如何在Java中使用AJAX？ [重复]

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                        <a href="/questions/4112686/how-to-use-servlets-and-ajax" dir="ltr">How to use Servlets and Ajax?</a>
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                                (7 answers)
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            <div class="grid--cell mb0 mt8">Closed <span title="2016-05-07 07:01:45Z" class="relativetime">3 years ago</span>.</div>
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I have the following javaScript function:

function loadSomething() {
    var xhttp;
    if (window.XMLHttpRequest) {
        xhttp = new XMLHttpRequest();
        } else {
        // code for IE6, IE5
        xhttp = new ActiveXObject("Microsoft.XMLHTTP");
    }

    xhttp.open("GET", "javaservlet.java", true);
    xhttp.send();
}

and I want to get, lets say an int value from a Java Servlet - "javaservlet". What code should I write in javaservlets doGet() method in order to send a value, so I can get and use it in javaScript? Thank you!

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Answer 1

You need to provide url mapping for that servlet in web.xml. I am assuming your servlet class name is JavaServlet.

<servlet>
<description></description>
<display-name>JavaServlet</display-name>
<servlet-name>JavaServlet</servlet-name>
<servlet-class>JavaServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>JavaServlet</servlet-name>
<url-pattern>/javaServlet</url-pattern>
</servlet-mapping>

Now change the following in javascript code to send GET request to JavaServlet.

 function loadSomething()
{
    var xhttp;
    if (window.XMLHttpRequest) {
        xhttp = new XMLHttpRequest();
        } else {
        // code for IE6, IE5
        xhttp = new ActiveXObject("Microsoft.XMLHTTP");
    }

    xhttp.open("GET", "javaServlet", true);
    xhttp.send();
}