HTTP 状态 500 没有属性“id”答案

【问题标题】：HTTP Status 500 does not have the property 'id'HTTP 状态 500 没有属性“id”
【发布时间】：2019-10-24 19:43:27
【问题描述】：

我在显示客户 ID 时收到错误消息。我也曾尝试更改属性“id”的名称，但新名称出现了同样的错误。

HTTP 状态 500 - 内部服务器错误

类型异常报告消息内部服务器错误说明服务器遇到了一个内部错误，导致它无法完成此请求。

例外 org.apache.jasper.JasperException: javax.el.PropertyNotFoundException: 类 'de.java2enterprise.onlineshop.model.Customer' 没有属性 'id'。

根本原因 javax.el.PropertyNotFoundException：类“de.java2enterprise.onlineshop.model.Customer”没有属性“id”。

注意GlassFish Server Open Source Edition 5.1.0 日志中提供了异常的完整堆栈跟踪及其根本原因。

HTML：

<%@ include file="header.jspf" %>

<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title>Onlineshop</title>
	</head>
	<body>
		

<c:forEach var="customer" items="${customers}">
<article>
	<p>${customer.id}</p>
	<p>${customer.email}</p>
	<p>test</p>
</article>
</c:forEach>

<%@ include file="footer.jspf" %>

Java 类

包 de.java2enterprise.onlineshop.model;

导入 java.io.Serializable;

公共类客户实现可序列化{ private static final long serialVersionUID = 1L;

private Long id;
private String email;
private String password;

public Customer() {}

public Customer(String email, String password) {
    this.email = email;
    this.password = password;
}

public Long getID() {
    return id;
}

public void setID(Long id) {
    this.id = id;
}

public String getEmail() {
    return email;
}

public void setEmail(String email) {
    this.email = email;
}

public String getPassword() {
    return password;
}

public void setPassword(String password) {
    this.password = password;
}

public String toString() {
    return 
        "[" +
        getID() + ", " +
        getEmail() + ", " +
        getPassword() + 
        "]";
}

}

控制器

@WebServlet("/userShow")

公共类 UserServlet 扩展 HttpServlet { private static final long serialVersionUID = 1L;

@Resource
private DataSource ds;
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    doPost(request, response);
}
public void doPost( HttpServletRequest request,  HttpServletResponse response) throws ServletException, IOException {

    try {
        List<Customer> customers = find();
        if (customers != null) {
            HttpSession session = request.getSession();
            session.setAttribute("customers", customers);
        }
    } catch (Exception e) {
        throw new ServletException(e.getMessage());
    }
    RequestDispatcher dispatcher = request.getRequestDispatcher("search.jsp");
    dispatcher.forward(request, response);
}

public List<Customer> find() throws Exception {

    List<Customer> customers = new ArrayList<Customer>();
    try (final Connection con = ds.getConnection();
            final PreparedStatement stmt = con
                    .prepareStatement(
                            "SELECT " +
                                    "id, " +
                                    "email, " +
                                    "password " +
                                    "FROM onlineshop.customer ")) {
        ResultSet rs = stmt.executeQuery();
        while (rs.next()) {

客户 customer = new Customer();

            Long id = Long.valueOf(rs.getLong("id"));
            customer.setID(id);

            String email = rs.getString("email");
            customer.setEmail(email);

            String password = rs.getString("password");
            customer.setPassword(password);
            customers.add(customer);

        }
    }
    return customers;
}

}

【问题讨论】：

看起来您没有一个名为 id 的属性，而是一个名为 ID 的属性。

标签： java

【解决方案1】：

您的 Customer 类需要遵循 Java bean 的命名约定：

它是getId/setId 而不是getID/setID。

【讨论】：