因此，我试图使用此servlet从我的SQL表中获取一些数据，并将其输出到JSP文件中。我发现了一些有类似问题的文章，但对我而言，这些文章都没有帮助。我希望这里有人可以帮助我。
我必须为我的一个班级做这个项目。我基本上是在为网上服装店编程。例如，如果我单击T恤，则我希望此代码将在sql表“ T恤”下可以找到的所有数据放到JSP文件中。
从我从其他人的错误中学到的是，我的SQL查询是错误的。但是我不明白为什么我在调用方法display（）时将第39行标记为false。
所以这是我的代码：
@WebServlet("/DisplayClothes")
public class DisplayClothes extends HttpServlet {
private static final long serialVersionUID = 1L;
public DisplayClothes() {
super();
}
@Resource(lookup = "java:jboss/datasources/MySqlThidbDS")
private DataSource ds;
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
List<Clothes> Clothes= display();
HttpSession session = request.getSession();
session.setAttribute("Clothes", Clothes);
final RequestDispatcher dispatcher = request.getRequestDispatcher("./JSP/ViewColthing.jsp");
dispatcher.forward(request, response);
}
public List<Clothes> display() throws ServletException{
List<Clothes> cl = new ArrayList<Clothes>();
try (Connection con = ds.getConnection();
PreparedStatement pstmt = con.prepareStatement("SELECT * FROM clothes")) {
pstmt.setInt(1, 1);
try (ResultSet rs = pstmt.executeQuery()) {
while (rs.next()) {
Clothes clothes= new Clothes();
clothes.setId(Long.valueOf(rs.getInt("id")));
clothes.setName(rs.getString("name"));
clothes.setDes(rs.getString("description"));
clothes.price(rs.getFloat("preis"));
clothes.setSize(rs.getString("sizes"));
clothes.setQuantity(rs.getInt("quantity"));
cl.add(Clothes);
}
}
} catch (Exception ex) {
throw new ServletException(ex.getMessage());
}
return cl;
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
}
并且我收到此错误消息。
javax.servlet.ServletException: Parameter index out of range (1 > number of parameters, which is 0).
at Servlets.DisplayClothes.display(DisplayClothes.java:76)
at Servlets.DisplayClothes.doGet(DisplayClothes.java:39)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:503)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:590)
at io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:74)
at io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:62)
at io.undertow.servlet.handlers.ServletChain$1.handleRequest(ServletChain.java:68)
at io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36)
at org.wildfly.extension.undertow.security.SecurityContextAssociationHandler.handleRequest(SecurityContextAssociationHandler.java:78)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.servlet.handlers.RedirectDirHandler.handleRequest(RedirectDirHandler.java:68)
at io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:132)
at io.undertow.servlet.handlers.security.ServletAuthenticationCallHandler.handleRequest(ServletAuthenticationCallHandler.java:57)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:46)
at io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:64)
at io.undertow.security.handlers.AuthenticationMechanismsHandler.handleRequest(AuthenticationMechanismsHandler.java:60)
at io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:77)
at io.undertow.security.handlers.NotificationReceiverHandler.handleRequest(NotificationReceiverHandler.java:50)
at io.undertow.security.handlers.AbstractSecurityContextAssociationHandler.handleRequest(AbstractSecurityContextAssociationHandler.java:43)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at org.wildfly.extension.undertow.security.jacc.JACCContextIdHandler.handleRequest(JACCContextIdHandler.java:61)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at org.wildfly.extension.undertow.deployment.GlobalRequestControllerHandler.handleRequest(GlobalRequestControllerHandler.java:68)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:269)
at io.undertow.servlet.handlers.ServletInitialHandler.access$100(ServletInitialHandler.java:78)
at io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:133)
at io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:130)
at io.undertow.servlet.core.ServletRequestContextThreadSetupAction$1.call(ServletRequestContextThreadSetupAction.java:48)
at io.undertow.servlet.core.ContextClassLoaderSetupAction$1.call(ContextClassLoaderSetupAction.java:43)
at org.wildfly.extension.undertow.security.SecurityContextThreadSetupAction.lambda$create$0(SecurityContextThreadSetupAction.java:105)
at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1504)
at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1504)
at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1504)
at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1504)
at io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:249)
at io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:78)
at io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:99)
at io.undertow.server.Connectors.executeRootHandler(Connectors.java:376)
at io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:830)
at org.jboss.threads.ContextClassLoaderSavingRunnable.run(ContextClassLoaderSavingRunnable.java:35)
at org.jboss.threads.EnhancedQueueExecutor.safeRun(EnhancedQueueExecutor.java:1982)
at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.doRunTask(EnhancedQueueExecutor.java:1486)
at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.run(EnhancedQueueExecutor.java:1377)
at java.lang.Thread.run(Thread.java:748)
查询中没有绑定参数。删除
pstmt.setInt(1, 1);
没有任何设置。另外，
cl.add(Clothes);
应该是
cl.add(clothes);