JSTL arraylist。 值是空的

Question

i was searching for the same problem as mine, but i didn't find anything. This is my problem:

I have ArrayList which includes beans. My beans is class 'Row'. There are setters and getters.

This is method from Database class:

public ArrayList<Row> getDatalist() {
    datalist = new ArrayList<Row>();
    try {
        String query = "SELECT * FROM ...";
        ResultSet r = s.executeQuery(query);
        while(r.next()) {
            Row row = new Row();
            row.setLocation(r.getString(4));
            row.setVolume(r.getInt(3));
            row.setTime(r.getTime(5));
            row.setDate(r.getDate(5));
            datalist.add(row);
        }
    } catch (SQLException e) {
        e.printStackTrace();
    }
    return datalist;
}

My servlet:

    ArrayList<Row> rows = db.getDatalist();
    request.setAttribute("rows", rows);
    request.getRequestDispatcher("/main.jsp").forward(request,response);

And at least 'main.jsp':

<c:forEach var="row" items="${rows}">
      <c:out value="${row.location}"></c:out>
</c:forEach>

The problem is that ${row.location} is empty. My page source:

<c:forEach var="row" items="[webservice.model.Row@1e41769, webservice.model.Row@1bd0815, webservice.model.Row@15dd716, webservice.model.Row@1d40d08]">

      <c:out value=""></c:out>

</c:forEach>

Any idea? Thanks a lot.

Answer 1

Well, your page source indicates the problem clearly: the c tags aren't interpreted by the container. This means that you forgot to declare the c taglib at the top of the JSP:

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

Answer 2

be sure you have set this：

<%@ page isELEnabled ="true"%>

to make el expression enable。