Display list of values on JSP using Spring

I would like to display my List of values in my jsp view, but i am not able to do this.

Here is my controller class below, which is only add List to the ModelAndView map and than it redirects to my index.jsp page.

EmployeeController

@Controller
public class EmployeeController {

@RequestMapping(value={"/employee"}, method = RequestMethod.GET)
public String listEmployee(){    
    System.out.println("Kontroler EmployeeController");
    LinkedList<String> list = getList();
    ModelAndView map = new ModelAndView("index");
    map.addObject("lists", list);

    return map.getViewName();
}

private LinkedList<String> getList(){
    LinkedList<String> list = new LinkedList<>();

    list.add("Item 1");
    list.add("Item 2");
    list.add("Item 3");

    return list;
}

}

index.jsp

<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>Welcome to Spring Web MVC project</title>
</head>

<body>
    <h1>Index page</h1>
    <h1>${msg}</h1>
    <a href="/MavenHello/employee">Zaměstnanci</a>
</body>
    <c:if test="${not empty listEmployee}">

    <ul>
        <c:forEach var="listValue" items="${listEmployee}">
            <li>${listValue}</li>
        </c:forEach>
    </ul>

</c:if>

I am able to access the controller, because every time I hit "Zaměstnanci", the System.out.println("Kontroler EmployeeController") prints "Kontroler EmployeeController" in to Tomcat Log, but the index.jsp page is blank.

Please, can someone give me an advice?

As you are populating ModelAndView return ModelAndView itself and not map.getViewName() which return only name of the name without data as stated in docs:

public String getViewName() Return the view name to be resolved by the DispatcherServlet via a ViewResolver, or null if we are using a View object.

as follows:

@RequestMapping(value = { "/employee" }, method = RequestMethod.GET)
public ModelAndView listEmployee() {
    System.out.println("Kontroler EmployeeController");
    LinkedList<String> list = getList();
    ModelAndView map = new ModelAndView("index");
    map.addObject("lists", list);

    return map;
}

Secondly, you are missing jstl tag <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%> on your index page and variable name you given to list is "lists" so iterate over "lists" rather than "listEmployee", as follows:

<html>
<head>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Welcome to Spring Web MVC project</title>
</head>

<body>
    <h1>Index page</h1>
</body>

<c:if test="${not empty lists}">
    <c:forEach items="${lists}" var="lists">
       ${lists}
</c:forEach>
</c:if>

Also, make sure you have JSTL dependency in your classpath:

<dependency>
  <groupId>jstl</groupId>
  <artifactId>jstl</artifactId>
  <version>1.2</version>
</dependency>

Just add Model to your controller method params and then add attribute to this model.

RequestMapping(value={"/employee"}, method = RequestMethod.GET)
public String listEmployee(Model model){    
    System.out.println("Kontroler EmployeeController");
    LinkedList<String> list = getList();
    model.addAttribute("lists", list);

    return "index";
}

One more way to do this, is to return ModelAndView instead of String

@RequestMapping(value={"/employee"}, method = RequestMethod.GET)
public ModelAndView listEmployee(){    
    System.out.println("Kontroler EmployeeController");
    LinkedList<String> list = getList();
    ModelAndView map = new ModelAndView("index");
    map.addObject("lists", list);

    return map;
}

Just choose which way is better for you.

And also change listEmployee in your index page to lists as in the ModelAndView you have an attribute as lists not listEmployee`.

Change the key name and try it : listEmployee --> lists as you are setting it as map.addObject("lists", list);

<ul>
    <c:forEach var="listValue" items="${lists}">
        <li>${listValue}</li>
    </c:forEach>
</ul>

来源：https://stackoverflow.com/questions/42054829/display-list-of-values-on-jsp-using-spring

标签

java

Spring

jsp

spring-mvc

modelandview