Posts by Lucas Pletsch • 787 points
88 posts
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answer14930
viewsQ: Uncaught Syntaxerror: Unexpected token u in JSON at position 0
In my html I am using Javascript to try to recover a Json object saved in localStorage. I am using Google Chrome. First I get the value of the "name" attribute of my Json object that is in…
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answer142
viewsQ: Load another html doc instead of the current one using pure Javascript
In this work of the facul, estu making an app with several menus, if I do everything in a single html, will get huge file. So by clicking the options on a given menu, I would like to continue…
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answers655
viewsQ: How to save Javascript objects in JSON format in localStorage, and then deserialize them?
I am getting values from a form in html, then I want to use a function to take these values and create an object, making them attributes of this object. Then, I want to store this object in the…
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answers2191
viewsQ: Is it possible to save <form> forms in localStorage with pure Javascript?
I’m a beginner in Javascript and I’m making a prototype application for a college job, and I didn’t want to use a database or anything, because it’s not worth it, I just need to test the functioning…
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answer164
viewsQ: Centering buttons on a div does not work
I created a div containing several buttons, and I set in two of these buttons (those of the second row of buttons) the attribute align = "center", html itself. But it was the same thing as nothing,…
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answer223
viewsQ: Figure drawn in canvas is not appearing
I made the code below to create a canvas that draws in its space a red rectangle. However, nothing appears. I can’t find any syntax error. I’m using Google Chrome: <!DOCTYPE html> <html>…
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answer119
viewsQ: And in what context can the use of JSON be advantageous compared to the use of XML (in web applications)?
I have this question in a simulated test. Besides the ease of writing the Json, and the fact that it is well oriented to objects, what could be the advantages? The topic: Why and when to use XML…
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answer27
viewsQ: Mouse eventlistener does not work
I took this example below the book "Eloquent Javascript" 2nd edition in Portuguese pg.184. The goal is to draw dots on the screen using clicks: every time the mouse is clicked, a blue dot is created…
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answers571
viewsQ: Perfect centralization of elements using Transform:Translate <style>
On another question I asked before, a user gave me an example of how I could perfectly centralize an html button on the screen. It was in this question: How to position a button anywhere on the…
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answers11440
viewsQ: How to position a button anywhere on the screen, in html
I’m trying to position a button type "button" in the center of the screen. For this, I put it in a div, and applied to that div one css that arrow your position on the window. However, the button…
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answer71
viewsQ: Reinserting elements elsewhere in Body, html and Javascript
I’m trying to store in a var, and then reinsert into the body 3 elements of the type "p". <body> <p> Um</p> <p> Dois </p> <p> Tres </p> .... In doing so:…
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answer382
viewsQ: Error : "No Persistence Provider for Entitymanager"
I have a project in Eclipse with an application that persists in the Postgresql 9.6 database through Hibernate, but Java is not recognizing the "persistence-Unit name" which is set in the…
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answer136
viewsQ: "The Java Exception has ocurred" error while running the Postgre JDBC driver
Follow my problem: 1 - I am using the Postgre 9.6 database. 2 - I downloaded and opened in ECLIPSE a project with example Java application with the use of Hibernate and Postgre that the teacher…
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answer53
viewsA: Error running Postgresql admin:
Solved: just click on Pgadmin4 to run it again that worked. Sometimes only connect on the third attempt.
postgresqlanswered Lucas Pletsch 787 -
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answer53
viewsQ: Error running Postgresql admin:
I downloaded Postgre 9.6 and installed everything "default". But when running the Postgre graphical interface, "pgadmin4" gives the following error: "The application server could not be contacted".…
postgresqlasked Lucas Pletsch 787 -
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answers664
viewsA: Error trying to run Eclipse: Java was Started but Return Exit code =13. PATH IS CORRECT
I needed to remove the 1.7 x86 and 1.8 x86 versions of jdk installed, with this windows program:…
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answers664
viewsQ: Error trying to run Eclipse: Java was Started but Return Exit code =13. PATH IS CORRECT
I deleted versions previous to Java 8 and now the eclipse does not want to run, the following error message appears: " Java was Started but Return Exit code =13.": There’s a similar topic: I’ve done…
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answer44
viewsQ: Javascript function does not execute when selecting a radio button
I created a Javascript function that needs to be executed every time one of the buttons on the radio button is selected. But nothing happens. Follow the code: <script> document.write( )…
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answers102
viewsQ: My first Javascript code doesn’t work. Now what?
I’m trying to run my first javascript. But when I click the button I created, the text that should appear on the screen does not appear. Where am I missing? My browser is updated so it should run…
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answer38
viewsQ: Frames formed by other htmls are not appearing
In my first HTML frame exercise, I created a document made up of two frames where each one is another HTML document, which is in the same folder as the initial document. The HTML of frames work…
htmlasked Lucas Pletsch 787 -
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answers12367
viewsQ: Image inserted in html does not want to appear
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN" "http://www.w3.org/TR/REC-html40/strict.dtd"> <HTML> <HEAD> <TITLE>Segundo HTML</TITLE> </HEAD> <BODY>…
htmlasked Lucas Pletsch 787 -
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answer171
viewsA: Changing the name of a table in the H2 Database Engine
I found the syntax: Example: ALTER TABLE TEST RENAME TO MY_DATA Reference: H2 Database Engine grammar manual: Available in : http://www.h2database.com/html/grammar.html#alter_table_rename_constraint…
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answer171
viewsQ: Changing the name of a table in the H2 Database Engine
I’m trying to change the name of a table in H2, but I can’t find the syntax. Does anyone know?
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answer312
viewsQ: Is concatenating values directly into the query problematic?
These days a guy told me: "avoid forming Sqls by concatenating pieces of Strings. To do this is to ask to have security problems with SQL injection, and for this reason is considered a bad…
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answer512
viewsQ: First() and next() methods do not work in Resultset, even when editing parameters
I need to do two iterations on the same ResultSet. For that I did the following: I set parameters in a Statement to make the cursor editable, according to my connection class constructor: public…
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answers749
viewsQ: How to find out in SQL which is the primary key of the table?
I am learning SQL, and ran into the following problem: I need to know which of the columns is the primary key of the table. Have some command I can use in SELECT to get as return that information?…
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answers323
viewsQ: How to format resultset printing via System.out.println in Java?
Hello, I am printing on the screen the result of a SELECT that I have stored in a resultset object (sql.Resultset). But it comes out "all crooked". I tried to use the " t" between each printed…
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answer940
viewsQ: Use a java Resultset to print an entire table on the screen
I know that with the resultset we can do several things with a SELECT done in some table. For example: I know that we can take a table and print its contents, listing which columns we want with…
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answer1578
viewsQ: What is an embedded database (Embedded)?
what is an embedded database, and what we call the "unbuilt"? For example: I’m trying to create a database by the H2 Database Engine, and it has two database options: Embedded or Server. You could…
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answer11590
viewsQ: What is Java & quot?
I wonder what it means " java. Example: used to form the name of an object: ClasseObjeto celula+""+col+"_"+lin = new ClasseObjeto();…
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answer1683
viewsQ: The difference between the Classpath environment variable and the . classpath files of JAR projects
when we install JDK, we create an environment variable called CLASSPATH, which has as its value the JAVA_HOME variable, which in turn has the address of jdk, which contains all libraries for Java…
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answer697
viewsA: Import org.apache.Commons.io.input library from Java to Eclipse
Well, according to user Jefferson Quesado, so that the dependencies declared on pom.xml be seen by my project in Eclipse, this project needs to be a "Java Project, but of the type Maven" which is a…
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answer697
viewsQ: Import org.apache.Commons.io.input library from Java to Eclipse
I need to use the class Reversedlinesfilereader, which belongs to the org.apache.Commons.io.input library. @Tommelo told me that I should include a dependency of this library in the archive pom.xml…
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answers1081
viewsQ: Get the contents of the last line of a Java file
I need to recover a file always the last line written. I know one way to do this would be: import java.io.FileInputStream; import java.io.InputStreamReader; import java.io.LineNumberReader; public…
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answers56
viewsQ: Set method does not work for filling object array
I created a class Funcionário, and in class Main create an array of objects of this type. I am now trying to set the attribute "position" of employees in a loop, but gives NullPointerException...…
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answer47
viewsQ: Man pages on Windows
in the Linux command terminal we can access the manual pages of the applications. Type man date. Is there anything equivalent in Windows cmd? For example, I wanted to know details of the tasklist…
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answers206
viewsQ: Network connections between processes within a machine
when giving the command netstat -na in the cmd of windows appear the network connections that are in progress on the machine. In my appeared several connections having as source and destination IP…
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answer407
viewsQ: Struct defined in file. c auxiliary (with definition of functions and structs) is not recognized in main
I’m doing a C project, and I have 3 files: 1 . c containing the definitions of functions and structs. 1 . h containing the prototypes of these functions and structs Ae1 . c containing the main. No .…