图书信息查询系统

package top.gaojc.action;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import top.gaojc.bean.Book;
import top.gaojc.test.BookTest;

public class BookSearchServlet extends HttpServlet {

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

  public void doPost(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {
    
    // 1.设置编码
    request.setCharacterEncoding("utf-8");
    
    // 2.获取参数
    String bookName = request.getParameter("bookName");
    Book book = BookTest.getBookByName(bookName);
        
    // 3.将图书信息显示在bookInfo.jsp的页面
    request.setAttribute("book", book);
    request.getRequestDispatcher("bookInfo.jsp").forward(request, response);
  }
}

package top.gaojc.bean;

public class Book {
  
  private int id;
  private String bookName;
  private String author;
  private String classify;
  private float price;
  
  public int getId() {
    return id;
  }
  public void setId(int id) {
    this.id = id;
  }
  public String getBookName() {
    return bookName;
  }
  public void setBookName(String bookName) {
    this.bookName = bookName;
  }
  public String getAuthor() {
    return author;
  }
  public void setAuthor(String author) {
    this.author = author;
  }
  public String getClassify() {
    return classify;
  }
  public void setClassify(String classify) {
    this.classify = classify;
  }
  public float getPrice() {
    return price;
  }
  public void setPrice(float price) {
    this.price = price;
  }
  
  public Book() {
    super();
    // TODO Auto-generated constructor stub
  }
  
  public Book(int id, String bookName, String author, String classify,
      float price) {
    super();
    this.id = id;
    this.bookName = bookName;
    this.author = author;
    this.classify = classify;
    this.price = price;
  }
  
  @Override
  public String toString() {
    return "<tr>"
        +"<td><center>"+id+"</center></td>"
        +"<td><center>"+bookName+"</center></td>"
        +"<td><center>"+author+"</center></td>"
        +"<td><center>"+classify+"</center></td>"
        +"<td><center>"+price+"</center></td>"
      +"</tr>";
  }
}

package top.gaojc.test;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;

import top.gaojc.bean.Book;
import top.gaojc.util.DBUtil;

public class BookTest {
  public static Book getBookByName(String bookName) {
    // 连接数据库并且把数据查询出来 存储在book对象中，最后返回book对象即可

    // 1 2 调用DBUtil方法添加驱动程序包、连接数据库
    Connection conn = DBUtil.getConn();

    // 3.添加sql语句
    String sql = "select * from book where bookName = ?";

    // 4.准备一个和数据库打交道的
    PreparedStatement ps = null;
    ResultSet rs = null;
    Book book = null;
    try {
      ps = conn.prepareStatement(sql);
      ps.setString(1, bookName);
      // 5.查询结果
      rs = ps.executeQuery();
      if (rs.next()) {
        // 创建一个有属性值的对象
        // 6.输出
        book = new Book(rs.getInt(1), rs.getString(2), rs.getString(3),rs.getString(4), rs.getFloat(5));
      }
    } catch (Exception e) {
      // TODO: handle exception
    } finally {
      // 7.调用DBUtil关闭资源
      DBUtil.close(conn, ps, rs);
    }
    // 返回值
    return book;
  }
}

package top.gaojc.util;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class DBUtil {
  
  // 1.添加驱动程序包
  static {
    try {
      Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
    } catch (ClassNotFoundException e) {
      e.printStackTrace();
    }
  }

  // 2.连接数据库
  public static Connection getConn() {
    Connection conn = null;
    try {
      // ("jdbc:运行环境://localhost:端口号;databaseName=数据库名称","SQL账号","SQL密码")
      conn = DriverManager.getConnection("jdbc:sqlserver://localhost:1433;databaseName=bookwork","sa", "1");
    } catch (SQLException e) {
      e.printStackTrace();
    }
    return conn;
  }

  // 7.关闭资源
  public static void close(Connection conn, PreparedStatement ps, ResultSet rs) {
    try {
      if (conn != null)
        conn.close();

      if (ps != null)
        ps.close();

      if (rs != null)
        rs.close();
    } catch (SQLException e) {
      e.printStackTrace();
    }
  }
}

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" 
  xmlns="http://java.sun.com/xml/ns/javaee" 
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
  xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
  http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
  <display-name></display-name>
  <servlet>
    <description>This is the description of my J2EE component</description>
    <display-name>This is the display name of my J2EE component</display-name>
    <servlet-name>BookSearchServlet</servlet-name>
    <servlet-class>top.gaojc.action.BookSearchServlet</servlet-class>
  </servlet>

  <servlet-mapping>
    <servlet-name>BookSearchServlet</servlet-name>
    <url-pattern>/BookSearchServlet</url-pattern>
  </servlet-mapping>  
  <welcome-file-list>
    <welcome-file>search.jsp</welcome-file>
  </welcome-file-list>
</web-app>

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
  String path = request.getContextPath();
  String basePath = request.getScheme() + "://"
      + request.getServerName() + ":" + request.getServerPort()
      + path + "/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">

<title>My JSP 'index.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
  <link rel="stylesheet" type="text/css" href="styles.css">
  -->
</head>

<body>
  <form action="BookSearchServlet" method="post">
    图书名称：
    <input type="text" name="bookName">
    <input type="submit"value="查询">
  </form>
</body>
</html>

<%@page import="top.gaojc.bean.Book"%>
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
  String path = request.getContextPath();
  String basePath = request.getScheme() + "://"
      + request.getServerName() + ":" + request.getServerPort()
      + path + "/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">

<title>My JSP 'index.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
  <link rel="stylesheet" type="text/css" href="styles.css">
  -->
</head>

<body>
  <%
    // 接收Book值
    Book book = (Book) request.getAttribute("book");
  %>

  <h1 style=text-align:center;>查询结果</h1>
  <table border="1" cellpadding="0" cellspacing="0" align="center" width="600px">
    <tr>
      <td><center>编号</center></td>
      <td><center>图书名称</center></td>
      <td><center>作者</center></center></td>
      <td><center>类别</center></td>
      <td><center>价格</center></td>
    </tr>
    
    <%
      if (book != null) {
        // 如果book的值不是空值 打印出来图书信息
        out.println(book.toString() + "<br>");
      } else {
        // 如果为空值的话继续跳转到search.jsp页面
        request.getRequestDispatcher("search.jsp").forward(request,response);
      }
    %>
  </table>
</body>
</html>