Describes the configuration for an [Element].

Widgets are the central class hierarchy in the Flutter framework. A widget
is an immutable description of part of a user interface. Widgets can be
inflated into elements, which manage the underlying render tree.

Widgets themselves have no mutable state (all their fields must be final).
If you wish to associate mutable state with a widget, consider using a
[StatefulWidget], which creates a [State] object (via
[StatefulWidget.createState]) whenever it is inflated into an element and
incorporated into the tree.

A given widget can be included in the tree zero or more times. In particular
a given widget can be placed in the tree multiple times. Each time a widget
is placed in the tree, it is inflated into an [Element], which means a
widget that is incorporated into the tree multiple times will be inflated
multiple times.

The [key] property controls how one widget replaces another widget in the
tree. If the [runtimeType] and [key] properties of the two widgets are
[operator==], respectively, then the new widget replaces the old widget by
updating the underlying element (i.e., by calling [Element.update] with the
new widget). Otherwise, the old element is removed from the tree, the new
widget is inflated into an element, and the new element is inserted into the
tree.

See also:

 * [StatefulWidget] and [State], for widgets that can build differently
   several times over their lifetime.
 * [InheritedWidget], for widgets that introduce ambient state that can
   be read by descendant widgets.
 * [StatelessWidget], for widgets that always build the same way given a
   particular configuration and ambient state.

好的，我已经翻译了您的英文段落。请看下面的汉语版本。😊

Okay, I have translated your English paragraph. Please see the Chinese version below. 😊

/// 描述了[Element]的配置。
///
/// Widgets是Flutter框架中的核心类层次结构。一个widget是用户界面部分的不可变描述。Widgets可以被扩展成elements，它们管理底层的渲染树。
///
/// Widgets本身没有可变状态（它们的所有字段都必须是final）。如果您想要将可变状态与widget关联起来，请考虑使用[StatefulWidget]，它在每次被扩展成element并加入到树中时，都会创建一个[State]对象（通过[StatefulWidget.createState]）。
///
/// 一个给定的widget可以被包含在树中零次或多次。特别地，一个给定的widget可以被放置在树中多次。每次一个widget被放置在树中时，它都会被扩展成一个[Element]，这意味着一个被加入到树中多次的widget将会被扩展多次。
///
/// [key]属性控制了一个widget如何替换树中的另一个widget。如果两个widget的[runtimeType]和[key]属性分别是[operator==]，那么新的widget就会通过更新底层的element（即通过调用[Element.update]并传入新的widget）来替换旧的widget。否则，旧的element就会从树中移除，新的widget就会被扩展成一个element，并且新的element就会插入到树中。
///
/// 另请参阅：
///
///  * [StatefulWidget]和[State]，用于可以在其生命周期内以不同方式构建多次的widgets。
///  * [InheritedWidget]，用于引入可以被后代widgets读取的环境状态。
///  * [StatelessWidget]，用于始终以相同方式构建（给定特定配置和环境状态）的widgets。

Source: Conversation with Bing, 2/27/2023(1) . https://bing.com/search?q=translate+to+Chinese Accessed 2/27/2023.
(2) Google Translate. https://translate.google.com/;) Accessed 2/27/2023.
(3) Google 翻譯. https://translate.google.com/?hl=zh-TW Accessed 2/27/2023.
(4) DeepL Translate: The world's most accurate translator. https://www.deepl.com/en/translator-mobile Accessed 2/27/2023.

String uri = "http://10.12.29.138:8080/IMG_5899.png";
    String extension = uri.substring(uri.lastIndexOf(".") + 1);
    File savedFile = new File("/Users/admin/Downloads/123." + extension);
    FileUtils.copyURLToFile(new URL(uri), savedFile);

    Metadata metadata = ImageMetadataReader.readMetadata(savedFile);
    // See whether it has GPS data
    Collection<GpsDirectory> gpsDirectories = metadata.getDirectoriesOfType(GpsDirectory.class);
    for (GpsDirectory gpsDirectory : gpsDirectories) {
        // Try to read out the location, making sure it's non-zero
        GeoLocation geoLocation = gpsDirectory.getGeoLocation();
        if (geoLocation != null && !geoLocation.isZero()) {
            System.out.println(geoLocation.getLatitude());
            System.out.println(geoLocation.getLongitude());
        }
    }
}

docker pull nginx

docker pull vsftpd

cat default.conf
server {
    listen       80;
    listen  [::]:80;
    server_name  localhost;

    #access_log  /var/log/nginx/host.access.log  main;

    location / {
        root   /mnt/data;
        index  index.html index.htm;
    }

    #error_page  404              /404.html;

    # redirect server error pages to the static page /50x.html
    #
    error_page   500 502 503 504  /50x.html;
    location = /50x.html {
        root   /usr/share/nginx/html;
    }

    # proxy the PHP scripts to Apache listening on 127.0.0.1:80
    #
    #location ~ \.php$ {
    #    proxy_pass   http://127.0.0.1;
    #}

    # pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
    #
    #location ~ \.php$ {
    #    root           html;
    #    fastcgi_pass   127.0.0.1:9000;
    #    fastcgi_index  index.php;
    #    fastcgi_param  SCRIPT_FILENAME  /scripts$fastcgi_script_name;
    #    include        fastcgi_params;
    #}

    # deny access to .htaccess files, if Apache's document root
    # concurs with nginx's one
    #
    #location ~ /\.ht {
    #    deny  all;
    #}
}

cat nginx.conf

user root;
worker_processes  auto;

error_log  /var/log/nginx/error.log notice;
pid        /var/run/nginx.pid;


events {
    worker_connections  1024;
}


http {
    include       /etc/nginx/mime.types;
    default_type  application/octet-stream;

    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';

    access_log  /var/log/nginx/access.log  main;

    sendfile        on;
    #tcp_nopush     on;

    keepalive_timeout  65;

    #gzip  on;

    include /etc/nginx/conf.d/*.conf;
}

docker run -d -p 80:80 \
--name nginx --net host \
-v /usr/docker/nginx/nginx.conf:/etc/nginx/nginx.conf \
-v /usr/docker/nginx/conf.d/default.conf:/etc/nginx/conf.d/default.conf \
-v /usr/docker/nginx/html:/usr/share/nginx/html \
-v /usr/docker/vsftpd:/mnt/data \
-v /usr/docker/nginx/logs:/var/log/nginx \
--privileged=true --restart=always nginx

docker run -d -v /root/docker/vsftpd:/home/vsftpd \
-p 20:20 -p 21:21 -p  21100-21110:21100-21110 \
-e FTP_USER=test -e FTP_PASS=testgs \
-e PASV_ADDRESS=104.225.145.216 \
-e PASV_MIN_PORT=21100 -e PASV_MAX_PORT=21110 \
--name vsftpd --restart=always fauria/vsftpd

tags: [life，travel]  

tags:
- jQuery
- 表格
- 表单验证

//快捷打印
public static void print(Object o){
        System.out.println(o);
    }

\d 匹配数字 任意个数数字 

 print("a8738bkj2238c0918".replaceAll("\\d","_"));

输出 a____bkj____c____

Pattern类的使用
Pattern pattern = Pattern.compile("\\d");
Matcher matcher = pattern.matcher("abc");
print( matcher.matches());

true

. 匹配任何，任何的字符

*	匹配前面的子表达式零次或多次。例如，zo*能匹配“z”以及“zoo”。*等价于{0,}。

+	匹配前面的子表达式一次或多次。例如，“zo+”能匹配“zo”以及“zoo”，但不能匹配“z”。+等价于{1,}。

?	当该字符紧跟在任何一个其他限制符（*,+,?，{n}，{n,}，{n,m}）后面时，匹配模式是非贪婪的。非贪婪模式尽可能少的匹配所搜索的字符串，而默认的贪婪模式则尽可能多的匹配所搜索的字符串。例如，对于字符串“oooo”，“o+?”将匹配单个“o”，而“o+”将匹配所有“o”。

? 在正则表达式中元字符 ? 标记在符号前面的字符为可选，即出现 0 或 1 次。 例如，表达式 [T]?he 匹配字符串 he 和 The。

{}  限定一个或一组字符可以重复出现的次数。 例如， 表达式 [0-9]{2,3} 匹配最少 2 位最多 3 位 0~9 的数字。

[ ]	字符种类。匹配方括号内的任意字符。

\	转义字符,用于匹配一些保留的字符 [ ] ( ) { } . * + ? ^ $ \ |

\d	匹配数字： [0-9]

\s	匹配所有空格(空白)字符，等同于： [\t\n\f\r\p{Z}]

\w	匹配所有字母数字，等同于 [a-zA-Z0-9_]