Java Web程序设计第9章课后第1题

1. 编写图书模糊查询界面，输入图书名称的模糊资料，在界面下方显示图书信息，要求提交给Servlet完成。

在数据库中建个表

然后简单地弄一个book类

public class book {
    public String id;
    public String name;
    public double price;

    public book(String id, String name, double price) {
        this.id = id;
        this.name = name;
        this.price = price;
    }
}

在search.jsp中先搭个框架

    请输入要查找的书名：
    


    

        
图书ID
        
图书名称
        
图书价格
        
操作
    
    

新建一个FuzzyLookupServlet

@WebServlet(name = "FuzzyLookupServlet", urlPatterns = {"/fuzzyLookupServlet"})
public class FuzzyLookupServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // 处理响应乱码
        response.setContentType("text/html;charset=utf-8");

        // 处理请求乱码
        request.setCharacterEncoding("utf-8");

        String name = request.getParameter("name");
        if (name != null) {
            try {
                // 1、导入驱动jar包
                // 2、注册驱动
                Class.forName("com.mysql.cj.jdbc.Driver");
                // 3、获取数据库的连接对象
                Connection conn = DriverManager.getConnection("你的数据库", "用户名", "你的密码");
                // 4、定义sql语句
                String sql = "select * from book where name like '%" + name + "%'";
                // 5、获取执行sql语句的对象
                PreparedStatement ps = conn.prepareStatement(sql);
                // 6、执行sql并接收返回结果
                ResultSet rs = ps.executeQuery(sql);
                // 7、处理结果
                ArrayList res = new ArrayList();
                while (rs.next()) {
                    res.add(new book(rs.getString(1), rs.getString(2), rs.getDouble(3)));
                }
                HttpSession session = request.getSession();
                session.setAttribute("result", res);  // 把查询到的结果存放在session中
                // 8、释放资源
                ps.close();
                conn.close();
                // 9、跳转
                request.getRequestDispatcher("/chapter9/9_1/search.jsp").forward(request, response);  // 查询完毕后要返回到search.jsp
            } catch (ClassNotFoundException | SQLException e) {
                e.printStackTrace();
            }
        }
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doPost(request, response);
    }
}

回到search.jsp，先把form action补齐，如

然后补全JSP代码

<%
    ArrayList res = (ArrayList) session.getAttribute("result");
    if (res != null) {
%>

    <%
            for (book b : res) {
                out.print("");
                out.print("");
                out.print("");
                out.print("");
                out.print(String.format("", b.id));
                out.print("");
            }
        }
    %>
 
完整代码 
search.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ page import="chapter9.book" %>
<%@ page import="java.util.ArrayList" %>


    



    请输入要查找的书名：
    

<%
    ArrayList res = (ArrayList) session.getAttribute("result");
    if (res != null) {
%>

    

        
图书ID
        
图书名称
        
图书价格
        
操作
    
" + b.id + "
" + b.name + "
" + b.price + "
添加到购物车
 

    <%
            for (book b : res) {
                out.print("");
                out.print("");
                out.print("");
                out.print("");
                out.print(String.format("", b.id));
                out.print("");
            }
        }
    %>

    

        
图书ID
        
图书名称
        
图书价格
        
操作
    
" + b.id + "
" + b.name + "
" + b.price + "
添加到购物车

FuzzyLookupServlet.java

package chapter9.servlet;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;
import java.sql.*;
import java.util.ArrayList;

import chapter9.book;

import static java.lang.System.out;

@WebServlet(name = "FuzzyLookupServlet", urlPatterns = {"/fuzzyLookupServlet"})
public class FuzzyLookupServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // 处理响应乱码
        response.setContentType("text/html;charset=utf-8");

        // 处理请求乱码
        request.setCharacterEncoding("utf-8");

        String name = request.getParameter("name");
        if (name != null) {
            try {
                // 1、导入驱动jar包
                // 2、注册驱动
                Class.forName("com.mysql.cj.jdbc.Driver");
                // 3、获取数据库的连接对象
                Connection conn = DriverManager.getConnection("你的数据库", "用户名", "你的密码");
                // 4、定义sql语句
                String sql = "select * from book where name like '%" + name + "%'";
                // 5、获取执行sql语句的对象
                PreparedStatement ps = conn.prepareStatement(sql);
                // 6、执行sql并接收返回结果
                ResultSet rs = ps.executeQuery(sql);
                // 7、处理结果
                ArrayList res = new ArrayList();
                while (rs.next()) {
                    res.add(new book(rs.getString(1), rs.getString(2), rs.getDouble(3)));
                }
                HttpSession session = request.getSession();
                session.setAttribute("result", res);
                // 8、释放资源
                ps.close();
                conn.close();
                // 9、跳转
                request.getRequestDispatcher("/chapter9/9_1/search.jsp").forward(request, response);
            } catch (ClassNotFoundException | SQLException e) {
                e.printStackTrace();
            }
        }
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doPost(request, response);
    }
}

book.java

package chapter9;

public class book {
    public String id;
    public String name;
    public double price;

    public book(String id, String name, double price) {
        this.id = id;
        this.name = name;
        this.price = price;
    }
}