Я пытаюсь перенести данные из Mysql в Jsp (используя Tomcat Server), но я не могу получить данные, и мой код не показывает ошибок.
Когда я запускаю его как приложение Java, я вижу данные mysql с моего контроллера. Я буду рад, если вы сможете помочь в этом вопросе.
Вы можете посмотреть мою базу данных здесь
https://ibb.co/iauGYn
Модель класса
public class Book{
protected int id;
protected String title;
protected String author;
protected float price;
public Book() {
}
public Book(int id) {
this.id = id;
}
public Book(int id, String title, String author, float price) {
this(title, author, price);
this.id = id;
}
public Book(String title, String author, float price) {
this.title = title;
this.author = author;
this.price = price;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public String getAuthor() {
return author;
}
public void setAuthor(String author) {
this.author = author;
}
public float getPrice() {
return price;
}
public void setPrice(float price) {
this.price = price;
}
Просмотр Jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<html>
<head>
<title>Books Store Application</title>
</head>
<body>
<div align="center">
<table border="1" cellpadding="5">
<caption><h2>List of Books</h2></caption>
<tr>
<th>ID</th>
<th>Title</th>
<th>Author</th>
<th>Price</th>
<th>Actions</th>
</tr>
<c:forEach var="book" items="${listBook}">
<tr>
<td><c:out value="${book.id}" /></td>
<td><c:out value="${book.title}" /></td>
<td><c:out value="${book.author}" /></td>
<td><c:out value="${book.price}" /></td>
<td>
<a href="/edit?id=<c:out value='${book.id}' />">Edit</a>
<a href="/delete?id=<c:out value='${book.id}' />">Delete</a>
</td>
</tr>
</c:forEach>
</table>
</div>
</body>
</html>
Класс BookDAO для операций с БД
public class BookDAO {
private String jdbcURL;
private String jdbcUsername;
private String jdbcPassword;
private Connection jdbcConnection;
public BookDAO(String jdbcURL, String jdbcUsername, String jdbcPassword) {
this.jdbcURL = jdbcURL;
this.jdbcUsername = jdbcUsername;
this.jdbcPassword = jdbcPassword;
}
protected void connect() throws SQLException {
if (jdbcConnection == null || jdbcConnection.isClosed()) {
try {
Class.forName("com.mysql.jdbc.Driver");
} catch (ClassNotFoundException e) {
throw new SQLException(e);
}
jdbcConnection = DriverManager.getConnection(
jdbcURL, jdbcUsername, jdbcPassword);
}
}
protected void disconnect() throws SQLException {
if (jdbcConnection != null && !jdbcConnection.isClosed()) {
jdbcConnection.close();
}
}
public List<Book> listAllBooks() throws SQLException {
List<Book> listBook = new ArrayList<>();
String sql = "SELECT * FROM book";
connect();
Statement statement = jdbcConnection.createStatement();
ResultSet resultSet = statement.executeQuery(sql);
while (resultSet.next()) {
int id = resultSet.getInt("id");
String title = resultSet.getString("title");
String author = resultSet.getString("author");
float price = resultSet.getFloat("price");
Book book = new Book(id, title, author, price);
listBook.add(book);
}
resultSet.close();
statement.close();
disconnect();
return listBook;
}
public Book getBook(int id) throws SQLException {
Book book = null;
String sql = "SELECT * FROM book WHERE id = ?";
connect();
PreparedStatement statement = jdbcConnection.prepareStatement(sql);
statement.setInt(1, id);
ResultSet resultSet = statement.executeQuery();
if (resultSet.next()) {
String title = resultSet.getString("title");
String author = resultSet.getString("author");
float price = resultSet.getFloat("price");
book = new Book(id, title, author, price);
}
resultSet.close();
statement.close();
return book;
}
Класс контроллера.
public class BookController extends HttpServlet {
private static final long serialVersionUID = 1L;
private BookDAO bookDAO;
public void init() {
String jdbcURL = getServletContext().getInitParameter("jdbc:mysql://localhost:3306/bookstore");
String jdbcUsername = getServletContext().getInitParameter("root");
String jdbcPassword = getServletContext().getInitParameter("root");
bookDAO = new BookDAO(jdbcURL, jdbcUsername, jdbcPassword);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String action = request.getServletPath();
listBook(request, response);
}
private void listBook(HttpServletRequest request, HttpServletResponse response)
{
List<Book> listBook = null;
try {
listBook = bookDAO.listAllBooks();
} catch (SQLException e) {
e.printStackTrace();
}
request.setAttribute("listBook", listBook);
RequestDispatcher dispatcher = request.getRequestDispatcher("BookList.jsp");
try {
dispatcher.forward(request, response);
} catch (ServletException | IOException e) {
e.printStackTrace();
}
}
private void showNewForm(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
RequestDispatcher dispatcher = request.getRequestDispatcher("BookForm.jsp");
dispatcher.forward(request, response);
}
private void showEditForm(HttpServletRequest request, HttpServletResponse response)
throws SQLException, ServletException, IOException {
int id = Integer.parseInt(request.getParameter("id"));
Book existingBook = bookDAO.getBook(id);
RequestDispatcher dispatcher = request.getRequestDispatcher("BookForm.jsp");
request.setAttribute("book", existingBook);
dispatcher.forward(request, response);
}