Software Learning

安裝： brew install mysql 啟動：brew services start mysql 設定：mysql_secure_installation 停止：brew services stop mysql 登入： mysql -u <username> -p

定義物件 class Pair implements Comparable<Pair> { /* 自定義 object implements Comparable 42.07% */ int n ; int f ; public Pair ( int n , int f) { this . n = n ; this . f = f ; } public int compareTo (Pair o) { if ( this . f == o. f ) return o. n - this . n ; // desc return this . f - o. f ; // aces } }  之後排序可以使用 Collections. sort (l) ; 其中  List<Pair> l = new ArrayList<>() ;

Arrays. sort (pairs , (a , b) -> { if (a[ 0 ] == b[ 0 ]) return a[ 1 ] - b[ 1 ] ; // if same strength, row aces else return a[ 0 ] - b[ 0 ] ; // normal, strength aces }) ;

 在java string 中如火想要正確的split 句號(.) 必須要使用 String.split("\\.") example: "leetcode.com".split("\\.");

使用sdkman安裝多個不同版本的java 1. 安裝sdkman curl -s "https://get.sdkman.io" | bash 2. 顯示可安裝的java 版本 sdk  list java 3. 依照版本安裝 4. 切換java版本 5. java -version

  1. In Eclipse, stop Tomcat 2. Right-click your project and select Export > WAR File 3. In the Destination field, enter: <any-directory>/mycoolapp.war 4. Outside of Eclipse, start Tomcat - If you are using MS Windows, then you should find it on the Start menu 5. Make sure Tomcat is up and running by visiting: http://localhost:8080 6. Deploy your new WAR file by copying it to <tomcat-install-directory>\webapps Give it about 10-15 seconds to make the deployment. You'll know the deployment is over because you'll see a new folder created in webapps ... with your WAR file name. 7. Visit your new app. If your war file was: mycoolapp.war then you can access it with:  http://localhost:8080/mycoolapp/