将值从Java传递到jsp或servlet

Question

i am working on a project. my work is retrieve data from database and displaying them. if required sent to next page for further processing. my problem is i got value from database and i want to send it another jsp or servlet using href. value i am retrieving is :

        <%=special.getString("id")%>

send it to:

      <a href="new.jsp?id=<%=special.getString("id")%>" class="action_button">Buy Now</a>

but when send data like this error is

is that correct? how do i do it? what is the correct method. i am struck here for long time please help me.

Answer 1

在id周围使用单引号，而不是双引号。

"new.jsp?id=<%=special.getString('id')%>"

Answer 2

Use single quote inside double quote. I am trying to type code but not able to type. now it should work

Answer 3

You need to escape your quotes first or use single quotes so that your double quotes can work:

Note: Untested.

<a href='new.jsp?id=<%=special.getString("id")%>' class="action_button">Buy Now</a>

Answer 4

I see in your error message it says DOUBLE_WHITESPACE in QUERY . I would suggest you try encoding you url.

  <% String id=java.net.URLEncoder.encode(special.getString("id") , "UTF-8");%>
  <a href='new.jsp?id=<%=id%>' class="action_button">Buy Now</a>

Answer 5

If you're serious about JSP development ditch scriptlets (which went out of common use 10+ years ago) and familiarize yourself with the Java Standard Tag Libraries and JSP Expression Language.

I am not quite sure what 'special' is here, however using EL your code will look something like the below:

<!-- special is an object with a method getId()-->
<a href="new.jsp?id=${special.id}" class="action_button">Buy Now</a>

or

<!-- special is an object with a method getString(String key) -->
<a href="new.jsp?id=${special.getString('id')}" class="action_button">Buy Now</a>

If this doesn't work then there is no bean with key 'special' in any scope.

Note that if you are working with a database in your JSP you should consider refactoring to use the standard JSTL SQL tags. See below for an example:

http://www.tutorialspoint.com/jsp/jstl_sql_query_tag.htm

See also:

http://www.tutorialspoint.com/jsp/jsp_standard_tag_library.htm

http://beginnersbook.com/2013/11/jsp-expression-language-el/

*Note for the second example to work your app need to be compliant with the Servlet 3 specification (as passing mthod params was nut supported in EL before this). See further: https://stackoverflow.com/a/6337222/1356423