
            }.collect()
        }
    }

kotlin复制代码fun <T> Flow<T>.commonCatch(action: suspend FlowCollector<T>.(cause: Throwable) -> Unit): Flow<T> {
    return this.catch {
        if (it is UnknownHostException || it is SocketTimeoutException) {
            MyApp.get().toast("发生网络错误，请稍后重试")
        } else {
            MyApp.get().toast("请求失败，请重试")
        }
        action(it)
    }
}

kotlin复制代码    private fun fetchNews() {
        viewModelScope.launch {
            flow {
                emit(repository.getMockApiResponse())
            }.onStart {
                _viewStates.setState { copy(fetchStatus = FetchStatus.Fetching) }
            }.onEach {
                _viewStates.setState { copy(fetchStatus = FetchStatus.Fetched, newsList = it.data)}
            }.commonCatch {
                _viewStates.setState { copy(fetchStatus = FetchStatus.Fetched) }
            }.collect()
        }
    }

python复制代码import zoneinfo

python复制代码import zoneinfo
from datetime import  datetime,timedelta,timezone

tz = zoneinfo.ZoneInfo("Pacific/Kwajalein")

date_utc = datetime(2021,11,7,20,tzinfo=timezone.utc)

date_tz = date_utc.astimezone(tz)

date_tz_dst = date_tz+timedelta(hours=1)

print("utc时间：",date_utc)
print("tz时间：",date_tz)
print("tz_dst时间：",date_tz_dst)
print("时区简称：",date_utc.tzname())

csharp复制代码from flask import Flask


def create_app():
    app = Flask(__name__)
    # 加载配置

    # 注册蓝本

    # 初始化扩展

    return app

python复制代码from factory import create_app

app = create_app()

@app.route('/')
def hello_world():
    return 'Hello World!'


if __name__ == '__main__':
    app.run()

ruby复制代码# @FileName: settings
class BaseConfig(object):
    # 基础配置

class DevelopmentConfig(BaseConfig):
    # 开发环境配置

class TestConfig(BaseConfig):
    # 测试环境配置

class ProductionConfig(BaseConfig):
    # 生产环境(上线环境)配置

csharp复制代码//factory.py
from flask import Flask
import settings


def create_app():
    app = Flask(__name__)
    # 加载配置
    app.config.from_object(settings.DevelopmentConfig)
    # 注册蓝图

    # 初始化扩展

    return app

ini复制代码# @FileName: extendsions
from flask_sqlalchemy import SQLAlchemy

#扩展类实例化
db = SQLAlchemy()
#......

python复制代码# @FileName: __init__.py

from flask import  Blueprint
#从Flask导入Blueprint类，实例化这个类就获得了我们的蓝本对象。
user_bp = Blueprint("user",__name__)
#构造方法中的第一个参数是蓝本的名称；第二个参数是包或模块的名称，我们可以使用__name__变量
from . import login 
#导入需要使用蓝图的视图文件，在下面导入解决循环导入报错

python复制代码//blueprints/user/login.py
from bluprints.user import user_bp


@user_bp.route('/')
def test():
    return "hello bluprint"

ini复制代码from pymongo import MongoClient
import redis
MONGODB_HOST = "106.14.107.75"
MONGODB_PORT = 27017
MONGODB_DATABASE = "mymongo"
REDIS_HOST = "106.14.107.75"
REDIS_PORT = 6379
REDIS_AUTH = "123456"

#mongodb            获取指定集合对象
def mongodbConnection(collectionName):
    myclient = MongoClient(MONGODB_HOST, MONGODB_PORT)
    mydb = myclient[MONGODB_DATABASE]
    collection = mydb[collectionName]
    return collection

#redis              获取指定数据库(0~15)连接对象
def redisConnection(databaseNum):
    pool = redis.ConnectionPool(host=REDIS_HOST, port=REDIS_PORT, password=REDIS_AUTH, db=databaseNum, decode_responses=True)
    mycon = redis.Redis(connection_pool=pool)
    return mycon

ini复制代码collection = mongodbConnection("address")
#获得mongodb address集合操作对象
con = redisConnection(0)
#获得redis  0号数据库操作对象

ini复制代码# @FileName: models
from extendsions import db


class User(db.Model):
    __tablename__ = "user_flask"
    id = db.Column(db.Integer,primary_key=True)
    name = db.Column(db.String(20))
    age = db.Column(db.Integer)
    sex = db.Column(db.String(2))
    love = db.Column(db.String(20))
    
#.......

java复制代码示例 1：

输入：nums = [1,2,3,4]
输出：3
解释：nums 中有三个子等差数组：[1, 2, 3]、[2, 3, 4] 和 [1,2,3,4] 自身。

java复制代码示例 2：

输入：nums = [1]
输出：0

java复制代码class Solution {
    public int numberOfArithmeticSlices(int[] nums) {
        int n = nums.length;
        if (n == 1) {
            return 0;
        }

        int d = nums[0] - nums[1], t = 0;
        int ans = 0;
        // 因为等差数列的长度至少为 3，所以可以从 i=2 开始枚举
        for (int i = 2; i < n; ++i) {
            if (nums[i - 1] - nums[i] == d) {
                ++t;
            } else {
                d = nums[i - 1] - nums[i];
                t = 0;
            }
            ans += t;
        }
        return ans;
    }
}

java复制代码示例 1：

输入：s = "12"
输出：2
解释：它可以解码为 "AB"（1 2）或者 "L"（12）。

java复制代码示例 2：

输入：s = "226"
输出：3
解释：它可以解码为 "BZ" (2 26), "VF" (22 6), 或者 "BBF" (2 2 6) 。

java复制代码示例 3：

输入：s = "0"
输出：0
解释：没有字符映射到以 0 开头的数字。
含有 0 的有效映射是 'J' -> "10" 和 'T'-> "20" 。
由于没有字符，因此没有有效的方法对此进行解码，因为所有数字都需要映射。

java复制代码示例 4：

输入：s = "06"
输出：0
解释："06" 不能映射到 "F" ，因为字符串含有前导 0（"6" 和 "06" 在映射中并不等价）。

java复制代码class Solution {
    public int numDecodings(String s) {
        int n = s.length();
        int[] f = new int[n + 1];
        f[0] = 1;
        for (int i = 1; i <= n; ++i) {
            if (s.charAt(i - 1) != '0') {
                f[i] += f[i - 1];
            }
            if (i > 1 && s.charAt(i - 2) != '0' && ((s.charAt(i - 2) - '0') * 10 + (s.charAt(i - 1) - '0') <= 26)) {
                f[i] += f[i - 2];
            }
        }
        return f[n];
    }
}

作者：LeetCode-Solution
链接：https://leetcode-cn.com/problems/decode-ways/solution/jie-ma-fang-fa-by-leetcode-solution-p8np/
来源：力扣（LeetCode）
著作权归作者所有。商业转载请联系作者获得授权，非商业转载请注明出处。

java复制代码七、系统和关机 (系统的关机、重启以及登出 )
shutdown -h now 关闭系统(1)
init 0 关闭系统(2)
telinit 0 关闭系统(3)
shutdown -h hours:minutes & 按预定时间关闭系统
shutdown -c 取消按预定时间关闭系统
shutdown -r now 重启(1)
reboot 重启(2)
logout 注销
time 测算一个命令（即程序）的执行时间

shell复制代码$ docker pull redis:4
$ docker exec -p 6379:6379 -itd --name redis redis:4
# 进入容器
$ docker exec -it redis sh

shell复制代码$ redis-cli
redis-cli(6379)> set name foo
OK
redis-cli(6379)> get name
"foo"

shell复制代码$ redis-server /config/redis/redis.conf -p 400

c复制代码// server.c
/* Global vars */
struct redisServer server; /* Server global state */

c复制代码int aeCreateFileEvent(aeEventLoop *eventLoop, int fd, int mask,
        aeFileProc *proc, void *clientData)

c复制代码void aeMain(aeEventLoop *eventLoop) {
    eventLoop->stop = 0;
    while (!eventLoop->stop) {
        if (eventLoop->beforesleep != NULL)
            eventLoop->beforesleep(eventLoop);
        aeProcessEvents(eventLoop, AE_ALL_EVENTS|AE_CALL_AFTER_SLEEP);
    }
}

sql复制代码CREATE TABLE `test_table` (
  `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(1000) NOT NULL DEFAULT '',
  `link` varchar(1000) NOT NULL DEFAULT '',
  PRIMARY KEY (`id`),
  KEY `name` (`name`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8mb4;

sql复制代码set global innodb_large_prefix=on;
set global innodb_file_per_table=on;
set global innodb_file_format=BARRACUDA;
set global innodb_file_format_max=BARRACUDA;

sql复制代码CREATE TABLE `test_table` (
  `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(255) NOT NULL DEFAULT '',
  `link` varchar(255) NOT NULL DEFAULT '',
  PRIMARY KEY (`id`),
  KEY `name` (`name`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 row_format=DYNAMIC;

css复制代码sh seata-server.sh -p 8091 -h 127.0.0.1 -m file

sql复制代码drop table if exists `global_table`;
create table `global_table` (
  `xid` varchar(128)  not null,
  `transaction_id` bigint,
  `status` tinyint not null,
  `application_id` varchar(32),
  `transaction_service_group` varchar(32),
  `transaction_name` varchar(128),
  `timeout` int,
  `begin_time` bigint,
  `application_data` varchar(2000),
  `gmt_create` datetime,
  `gmt_modified` datetime,
  primary key (`xid`),
  key `idx_gmt_modified_status` (`gmt_modified`, `status`),
  key `idx_transaction_id` (`transaction_id`)
);

-- the table to store BranchSession data
drop table if exists `branch_table`;
create table `branch_table` (
  `branch_id` bigint not null,
  `xid` varchar(128) not null,
  `transaction_id` bigint ,
  `resource_group_id` varchar(32),
  `resource_id` varchar(256) ,
  `lock_key` varchar(128) ,
  `branch_type` varchar(8) ,
  `status` tinyint,
  `client_id` varchar(64),
  `application_data` varchar(2000),
  `gmt_create` datetime,
  `gmt_modified` datetime,
  primary key (`branch_id`),
  key `idx_xid` (`xid`)
);

-- the table to store lock data
drop table if exists `lock_table`;
create table `lock_table` (
  `row_key` varchar(128) not null,
  `xid` varchar(96),
  `transaction_id` long ,
  `branch_id` long,
  `resource_id` varchar(256) ,
  `table_name` varchar(32) ,
  `pk` varchar(36) ,
  `gmt_create` datetime ,
  `gmt_modified` datetime,
  primary key(`row_key`)
);

conf复制代码 db {
    ## the implement of javax.sql.DataSource, such as DruidDataSource(druid)/BasicDataSource(dbcp)/HikariDataSource(hikari) etc.
    datasource = "dbcp"
    ## mysql/oracle/postgresql/h2/oceanbase etc.
    dbType = "mysql"
    driverClassName = "com.mysql.jdbc.Driver"
    ## if using mysql to store the data, recommend add rewriteBatchedStatements=true in jdbc connection param
    url = "jdbc:mysql://127.0.0.1:3306/seata?rewriteBatchedStatements=true"
    user = "mysql"
    password = "mysql"
    minConn = 5
    maxConn = 100
    globalTable = "global_table"
    branchTable = "branch_table"
    lockTable = "lock_table"
    queryLimit = 100
    maxWait = 5000
  }

sh复制代码seata-server.sh -h 127.0.0.1 -p 8091 -m db -n 1