Question

我的java课程是：

public class Name{

  private String name;
  private ArrayList<Phone> phoneList;

  // plus getters and setters
}

public class Phone{

      private String phone;

      // plus getters and setters
}

我有一个NameList的ArrayList，如：

ArrayList<Name> nameList = some method that returns an ArrayList<Name>

我的servlet代码是：

protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

  ArrayList<Name> nameList = some method that returns an ArrayList<Name>

  request.setAttribute("nameList", nameList);
  RequestDispatcher rd = request.getRequestDispatcher("someJSP.jsp");
  rd.forward(request, response);
}

我的jsp代码是：

<c:choose>
  <c:when test="${not empty requestScope['nameList'] }">
    <c:forEach var="name" items="${requestScope[' nameList '] }">
      Name:${name.name }
        <c:choose>
          <c:when test="${not empty requestScope[' nameList.phoneList'] }">
            <c:forEach var="phone" items="${requestScope ['nameList.phoneList'] }">
              Phone:${phone.phone } </div>
            </c:forEach>
          </c:when>
          <c:otherwise>
         <span>The phone list is empty.</span>
          </c:otherwise>
      </c:choose>
    </c:forEach>
  </c:when>
</c:choose>

当我运行jsp文件时，nameList不为空，但电话列表为空。

不知何故电话列表丢失了，我不知道如何解决这个问题。

Answer 1

当我运行jsp文件时，nameList不为空，但是pone列表为空。，

因为您没有设置ponelist

的值

某种方式电话列表丢失

在servlet中没有任何方法从getter和setter中返回值，这并没有丢失，

  ArrayList<Name> nameList = some method that returns an ArrayList<Name>    
  request.setAttribute("nameList", nameList);
  RequestDispatcher rd = request.getRequestDispatcher("someJSP.jsp");
  rd.forward(request, response);

所以需要有另一个列表并设置类Phone的属性，如上所述，

  ArrayList<Phone> poneList = some method that returns an ArrayList<Phone>
  request.setAttribute("ponelist", ponelist);

希望这会有所帮助!!

Answer 2

我找到了解决方案。

问题出在第二个问题c：when和c：foreach。我这样做了：

<c:choose>
  <c:when test="${not empty requestScope['nameList'] }">
    <c:forEach var="name" items="${requestScope[' nameList '] }">
      Name:${name.name }
        <c:choose>
          <c:when test="${not empty requestScope[' nameList.phoneList'] }">
            <c:forEach var="phone" items="${requestScope ['nameList.phoneList'] }">
              Phone:${phone.phone } </div>
            </c:forEach>
          </c:when>
          <c:otherwise>
         <span>The phone list is empty.</span>
          </c:otherwise>
      </c:choose>
    </c:forEach>
  </c:when>
</c:choose>

我替换它们：

<c:choose>
  <c:when test="${not empty requestScope['nameList'] }">
    <c:forEach var="name" items="${requestScope[' nameList '] }">
      Name:${name.name }
        <c:choose>
          <c:when test="${not empty nameList.phoneList }">
            <c:forEach var="phone" items="${nameList.phoneList }">
              Phone:${phone.phone } </div>
            </c:forEach>
          </c:when>
          <c:otherwise>
         <span>The phone list is empty.</span>
          </c:otherwise>
      </c:choose>
    </c:forEach>
  </c:when>
</c:choose>

phoneList位于我在请求中建立的nameList的每个名称对象中。当我循环nameList时，我可以使用表达式访问phoneList：

${nameList.phoneList}

我希望我的英语是正确的。

如何将复杂对象发送到jsp

2 个答案: