EISTI-ING1-GI
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Java-2017-2018


			
				
					
						
						
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<div class="doctitle">Saisie de chaînes dans la console</div>
<nav id="TOC">
<ul>
<li><a href="#saisir-des-chaînes-dans-la-console-en-java">Saisir des chaînes dans la console en Java</a><ul>
<li><a href="#introduction">Introduction</a></li>
<li><a href="#lecture-de-valeurs-depuis-la-console">Lecture de valeurs depuis la console</a></li>
<li><a href="#information-à-propos-de-la-méthode-system.console">Information à propos de la méthode System.console()</a></li>
</ul></li>
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<h1 id="saisir-des-chaînes-dans-la-console-en-java">Saisir des chaînes dans la console en Java</h1>
<h2 id="introduction">Introduction</h2>
<p>Cette annexe donne quelques pistes pour permettre la récupération de chaînes de caractères saisies par l’utilisateur depuis un programme.</p>
<p>Ce programme est lancé ici dans une console.</p>
<h2 id="lecture-de-valeurs-depuis-la-console">Lecture de valeurs depuis la console</h2>
<p>Le code suivant permet de récupérer des valeurs depuis les entrées clavier:</p>
<div class="sourceCode" id="cb1"><pre class="sourceCode java"><code class="sourceCode java"><a class="sourceLine" id="cb1-1" data-line-number="1"><span class="bu">Scanner</span> in = <span class="kw">new</span> <span class="bu">Scanner</span>(<span class="bu">System</span>.<span class="fu">in</span>);</a>
<a class="sourceLine" id="cb1-2" data-line-number="2"></a>
<a class="sourceLine" id="cb1-3" data-line-number="3"><span class="bu">String</span> s = in.<span class="fu">next</span>();</a>
<a class="sourceLine" id="cb1-4" data-line-number="4"><span class="dt">int</span> i = in.<span class="fu">nextInt</span>();</a></code></pre></div>
<p>Le programme suivant fait une démonstration de cela:</p>
<div class="sourceCode" id="cb2"><pre class="sourceCode java"><code class="sourceCode java"><a class="sourceLine" id="cb2-1" data-line-number="1"></a>
<a class="sourceLine" id="cb2-2" data-line-number="2"><span class="kw">import</span><span class="im"> java.util.Scanner;</span></a>
<a class="sourceLine" id="cb2-3" data-line-number="3"></a>
<a class="sourceLine" id="cb2-4" data-line-number="4"><span class="kw">public</span> <span class="kw">class</span> LectureValeur {</a>
<a class="sourceLine" id="cb2-5" data-line-number="5">    <span class="kw">private</span> <span class="bu">Scanner</span> scanner = <span class="kw">new</span> <span class="bu">Scanner</span>(<span class="bu">System</span>.<span class="fu">in</span>);</a>
<a class="sourceLine" id="cb2-6" data-line-number="6"></a>
<a class="sourceLine" id="cb2-7" data-line-number="7">    <span class="kw">public</span> <span class="dt">static</span> <span class="dt">void</span> <span class="fu">main</span>(<span class="bu">String</span>[] args) {</a>
<a class="sourceLine" id="cb2-8" data-line-number="8">        LectureValeur lectureValeur = <span class="kw">new</span> <span class="fu">LectureValeur</span>();</a>
<a class="sourceLine" id="cb2-9" data-line-number="9"></a>
<a class="sourceLine" id="cb2-10" data-line-number="10">        <span class="bu">String</span> valeur = lectureValeur.<span class="fu">demanderChaine</span>(<span class="st">&quot;Veuillez entrer une chaîne:&quot;</span>);</a>
<a class="sourceLine" id="cb2-11" data-line-number="11">        <span class="bu">System</span>.<span class="fu">out</span>.<span class="fu">println</span>(<span class="st">&quot;La valeur entrée est: &quot;</span>+valeur);</a>
<a class="sourceLine" id="cb2-12" data-line-number="12">    }</a>
<a class="sourceLine" id="cb2-13" data-line-number="13"></a>
<a class="sourceLine" id="cb2-14" data-line-number="14">    <span class="kw">public</span> <span class="bu">String</span> <span class="fu">demanderChaine</span>(<span class="bu">String</span> message){</a>
<a class="sourceLine" id="cb2-15" data-line-number="15">        <span class="bu">System</span>.<span class="fu">out</span>.<span class="fu">println</span>(message);</a>
<a class="sourceLine" id="cb2-16" data-line-number="16">        <span class="kw">return</span> scanner.<span class="fu">next</span>();</a>
<a class="sourceLine" id="cb2-17" data-line-number="17">    }</a>
<a class="sourceLine" id="cb2-18" data-line-number="18">}</a></code></pre></div>
<h2 id="information-à-propos-de-la-méthode-system.console">Information à propos de la méthode System.console()</h2>
<p>Le code suivant permet de récupérer des valeurs mais ne marchera pas sous Eclipse (ou dans un IDE):</p>
<div class="sourceCode" id="cb3"><pre class="sourceCode java"><code class="sourceCode java"><a class="sourceLine" id="cb3-1" data-line-number="1"><span class="bu">String</span> reponse = <span class="bu">System</span>.<span class="fu">console</span>().<span class="fu">readLine</span>();</a>
<a class="sourceLine" id="cb3-2" data-line-number="2"><span class="bu">System</span>.<span class="fu">out</span>.<span class="fu">println</span>(reponse);</a></code></pre></div>
<p>Vous pouvez cependant utiliser ce code si vous utilisez le programme en ligne de commande.</p>
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