如何在jsp中填充组合框? [英] how to fill combobox in jsp?

问题描述

我尝试了，这是我的尝试.请帮助我 我需要从数据库中的jsp中填充组合框

I tried and this is my attempt Please help me i need to fill combobox in jsp from my database

1-jsp页面

       <p class="ppp">Category</p>
<jsp:useBean id="categorys" class="database.conDB" scope="page"/>
<select name="categorys" size="1" style="width:196px; padding:5px;" >
<c:forEach var="categ" items="${categorys.categoryNames} ">
 <option value="${categ}">${categ} </option>
 </c:forEach>  
</select>

============ 2-这是我在conDB类中的功能

=========== 2-this my function in conDB class

    public String[] getCategory()
{
    String query="SELECT category_name FROM books.category;";
    Statement statement;
    ResultSet resultSet ;
    try{
        statement=createConnection().createStatement();
        resultSet=statement.executeQuery(query);
        int count=0;
        while(resultSet.next())
                count++;
        categoryNames=new String[count];
        resultSet.first();
        do{
            categoryNames[count -1]=resultSet.getString("category_name");
            count--;

        }while(resultSet.next());


    }catch(Exception e)
    {e.printStackTrace();}
    for (int i = categoryNames.length; i > 0; i--)
        System.out.println(categoryNames[i - 1]);
    return categoryNames;
    }

推荐答案

您必须将selected属性添加到要选择的<option>标签中.

You have to add the selected attribute to the <option> tag you want to select.

例如:

<option value="${categ}" ${ <<selected condition>> ? 'selected' : ''>${categ}</option>

<<selected condition>>是用于确定是否应选择类别的条件.例如.如果要始终选择名为house的类别，则为:categ == 'house'

<<selected condition>> is the condition that is used to determine if the category should be selected. E.g. If you want to always select the category named house it would be: categ == 'house'

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