JavaWeb项目【源码】——图书项目1.0：Tomcat版本 + Servlet + Filter + Jsp + bootstrap & JavaScript初步 + Ajax初步

由于原始代码已经是一个较为完整的JavaWeb项目，下面我们提取核心代码来回答这个问题。

1. web.xml配置文件：

<web-app ...>
    <filter>
        <filter-name>EncodingFilter</filter-name>
        <filter-class>com.example.book.filter.EncodingFilter</filter-class>
        <init-param>
            <param-name>charset</param-name>
            <param-value>UTF-8</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>EncodingFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
 
    <servlet>
        <servlet-name>BookServlet</servlet-name>
        <servlet-class>com.example.book.servlet.BookServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>BookServlet</servlet-name>
        <url-pattern>/book</url-pattern>
    </servlet-mapping>
</web-app>

2. EncodingFilter类：

package com.example.book.filter;
 
import javax.servlet.*;
import java.io.IOException;
 
public class EncodingFilter implements Filter {
    private String charset;
 
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        charset = filterConfig.getInitParameter("charset");
    }
 
    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
            throws IOException, ServletException {
        request.setCharacterEncoding(charset);
        response.setContentType("text/html; charset=" + charset);
        chain.doFilter(request, response);
    }
 
    @Override
    public void destroy() {
        // 空实现
    }
}

3. BookServlet类：

package com.example.book.servlet;
 
import com.example.book.dao.BookDAO;
import com.example.book.dao.impl.BookDAOImpl;
import com.example.book.model.Book;
 
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.IOException;
import java.util.List;
 
public class BookServlet extends HttpServlet {
    private BookDAO bookDAO = new BookDAOImpl();
 
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        List<Book> books = bookDAO.findAll();
        request.setAttribute("books", books);
        request.getRequestDispatche