从jsp页面调用Java方法

Question

I have jsp page that imports Testing.java

<jsp:useBean id="test" scope="session" class="Testing" />
<jsp:useBean id="sb" scope="session" class="SessionBean" />
<jsp:useBean id="eb" scope="session" class="ErrorBean" />

I need to call public method that is in Testing class after user confirms changes.

this is what I have so far:

<tr>
    <td align="left">
        <a href="<%=test.persistPrintingInfo(eb,sb) %>" >
        <img src="../images/update.gif" OnClick="if( !confirm('Update printing information?')) return false"></a>
    </td>
</tr>

Does anyone know how to do this?

Can I maybe call javascript method and call persistPrintingInfo() through javascript?

Answer 1

您可以使用这种方式，尽管有更好的方法使用servlet。

<%com.example.Testing.yourMethod()%>

Answer 2

the page has been sent by the server to your browser. while javascript can modify the content of your page , in order to call a bean's method you must make a call to the server(a request to the servlet) beacause the bean lives on the server side. and this call can be made by creating an url mapped to the servlet, or a form whose action is the servlet

`<FORM ACTION="${pageContext.request.contextPath}/sampleServlet">`

if the form's method is GET, then on the doGet() method of the servlet you call your bean's method.

this form does not need to contain any kind of field. it is created just to make a request to the servlet. while you would normally click the submit button to proceed to the action, this time we will submit the form through javascript. with some javascript tricks, i think this form can also be hidden, because you don't actually need it to be displayed in your page

so you simply create this form in your jsp, and submit it through javascript , like this: on your link, you will have onClick=myJavascriptMethod() ; in your jsp, you create a javascript block

<script type="text/javascript"> function myJavascriptMethod)=() { document.forms["myform"].submit(); } </script>

Answer 3

a second approach which i found while googling is this one:

How do I pass current item to Java method by clicking a hyperlink or button in JSP page?

in your case, the code will be

<a href="newPage.jsp"><img.. ></a>

the newPage.jsp will contain just

<%yourPackage.YourClass.yourMethod()%>