Question

我正在尝试在Struts2上构建一个向数据库表添加值的页面。问题是，页面必须允许用户向数据库表输入多行。当用户单击“提交”时，它必须读取和写入数据库表的行。用户可以在页面中添加或删除行

因此我尝试在页面上呈现List值。 Java代码如下所示：

List<Testimate> estimates;
private String removeIndex;

public String execute() throws Exception {
    estimates = new ArrayList<Testimate>();
    for(int i = 0; i < INITIAL_ESTIMATES; i++)
        estimates.add(new Testimate());
    return INPUT;
}
public String add() {
    estimates.add(new Testimate());
    System.out.println(estimates.size());
    return INPUT;
}

public String remove() {
    estimates.remove(Integer.parseInt(getRemoveIndex()));
    System.out.println(estimates.size() + " " + getRemoveIndex());


    return INPUT;
    }

And the page looks something like this:

<script>
   setRemoveIndex()
   {    
        $('input[name="removeIndex"]').val(removeIndex);
        return true;
   }
</script>
<s:form theme="custom" onsubmit="setRemoveIndex()">
<s:submit action="CEST02_add" cssClass="ButtonSmall" value="Add estimate" />
<s:hidden name="removeIndex"/>
<table>
<s:iterator value="estimates" var="estimate" status="status">
<tr>
   <td><s:textfield name="estimates[%{#status.index}].name"cssClass="product" /></td>
   <td><s:textfield name="estimates[%{#status.index}].price"cssClass="product" /></td>
   <td><s:textfield name="estimates[%{#status.index}].date"cssClass="product" /></td>
   <td><s:textfield name="estimates[%{#status.index}].attr"cssClass="product" /></td>
   <td><s:submit action="CEST02_remove" cssClass="ButtonSmall" value="Remove this estimate" onclick="removeIndex=%{#status.index}"/>
   </td>
</tr>
</s:iterator>
</table>
</s:form>

当我点击“添加估计”时，它会将元素添加到“估计”列表中。并且它正确打印尺寸。但是，当我点击“删除此估算值”时，它不会更改“估算值”列表。但它打印出列表的大小减少了一个。当我再次点击时，大小根本不会改变。它没有得到任何修改。

请告诉我这段代码有什么问题。我可能会对这个框架的运作方式产生一些误解。如果您有任何问题或说明，请直接询问

更新

我在JSP上使用以下行解决了我的问题。但问题仍然是为什么我不能在我的行动中做到这一点。

<s:iterator value="estimates" var="estimate" status="status">
   <s:if test="#status.index != removeIndex">

Answer 1

我尝试使用你的代码并且它对我来说很好。虽然我不理解你Testimate课程的内部，所以取代List<Testimate> estimates我List<String> estimates;。这是我的工作代码。

行动类

List<String> estimates;
private int removeIndex;
//there getters and setters

public String execute() throws Exception
    {

        estimates = new ArrayList<String>();
        for(int i = 0; i < 5; i++){
            estimates.add(""+i);
        }
        return SUCCESS;
    }

    public String remove() {
        estimates.remove(getRemoveIndex());
        System.out.println(estimates.size() + " " + getRemoveIndex());
        return SUCCESS;
        }

JSP

<body>
  <script>
  function setRemoveIndex(val)
   {    
       alert(val);
       document.getElementById("removeIndex").value=val;
       //$('input[name="removeIndex"]').val(removeIndex);
       document.myform.action="remove.action";
       document.myform.submit();
        return true;
   }
</script>
<s:form theme="simple" id="myform" name="myform">
<s:submit action="CEST02_add" cssClass="ButtonSmall" value="Add estimate" />
<s:hidden name="removeIndex" id="removeIndex"/>
<table>
<s:iterator value="estimates" var="estimate" status="status">
<tr>
   <td><s:textfield name="estimates[%{#status.index}]"cssClass="product" /></td>
   <td>
   <s:submit action="remove" cssClass="ButtonSmall" value="Remove this estimate" onclick="return setRemoveIndex('%{#status.index}')"/>
   </td>
</tr>
</s:iterator>
</table>
</s:form>
</body>

struts.xml中

 <action name="remove" class="example.HelloWorld" method="remove">
     <result>/example/HelloWorld.jsp</result>
 </action>

以上代码完全删除了List值，我也检查了页面刷新，并且值没有回来。

Answer 2

您是否尝试在删除项目后在remove（）中刷新Hibernate会话？我认为您的更改未被提交。

Answer 3

请参阅以下代码，该代码对我有用：

行动类

package com.mycompany;

import com.opensymphony.xwork2.ActionSupport;
import java.util.ArrayList;
import java.util.List;

/**
 *
 * @author james
 */
public class EstimateAction extends ActionSupport {

    private List<Testimate> estimates;
    private String removeIndex;
    private static final int INITIAL_ESTIMATES = 10;

    public List<Testimate> getEstimates() {
        return estimates;
    }

    public void setEstimates(List<Testimate> estimates) {
        this.estimates = estimates;
    }

    public String getRemoveIndex() {
        return removeIndex;
    }

    public void setRemoveIndex(String removeIndex) {
        this.removeIndex = removeIndex;
    }

    public String execute() throws Exception {
        estimates = new ArrayList<Testimate>();
        for (int i = 0; i < INITIAL_ESTIMATES; i++) {
            estimates.add(new Testimate());
        }
        return INPUT;
    }

    public String add() {
        estimates.add(new Testimate());
        System.out.println(estimates.size());
        return INPUT;
    }

    public String remove() {
        estimates.remove(Integer.parseInt(getRemoveIndex()));
        System.out.println(estimates.size() + " " + getRemoveIndex());


        return INPUT;
    }
}

<强> struts.xml中

<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
"http://struts.apache.org/dtds/struts-2.0.dtd">

<struts>
    <!-- Configuration for the default package. -->
    <constant name="struts.devMode" value="true" />
    <package name="default" extends="struts-default">
        <action name="showEstimates" class="com.mycompany.EstimateAction">
            <result name="input">/estimatePage.jsp</result>
        </action>
        <action name="removeEstimates" class="com.mycompany.EstimateAction" method="remove">
            <result name="input">/estimatePage.jsp</result>
        </action>
    </package>
</struts>

<强> estimatePage.jsp

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
    "http://www.w3.org/TR/html4/loose.dtd">
<%@taglib uri="/struts-tags" prefix="s" %>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>JSP Page</title>
        <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/jquery.min.js"></script>
        <script type="text/javascript">
            function setRemoveIndex(removeIndex)
            {
                document.myForm.action = "removeEstimates.action";    //First set the form to navigate to the specific action
                $('input[name="removeIndex"]').val(removeIndex);
                //alert("Here");
                document.myForm.submit();                             //Submit the form with the action attribute change
                return false;                                         //Cancel the form submission which was triggered earlier
            }
        </script>
    </head>
    <body>
        <s:form name="myForm" onsubmit="setRemoveIndex()">
            <s:submit action="add" cssClass="ButtonSmall" value="Add estimate" />
            <s:hidden name="removeIndex"/>
            <table>
                <s:iterator value="estimates" var="estimate" status="status">
                    <tr>
                        <td><s:textfield name="estimates[%{#status.index}].name"cssClass="product" /></td>
                        <td><s:textfield name="estimates[%{#status.index}].price"cssClass="product" /></td>
                        <td><s:textfield name="estimates[%{#status.index}].date"cssClass="product" /></td>
                        <td><s:textfield name="estimates[%{#status.index}].attr"cssClass="product" /></td>
                        <td><s:submit action="remove" cssClass="ButtonSmall" value="Remove this estimate" onclick="return setRemoveIndex(%{#status.index})"/>
                        </td>
                    </tr>
                </s:iterator>
            </table>
        </s:form>
    </body>
</html>

Struts2动态添加，从页面中删除对象列表

3 个答案:

行动类

JSP

struts.xml中