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Helicopters and multiples

Jolied

Question on this code:

1. As far as I know, Servlet Container is responsible for the velocity of the shells.

2. But there is an option that, despite this, there may be a problem with stream security as in this code.

My question is: Why does this code make a variable counter count not to be insecure?

package threadSafety;
import java.io.IOException;
import javax.servlet.*;
import javax.servlet.http.*;
import java.math.*;
public class SimpleServlet extends HttpServlet
{
//A variable that is NOT thread-safe!
private int counter = 0;
public void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException
{
doPost(req, resp);
}
public void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException
{
resp.getWriter().println("<HTML><BODY>");
resp.getWriter().println(this + ": <br>");
for (int c = 0; c < 10; c++)
{
  resp.getWriter().println("Counter = " + counter + "<BR>");
  try
  {
    Thread.currentThread().sleep((long) Math.random() * 1000);
    counter++;
  }
  catch (InterruptedException exc) { }
}
resp.getWriter().println("</BODY></HTML>");
}
}

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tahishae last edited by

The creation of own fluxes in a silver container is not a good practice. If there's a way, you'd better go. https://docs.oracle.com/javaee/7/tutorial/servlets012.htm ♪
Otherwise, you yourself have to be responsible for the velocity, the disengagement, and over control of your flows.
Answering your questions:
1. As far as I know, Servlet Container is responsible for the velocity of the shells.
For the flows you've created, no.
2. But there is an option that, despite this, there may be a problem with stream security as in this code.
Because you have a variable level copy copy, and the container creates only one copy of his class for each silver. https://java.net/downloads/servlet-spec/Final/servlet-3_1-final.pdf - Chapter 2, paragraph 2.2.), then this variable will be common to all requests and may modify it accordingly by several requests simultaneously.
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call attributes through multiple relationships and select multiple
Software Programming • php jquery laravel 5 • • fbio

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I doubt it is the most efficient way, but if you have created the relationships in the models, you can try using the with() to bring the table related to their fields.InstanciasServidor::all()->with('instancias')->get() The ideal would be to use pivot tables (pivot tables), for which it would be good to see some short and simple tutorial (such as Styde for example).
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Returning Multiple Values
Software Programming • c language matrix logic language • • terrea

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In short, it is printing Não Encontrado!! :( several times why the condition is within a loop of repetition.First of all: arrays in C start in zero. What does that mean? Your matrix has 5 x 5 positions and you theoretically this using only 4 x 4 of them. You are using only the elements that have 1. Those who have 0 you are wasting.0 0 0 0 0 0 1 1 1 1 0 1 1 1 1 0 1 1 1 1 0 1 1 1 1 Then declare the matrix as follows to have 5 x 5 positions:int matriz[5][5] This way you have 5 position possibilities: 0,1,2,3,4. Your matrix is like this:1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Now for your problem. Note that in the passage://Você percorre CADA elemento da matriz for(i = 0; i < 5; i++){ for(j = 0; j < 5; j++){ //Se o elemento matriz[i][j] está na matriz, então imprima sua posição if(X == matriz[i][j]){ printf("\nEstá na linha: %d coluna: %d", i, j); //Se o elemento matriz[i][j] não está nessa matriz, imprima Não encontrado }else{ printf("\nNão Encontrado!! :("); } } } You make the comparison for each element. Soon, if the element matriz[i][j] is not equal to the value sought, you will print not found. As you pass element by element, the message is printed several times. To solve this some solutions are possible. One is: signal that the element was found:bool stop = false; //Percorra CADA elemento da matriz, se foi encontrado o elemento foi encontrado ou i < 5 você para. for(i = 0; i < 5 && !stop ; i++){ for(j = 0; j < 5 && !stop; j++){ //Se o elemento matriz[i][j] está na matriz, então imprima sua posição e pare os laços. if(X == matriz[i][j]){ printf("\nEstá na linha: %d coluna: %d", i, j); stop = true; } } } //Se o elemento não foi encontrado ( em nenhum momento passou para true ) if(!stop){ printf("\nNão Encontrado!! :("); }
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from python to java
Software Programming • java python • • emran

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♪ java 8 It could look like,import java.util.Scanner; public class Example { public static void main(String[] args) { int userNumber = getUserName() .chars() .filter(c -> c != ' ') .map(Character::toLowerCase) .map(c -> c - 92) .sum(); System.out.println(userNumber); } private static String getUserName() { System.out.println("Please enter your name, and I'll convert it to a number: "); Scanner scanner = new Scanner(System.in); String userName = scanner.next(); scanner.close(); return userName; } } If the older version is, the method. main may be replaced by:public static void main(String[] args) { int userNumber = 0; for (char character : getUserName().toCharArray()) { if (character != ' ') { userNumber += Character.toLowerCase(character) - 92; } } System.out.println(userNumber); }
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I want to update the graphics of JPanel from another class
Software Programming • java swing • • Cleofas

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First, you should not save the Graphics object passed by paintGraphonent(Graphics g), and you should not call it after you exit paint。onent(Graphics g). If you want to delegate drawing processing to other classes, you can use paint Graphiconent() to define a Graphics object to call the method:timer updates the Circle state (frame of animation) and calls repaint()Stop timer when Circle animation is finishedpaintGraphonent(Graphics g)Circle#GraphCircle(Graphics2D g2)Although it is different from expected behavior because it is large, the following shows the result that I tried to fix the original type as much as possible.FrameOf FramereadCircle.javaimport javax.swing.JFrame; public class FrameOfSpreadCircle { static SpreadCirclePanel panel = new SpreadCirclePanel(); public static void main(String args[]) { JFrame frame = new JFrame("SpreadCircle"); frame.addKeyListener(panel); frame.add(panel); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.pack(); frame.setVisible(true); } } SpreadCirclePanel.javaimport java.awt.Color; import java.awt.Dimension; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.RenderingHints; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.KeyEvent; import java.awt.event.KeyListener; import javax.swing.JPanel; import javax.swing.Timer; public class SpreadCirclePanel extends JPanel implements KeyListener, ActionListener { public static final int CIRCLE_SIZE = 50; private Circle circle; private final Timer timer; public SpreadCirclePanel() { super(); setPreferredSize(new Dimension(600, 400)); setBackground(Color.GRAY); timer = new Timer(60, this); } @Override public void keyTyped(KeyEvent e) { if (circle == null) { circle = new Circle(CIRCLE_SIZE); timer.start(); } } @Override public void paintComponent(Graphics g) { Graphics2D g2 = (Graphics2D) g; super.paintComponent(g2); // アンチエイリアスを有効に設定 g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); if (circle != null) { circle.drawCircle(g2); // 円を描画 } } @Override public void keyPressed(KeyEvent e) { } @Override public void keyReleased(KeyEvent e) { } public void actionPerformed(ActionEvent ae) { if (circle != null) { circle.updateCircle(); if (circle.isEnd()) { timer.stop(); circle = null; } repaint(); } } } Circleimport java.awt.Color; import java.awt.Graphics2D; public class Circle { int centerX, centerY; int l; int a; int b; int c; int alpha = 100; int time = 0; public Circle(int w) { l = w; centerX = (int) (Math.random() * 300); centerY = (int) (Math.random() * 200); a = (int) (Math.random() * 256); b = (int) (Math.random() * 256); c = (int) (Math.random() * 256); } public void updateCircle() { if (time < 10) { l += 3; alpha -= 10; time++; } } public void drawCircle(Graphics2D g2) { Color color = new Color(a, b, c, alpha); g2.setColor(color); g2.fillOval(centerX - l/2, centerY - l/2, l, l); } public boolean isEnd() { return time >= 10; } }
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How to add scroll bar in JPanel?
Software Programming • java swing layout • • terrea

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Avoid using absolute layout unless it is of extreme need and know the consequences of this, because absolute layout makes it difficult to maintain the screen and makes its application look different depending on the monitor and resolution being performed.There are several https://docs.oracle.com/javase/tutorial/uiswing/layout/visual.html so you don't have to worry about positioning or manual component organization. Not counting that the use of layouts makes your code easier to give maintenance than being inserting a lot of setbounds, and if you need to change the position of some component, you will have to reposition all manually.In the code presented, the problem is solved in an alternative and rather simple way: using https://docs.oracle.com/javase/9/docs/api/java/awt/GridLayout.html . This layout organizes the components of a container in the form of a grid, where you define how many rows and columns it must possess. In your case, the number of rows is indefinite, so just pass 0 in the first parameter of the constructor( https://docs.oracle.com/javase/9/docs/api/java/awt/GridLayout.html#GridLayout-int-int- ) and leave on account of the layout.And for the scroll to work properly, you need to create a panel with the layout informed, and add this panel to JScrollPane, and don't add the botoes directly, so the scrollpane won't know which component it will be based on the size to display the scroll.I made some changes to your code by removing the absolute layout, since mixing relative and absolute layouts will not bring the expected result:import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.border.EmptyBorder; import java.awt.Dimension; import java.awt.GridLayout; import javax.swing.JButton; import javax.swing.JScrollPane; public class GridLayoutButtonsTest extends JFrame { private JPanel contentPane; private int qtButton = 0; public static void main(String[] args) { GridLayoutButtonsTest frame = new GridLayoutButtonsTest(); frame.setVisible(true); } public GridLayoutButtonsTest() { setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); setPreferredSize(new Dimension(500, 500)); contentPane = new JPanel(); contentPane.setBorder(new EmptyBorder(5, 5, 5, 5)); setContentPane(contentPane); JScrollPane scroll = new JScrollPane(); scroll.setPreferredSize(new Dimension(464, 439)); JPanel panel = new JPanel(); panel.setLayout(new GridLayout(0, 1, 10, 10)); for(int i = 0; i < 15; i++) { panel.add(gerarButton()); } scroll.setViewportView(panel); contentPane.add(scroll); pack(); } public JButton gerarButton() { qtButton++; JButton NewButton = new JButton(String.valueOf(qtButton)); return NewButton; } } Result: More usage information about this layout can be found in https://docs.oracle.com/javase/tutorial/uiswing/layout/grid.html .
How to remove json from the ajax response to the table
Software Programming • javascript java ajax jsp • • briley

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The problem was connected to the server side. The data were in the cycle, so the client was called "casha."
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Software Programming • javascript vue.js vuex • • tahishae

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You could use the Store to call multiples, for example I have it set like this:import Vue from 'vue' import Vuex from 'vuex' // importas los getters, mutations, actions y state import state from "./state" import getters from "./getters" import mutations from "./mutations" import actions from "./actions" Vue.use(Vuex) creas las constantes // import moduleTodo from './todo/moduleTodo.js' import moduleCalendar from './calendar/moduleCalendar.js' import moduleChat from './chat/moduleChat.js' // import moduleEmail from './email/moduleEmail.js' import moduleAuth from './auth/moduleAuth.js' import moduleUser from './user-management/moduleUserManagement.js' import moduleECommerce from './eCommerce/moduleECommerce.js' export default new Vuex.Store({ getters, mutations, state, actions, modules: { // todo: moduleTodo, calendar: moduleCalendar, chat: moduleChat, // email: moduleEmail, auth: moduleAuth, user: moduleUser, eCommerce: moduleECommerce, }, strict: process.env.NODE_ENV !== 'production' }) I personally prefer to have mutations, actions, getters and state separately for each module, so I keep organized my codeonce you define the modules in the store/index.js file you can create a new folder for the new states, but remember to create the file that will have the logic,if you note in moduleUser I call the user-management directory and then the moduleUserManagement.js file that is within user-management, this file has the log, I leave an example below://IMPORTEE LO QUE DESEO MANTENER POR SEPARADO, SI A TI SOLO TE INTERESA EL STATE PUEDES QUITAR EL RESTO import state from './moduleUserManagementState.js' import mutations from './moduleUserManagementMutations.js' import actions from './moduleUserManagementActions.js' import getters from './moduleUserManagementGetters.js' export default { isRegistered: false, namespaced: true, state: state, mutations: mutations, actions: actions, getters: getters } And finally create the file that states contain, in my case is moduleUserManagementState.jsexport default { role: [], } I hope it's clear and I hope it helps you with something!, greetings!
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How is the use of the jet in this example correct?
Software Programming • java generics reflexia annotations okhttp • • gionna

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The first thing that goes into the eye is... methods[i].isAnnotationPresent♪ The best method for obtaining a set of declared annotations method.getDeclaredAnnotations()♪ And as the array contains objects, we can get them SimpleName: annotation.annotationType().getSimpleName() and then safely wrapped in switchThe second is the duplicated mop filling code. In my view, it is easier to take into a separate method with all associated checks.The third is to use patherne dependency injection. parse accepts at the entrance any number of facilities and further analyses. A further method could also be taken at the inlet of a set of methods and validated/filtrated. In short, divide the code into logical parts (methods) and transfer facilities to them.Output of the code below Result: {/api/v1/smart/status=[GET, POST]}public class Main { private static Map<String, List<String>> map = new HashMap<>(); public static void main(String[] asd) throws InstantiationException, IllegalAccessException { parse(new Main(), new Integer("1")); System.out.println("Result: " + map); } private static void parse(Object... objects) { for (Object o : objects) { for (Method method : o.getClass().getDeclaredMethods()) { for (Annotation annotation : method.getDeclaredAnnotations()) { switch (annotation.annotationType().getSimpleName()) { case "POST": addToMap(((POST) annotation).value(), "POST"); break; case "GET": addToMap(((GET) annotation).value(), "GET"); break; case "DELETE": case "PUT": case "HEAD": case "OPTIONS": } } } } } private static void addToMap(String path, String httpMethod) { if (path != null) { List<String> list = map.get(path); if (list == null) { list = new ArrayList<>(); } list.add(httpMethod); map.put(path, list); } } @GET("/api/v1/smart/status") private void fooMeethod() {} @POST(value = "/api/v1/smart/status") private void barMeethod() {} @Retention(RUNTIME) @Target({METHOD}) private @interface GET { String value(); } @Retention(RUNTIME) @Target({METHOD}) private @interface POST { String value(); } } I hope so.
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Multiple data-category
Software Programming • javascript html jquery • • meriah

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Separate categories to the massconst categories = $(this).data('category').split(','); a condition at which pointcheckedArr.some(c => categories.includes(c)) I guess it's better to be in place. each-toggle Do what filter-toggle
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What brings this fragment of code? 'full = tope literal=buff.length; '
Software Programming • java • • magpie

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Your question seemed curious. And I recognize that I've never seen code written like that.We have to take into account the following:lleno is a boolean type variable (true/false)>= It's a comparison operator.length calculates the size of an array (in the example, to simplify I have taken a string and calculated its size with the method lenght()Then the line:lleno = tope>=buff.length; Makes a comparison and assigns directly to the variable lleno the result (true or falseThat comparison.I did this test code to confirm:Código: http://rextester.com/XQL32500 import java.util.*; import java.lang.*; class Rextester { private static int tope = 0; public static boolean lleno = false; public static void main(String args[]) { String buff="Ok"; lleno = tope>=buff.length(); System.out.println(lleno); buff=""; lleno = tope>=buff.length(); System.out.println(lleno); } } Resultadofalse true
Multiple symbolic links
Software Programming • linux • • Demir

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In view of the information you have provided in the question (at my request in several comments that were then deleted to "remove noise"), we can reach the following conclusions:When you put python without more on the command line, what will be attempted to run is /usr/bin/python (this tells us. which python)But /usr/bin/python in fact it is not the executable, but only a reference (link symbolic to another file). Specifically /etc/alternatives/python3 (this is what one of the ls -ld)For your part /etc/alternatives/python3 is another symbolic link, which points to /usr/bin/python3.8And /usr/bin/python3.8 This is yes. It's an executable. I deduct it by its size (5134032 as seen in the last image).Therefore before the command python who ends up being executed is /usr/bin/pyton3.8.Let's see now what happens to the command python3.To start the command which python3 flaws and returns nothing. I suspect that it is because the attempted execution ended in an infinite redirect loop, so the information of which command was not saved.I'll make the hypothesis that the command that was attempted to execute was /usr/bin/python3 (as in the previous case we saw that when we put python started to try /usr/bin/python). It also makes sense because the route /usr/bin is one of the first to search for executable commands.If we look (second screenshot) what's in /usr/bin/python3 we see it's a symbolic link that points to /etc/alternatives/python3. We see that it also comes out in red in that list, which already alerts us that something is wrong.If we look /etc/alternatives See that python3 is a symbolic link that points to /usr/bin/python3! I mean, one link points to another, but the second again points to the first. Python has become a https://es.wikipedia.org/wiki/Ur%C3%B3boros It's no wonder he's making the mistake you've seen. If the operation follows the symbolic links it will never end because it only takes you from one to another without ever reaching the final executable file. After a few iterations the operation gets tired and tells you that "too many symbolic links".How to fix itNow that we know this, how to fix it? It should be done. /usr/bin/python Aim to /etc/alternatives/python and that this in turn points to /usr/bin/python2 (which in turn points to /usr/bin/python2.7) That would make it possible to put python the final executable is version 2.7.To accomplish this we will use the command ln -s that allows to create symbolic links (previously the links that were wrong must be deleted). This can only be done by the administrator, so you'll have to put sudo in front of the commands. These would be:rm /etc/alternatives/python ln -s /usr/bin/python2 /etc/alternatives/python rm /usr/bin/python ln -s /etc/alternatives/python /usr/bin/python Similarly we erase the symbolic links that prevented the correct execution of python3 and put the good ones:rm /etc/alternatives/python3 ln -s /usr/bin/python3.8 /etc/alternatives/python3 rm /usr/bin/python3 ln -s /etc/alternatives/python3 /usr/bin/python3 With this putting python3 will finally run version 3.8 (since that is to which the link in the /etc/alternatives/python3)
MongoDB, search multiple fields for multiple values
Software Programming • mongodb • • briley

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The question is not understood well. But if you had a collection prueba documents{ "title" : "Don Quijote de la Mancha", "author" : "Miguel de Cervantes" } { "title" : "FuenteOvejuna", "author" : "Lope de Vega" } { "title" : "Niebla", "author" : "Miguel de Unamuno" } { "title" : "Miguel y el Dragón", "author": "Elizabeth Heck"} The consultationdb.prueba.find({ $or: [{author:/miguel/i}, {title: /miguel/i}] }); I'd pay you back.{ "title" : "Don Quijote de la Mancha", "author" : "Miguel de Cervantes" } { "title" : "Niebla", "author" : "Miguel de Unamuno" } { "title" : "Miguel y el Dragón", "author": "Elizabeth Heck"} If you do not know the fields of each document you cannot do such a query, so when inserting a document like:{ "nombre" : "san miguel" } It wouldn't help you look for the fields "title" or "author". Hair... what you can do is create a text index on the collection by indexing all fieldsdb.prueba.createIndex({ "$**": "text" }); And then search using the operator $text in combination with $search. This operator does not accept regular expressions as a parameter (only strings), but you can tell him to be case-insensitive:db.prueba.find({ $text : { $search: 'Miguel', $caseSensitive:false } }); And you will search in all indexed fields (in this case, all the fields of the collection) for the match of the partial text "Miguel", so you will return:{ "title" : "Don Quijote de la Mancha", "author" : "Miguel de Cervantes" } { "title" : "Niebla", "author" : "Miguel de Unamuno" } { "title" : "Miguel y el Dragón", "author": "Elizabeth Heck"} { "nombre": "san miguel"} PS: $search also allows you to ignore accents and diacritics in general by putting $diacriticSensitive : falseEDIT based on commentary:Suppose you insert a new record:{ "apodo" : "miguelito", "direccion":"Avenida el Quijote 455" } That record contains "Miguel" and "Quijote" and you want all the records that contain both words. If you do:db.prueba.find({ $text : { $search: 'Miguel Quijote'} }); He'll bring you all the records containing "Miguel" O Get off me. It's not what you want.).You can ask for an exact match making:db.prueba.find({ $text : { $search: '"Miguel Quijote"'} }); But no document has that exact text, because Miguel and Quixote are in different fields. (so, It's no good either.)How do you do then? You can ask more than an exact match:db.prueba.find({ $text : { $search: '"Miguel" "Quijote"' } }); And that returns:{ "title" : "Don Quijote de la Mancha", "author" : "Miguel de Cervantes" }, { "apodo" : "miguelito", "direccion":"Avenida el Quijote 455" } The only two records that contain both "Miguel" and "Quijote"
Use Maven or Spring Boot profiling?
Software Programming • java spring boot maven • • Mystic

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In fact, if you already want to pack in a specific profile, you will use both. The first form is through Spring Boot itself, creating multiple .properties files in the model applications-{profile}.propertiesFor example, we have a file for production environment configuration application-prd.properties and a file for configuration of the homologation environment application-hml.propertiesAnd for the application to use the production or environment settings, it should be added in the java command:java -jar -Dspring.profiles.active={profile} aplicacao.jar For example:java -jar -Dspring.profiles.active=prd aplicacao.jar So far we can perform our application in every profile we have. But note that this spring boot profiling feature is to be used in runtime and does not allow you to packaging already in a specific profile. It is in this case that the maven profiling enters the file pom.xml:<profiles> <profile> <id>lcl</id> <properties> <activatedProperties>lcl</activatedProperties> </properties> </profile> <profile> <id>hml</id> <properties> <activatedProperties>hml</activatedProperties> </properties> </profile> <profile> <id>prd</id> <properties> <activatedProperties>prd</activatedProperties> </properties> </profile> </profiles> But that's not enough, all we did there was create a "variable" called activatedProperties depending on the profile receives a value. In the face of will we create a application.properties, which is the default configuration file for reading Spring Boot and will be read in place of the other 3 we created and we will inform there the spring variable spring.profiles.active, to which we were configuring during the execution mode, and to pass this "variable" activatedProperties. Our file application-properties.xml It would be like this:spring.profiles.active=@activatedProperties@ The maven will not replace the "variable" delimited between the @s while we do not inform it to filter these files. So, too pom.xml we'll add one <resource>:<build> ... <resources> <resource> <directory>src/main/resources</directory> <filtering>true</filtering> </resource> </resources> </build> Okay, now yes. We can make the package through the command:mvn package -P{profile} For example:mvn package -Pprd When we run this command, the following will happen basically:Command mvn package -Pprd is executed.The maven will see which profile we are requesting through -P{profile} that is the profile prd.The maven will discover the value of the variable activatedProperties that profile.The maven will scan all files inside src/main/resources and will identify in the file application.properties the delimiter @activatedProperties@ and will literally replace by value the variable activatedProperties.Spring Boot will runSpring Boot will read the default configuration file application.properties found.In this file there will be the following configuration: spring.profiles.active=prd and, with that, the file application-prd.properties will be read.
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Laravel multiple filter
Software Programming • laravel • • Nykeriab

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I've never done this way. I'd do something like that: return $model->whereHas('attributes', function($query) use ($gender) { $query->where('gender', $gender); }) ->with('attributes') ->get(); Well, naturally, there should be arrtibutes() in the model, describing the connection to the attributes.
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Issues with Java graphs
Software Programming • java graph • • Kadir

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The EOF means end of the file. Since this is used in a context where you read from the default entry, it means the end of System.in.First, let's ball a class that represents an edge:public final class Aresta { private final int origem; private final int destino; public Aresta(int origem, int destino) { this.origem = origem; this.destino = destino; } public static Aresta parse(String s) { String[] array = s.split(" "); return new Aresta( Integer.parseInt(array[0].trim()), Integer.parseInt(array[1].trim())); } public int getOrigem() { return origem; } public int getDestino() { return destino; } @Override public String toString() { return origem + "->" + destino; } } You can read all input lines like this (Java 10+): public static Stream<String> linhas(Scanner s) { Supplier<Optional<String>> sup = () -> { try { return Optional.of(s.nextLine()); } catch (NoSuchElementException e) { return Optional.empty(); } }; return Stream.generate(sup).takeWhile(Optional::isPresent).map(Optional::get); } This method works by creating a https://docs.oracle.com/javase/10/docs/api/java/util/stream/Stream.html with lines obtained through https://docs.oracle.com/javase/10/docs/api/java/util/Scanner.html#nextLine() .However, the method nextLine() launch one NoSuchElementException when the entry is over, and that's why this exception is captured and the return placed within a https://docs.oracle.com/javase/10/docs/api/java/util/Optional.html .With https://docs.oracle.com/javase/10/docs/api/java/util/stream/Stream.html#takeWhile(java.util.function.Predicate) , we can accept the elements of Stream until Optional empty appear, disregarding the results from that point. See that after that, all elements Optional will not be empty, we use .map(Optional::get) to unpack the element contained in Optional. The result is one Stream<String> containing the contents of the lines read.And then you can get one Stream<Aresta> So: public static Stream<Aresta> arestas(Scanner s) { return linhas(s).map(Aresta::parse); } You still need to represent your problem as a whole, including the line with the numbers C and P. We can create a class for this as well:public final class Problema { private final int numeroCidades; private final List<Aresta> arestas; public Problema(int numeroCidades, List<Aresta> arestas) { this.numeroCidades = numeroCidades; this.arestas = arestas; } public static Problema parse(Scanner s) { String primeiraLinha = s.nextLine(); String[] partes = primeiraLinha.split(" "); int c = Integer.parseInt(partes[0].trim()); List<Aresta> arestas = LerLinhas.arestas(s).collect(Collectors.toList()); return new Problema(c, arestas); } public int getNumeroCidades() { return numeroCidades; } public List<Aresta> getArestas() { return arestas; } @Override public String toString() { return "{c=" + numeroCidades + ", p=" + arestas.size() + ", arestas=" + arestas + "}"; } } To test this:public class LerLinhas { public static void main(String[] args) { Scanner s = new Scanner(System.in, StandardCharsets.UTF_8); Problema p = Problema.parse(s); System.out.println(p); } public static Stream<Aresta> arestas(Scanner s) { return linhas(s).map(Aresta::parse); } public static Stream<String> linhas(Scanner s) { Supplier<Optional<String>> sup = () -> { try { return Optional.of(s.nextLine()); } catch (NoSuchElementException e) { return Optional.empty(); } }; return Stream.generate(sup).takeWhile(Optional::isPresent).map(Optional::get); } } Testing with this entry:5 4 2 3 1 4 2 2 4 3 Here's the way out:{c=5, p=4, arestas=[2->3, 1->4, 2->2, 4->3]} So, with that you already get an instance of Problema ready for you to work. In this way, you can focus on the most interesting parts of the problem without worrying about the part of reading and interpreting the given entry. Note that you do not need to worry about cases where entries are malformed, because URI never runs the program sent that way.Note that I am not even giving myself the job of reading the value of P here. His value can be deducted directly from the number of lines read.

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