試圖從 mySQL 數據庫中獲取結果並將其顯示在 jsp 文件中
[英]Trying to fetch results from mySQL database and display it in a jsp file
問題描述
使用 MVC model 嘗試從 mySQL 數據庫中獲取。 該代碼嘗試查詢db並將結果放入and數組以將其傳遞給controller。然后jsp頁面可以調用它。 目前，即使它可以編譯，我也沒有顯示結果
看法
public class ViewQA {
public static void main(String category, String questions, String answers) {
// TODO Auto-generated constructor stub
}
public static List<ViewQA> listData() throws SQLException, ClassNotFoundException {
List<ViewQA> listData = new ArrayList<>();
try (java.sql.Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/examgenappschema",
"EXadmin", "abc123");) {
PreparedStatement select = null;
String queryString = ("SELECT category, questions, answers FROM examgen");
select = conn.prepareStatement(queryString);
ResultSet rs = select.getResultSet();
while (rs.next()) {
rs.getString("category");
rs.getString("questions");
rs.getString("answers");
ViewQA results = new ViewQA();
listData.add(results);
}
}
return listData;
}
}
Controller
@Controller
public class ExamGenController {
@RequestMapping(value = "/examgen", method = RequestMethod.GET)
public String DataArray(@ModelAttribute("listData") ViewQA listData, ModelMap model)
throws ClassNotFoundException, SQLException {
return "examgen";
}}
jsp 頁
<!DOCTYPE html>
<html>
<body>
<center>
<h1>List of Questions and Answers</h1>
</center>
<div align="center">
<table border="1" cellpadding="3">
<tr>
<th>category</th>
<th>questions</th>
<th>answers</th>
</tr><c:forEach var="listData" items="${DataArray}">
<div class="grid-item4"> ${DataArray.category} </div>
<div class="grid-item4"> ${DataArray.questions} </div>
<div class="grid-item4"> ${DataArray.answers} </div>
</c:forEach>
</table>
</div>
</body>
</html>
2 個解決方案
解決方案1
0 2022-10-05 10:00:07
您忘記將查詢結果添加到ViewQA 。 您將空白 ViewQA object 添加到列表中。
解決方案2
0 2022-10-10 09:42:11
您正在使用 var 但未在代碼中使用它，請嘗試這種方式。
<c:forEach var="listData" items="${DataArray}">
<div class="grid-item4"> ${listData.category} </div>
<div class="grid-item4"> ${listData.questions} </div>
<div class="grid-item4"> ${listData.answers} </div>
無法使用JSP從MySQL數據庫獲取數據
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