jsp+servlet+jdbc實(shí)現(xiàn)對(duì)數(shù)據(jù)庫的增刪改查
一、JSP和Servlet的簡(jiǎn)單介紹
1、Servlet和JSP簡(jiǎn)介:
Java開發(fā)Web應(yīng)用程序時(shí)用到的技術(shù)主要有兩種,即Servlet和JSP,Servlet是在服務(wù)器端執(zhí)行的Java程序,一個(gè)被稱為Servlet容器的程序(其實(shí)就是服務(wù)器) 負(fù)責(zé)執(zhí)行Java程序,而JSP(Java Server Page)則是一個(gè)頁面, 由JSP容器負(fù)責(zé)執(zhí)行.
2、Servlet和JSP的區(qū)別:
Servlet以Java程序?yàn)橹鳎?輸出HTML代碼時(shí)需要使用out.println函數(shù),也就是說Java中內(nèi)嵌HTML; 而JSP則以HTML頁面為主,需要寫Java代碼時(shí)則在頁面中直接插入Java代碼, 即HTML中內(nèi)嵌Java.
3、MVC模型
MVC模型就是將數(shù)據(jù)、邏輯處理、用戶界面分離的一種方法
1)、M(Model, 模型):用于數(shù)據(jù)處理、邏輯處理
2)、V(View,視圖):用于顯示用戶界面
3)、C(Controller,控制器):根據(jù)客戶端的請(qǐng)求控制邏輯走向和畫面
而在Java中,MVC這三個(gè)部分則分別對(duì)應(yīng)于 JavaBeans、JSP和Servlet
1)、M = JavaBeans:用于傳遞數(shù)據(jù),擁有與數(shù)據(jù)相關(guān)的邏輯處理
2)、V = JSP:從Model接收數(shù)據(jù)并生成HTML
3)、C = Servlet:接收HTTP請(qǐng)求并控制Model和View
4、jdbc連接,可參考文章:點(diǎn)擊打開鏈接
二、代碼演示,實(shí)現(xiàn)了book的添加刪除和修改功能
1、環(huán)境的配置
myeclipse+tomcat+MySQL
2、Book中bean類
package example.bean.book;
public class Book {
// 編號(hào)
private int id;
// 圖書名稱
private String name;
// 價(jià)格
private double price;
// 數(shù)量
private int bookCount;
// 作者
private String author;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public double getPrice() {
return price;
}
public void setPrice(double price) {
this.price = price;
}
public int getBookCount() {
return bookCount;
}
public void setBookCount(int bookCount) {
this.bookCount = bookCount;
}
public String getAuthor() {
return author;
}
public void setAuthor(String author) {
this.author = author;
}
}
3、Servlet類
1)、FindServlet.java
package example.servlet.book;
import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import example.bean.book.Book;
/**
* Servlet implementation class FindServlet
*/
public class FindServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
* response)
*/
protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
try {
// 加載數(shù)據(jù)庫驅(qū)動(dòng),注冊(cè)到驅(qū)動(dòng)管理器
Class.forName("com.mysql.jdbc.Driver");
// 數(shù)據(jù)庫連接字符串
String url = "jdbc:mysql://localhost:3306/db_book?useUnicode=true&characterEncoding=utf-8";
// 數(shù)據(jù)庫用戶名
String username = "root";
// 數(shù)據(jù)庫密碼
String password = "";
// 創(chuàng)建Connection連接
Connection conn = DriverManager.getConnection(url, username,
password);
// 添加圖書信息的SQL語句
String sql = "select * from tb_books";
// 獲取Statement
Statement statement = conn.createStatement();
ResultSet resultSet = statement.executeQuery(sql);
List<Book> list = new ArrayList<Book>();
while (resultSet.next()) {
Book book = new Book();
book.setId(resultSet.getInt("id"));
book.setName(resultSet.getString("name"));
book.setPrice(resultSet.getDouble("price"));
book.setBookCount(resultSet.getInt("bookCount"));
book.setAuthor(resultSet.getString("author"));
list.add(book);
}
request.setAttribute("list", list);
resultSet.close();
statement.close();
conn.close();
} catch (Exception e) {
e.printStackTrace();
}
request.getRequestDispatcher("book_list.jsp")
.forward(request, response);
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
* response)
*/
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
}
2)、UpdateServlet.java類
package example.servlet.book;
import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet implementation class UpdateServlet
*/
public class UpdateServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
* response)
*/
protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
int id = Integer.valueOf(request.getParameter("id"));
int bookCount = Integer.valueOf(request.getParameter("bookCount"));
try {
// 加載數(shù)據(jù)庫驅(qū)動(dòng),注冊(cè)到驅(qū)動(dòng)管理器
Class.forName("com.mysql.jdbc.Driver");
// 數(shù)據(jù)庫連接字符串
String url = "jdbc:mysql://localhost:3306/db_book";
// 數(shù)據(jù)庫用戶名
String username = "root";
// 數(shù)據(jù)庫密碼
String password = "";
// 創(chuàng)建Connection連接
Connection conn = DriverManager.getConnection(url, username,
password);
// 更新SQL語句
String sql = "update tb_books set bookcount=? where id=?";
// 獲取PreparedStatement
PreparedStatement ps = conn.prepareStatement(sql);
// 對(duì)SQL語句中的第一個(gè)參數(shù)賦值
ps.setInt(1, bookCount);
// 對(duì)SQL語句中的第二個(gè)參數(shù)賦值
ps.setInt(2, id);
// 執(zhí)行更新操作
ps.executeUpdate();
// 關(guān)閉PreparedStatement
ps.close();
// 關(guān)閉Connection
conn.close();
} catch (Exception e) {
e.printStackTrace();
}
// 重定向到FindServlet
response.sendRedirect("FindServlet");
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
* response)
*/
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
}
3)、DeleteServlet類
package example.servlet.book;
import java.io.IOException;
import java.sql.Connection;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import example.dao.book.BookJdbcDao;
import example.dao.book.ConnectionFactory;
/**
* Servlet implementation class DeleteServlet
*/
public class DeleteServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
* response)
*/
protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
int id = Integer.valueOf(request.getParameter("id"));
try {
// // 加載數(shù)據(jù)庫驅(qū)動(dòng),注冊(cè)到驅(qū)動(dòng)管理器
// Class.forName("com.mysql.jdbc.Driver");
// // 數(shù)據(jù)庫連接字符串
// String url = "jdbc:mysql://localhost:3306/db_book";
// // 數(shù)據(jù)庫用戶名
// String username = "root";
// // 數(shù)據(jù)庫密碼
// String password = "";
// // 創(chuàng)建Connection連接
// Connection conn = DriverManager.getConnection(url, username,
// password);
// // 刪除圖書信息的SQL語句
// String sql = "delete from tb_books where id=?";
// // 獲取PreparedStatement
// PreparedStatement ps = conn.prepareStatement(sql);
// // 對(duì)SQL語句中的第一個(gè)占位符賦值
// ps.setInt(1, id);
// // 執(zhí)行更新操作
// ps.executeUpdate();
// // 關(guān)閉PreparedStatement
// ps.close();
// // 關(guān)閉Connection
// conn.close();
BookJdbcDao bookDao=new BookJdbcDao();
Connection conn=ConnectionFactory.getInstance().getConnection();
bookDao.delete(conn,id);
} catch (Exception e) {
e.printStackTrace();
}
// 重定向到FindServlet
response.sendRedirect("FindServlet");
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
* response)
*/
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
}
4、servlet訪問url映射配置:
由于客戶端是通過URL地址訪問web服務(wù)器中的資源,所以Servlet程序若想被外界訪問,必須把servlet程序映射到一個(gè)URL地址上,這個(gè)工作在web.xml文件中使用<servlet>元素和<servlet-mapping>元素完成,<servlet>元素用于注冊(cè)Servlet,它包含有兩個(gè)主要的子元素:<servlet-name>和<servlet-class>,分別用于設(shè)置Servlet的注冊(cè)名稱和Servlet的完整類名。
一個(gè)<servlet-mapping>元素用于映射一個(gè)已注冊(cè)的Servlet的一個(gè)對(duì)外訪問路徑,它包含有兩個(gè)子元素:<servlet-name>和<url-pattern>,分別用于指定Servlet的注冊(cè)名稱和Servlet的對(duì)外訪問路徑.另外:同一個(gè)Servlet可以被映射到多個(gè)URL上,即多個(gè)<servlet-mapping>元素的<servlet-name>子元素的設(shè)置值可以是同一個(gè)Servlet的注冊(cè)名.
eg:上例中的web.xml
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5"> <display-name>JdbcConnection</display-name> <welcome-file-list> <welcome-file>index.html</welcome-file> <welcome-file>index.htm</welcome-file> <welcome-file>index.jsp</welcome-file> <welcome-file>default.html</welcome-file> <welcome-file>default.htm</welcome-file> <welcome-file>default.jsp</welcome-file> </welcome-file-list> <servlet> <description></description> <display-name>FindServlet</display-name> <servlet-name>FindServlet</servlet-name> <servlet-class>example.servlet.book.FindServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>FindServlet</servlet-name> <url-pattern>/FindServlet</url-pattern> </servlet-mapping> <servlet> <description></description> <display-name>UpdateServlet</display-name> <servlet-name>UpdateServlet</servlet-name> <servlet-class>example.servlet.book.UpdateServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>UpdateServlet</servlet-name> <url-pattern>/UpdateServlet</url-pattern> </servlet-mapping> <servlet> <description></description> <display-name>DeleteServlet</display-name> <servlet-name>DeleteServlet</servlet-name> <servlet-class>example.servlet.book.DeleteServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>DeleteServlet</servlet-name> <url-pattern>/DeleteServlet</url-pattern> </servlet-mapping> </web-app>
5、jsp頁面
1)、index.jsp web頁面主界面
<%@page import="java.sql.SQLException"%>
<%@page import="java.sql.DriverManager"%>
<%@page import="java.sql.Connection"%>
<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>添加圖書信息</title>
<script type="text/javascript">
function check(form) {
with (form) {
if (name.value == "") {
alert("圖書名稱不能為空");
return false;
}
if (price.value == "") {
alert("圖書價(jià)格不能為空");
return false;
}
if (author.value == "") {
alert("作者不能為空");
return false;
}
}
}
</script>
</head>
<body>
<form action="addbook.jsp" method="post" onsubmit="check(this)">
<table align="center" width="450">
<tr>
<td align="center" colspan="2">
<h2>添加圖書信息</h2>
<hr>
</td>
</tr>
<tr>
<td align="right">圖書名稱:</td>
<td><input type="text" name="name"></td>
</tr>
<tr>
<td align="right">價(jià) 格:</td>
<td><input type="text" name="price"></td>
</tr>
<tr>
<td align="right">數(shù) 量:</td>
<td><input type="text" name="bookCount" /></td>
</tr>
<tr>
<td align="right">作 者:</td>
<td><input type="text" name="author" /></td>
</tr>
<tr>
<td align="center" colspan="2"><input type="submit" value="添 加">
</td>
</tr>
</table>
</form>
<h2 align="center">
<a href="FindServlet">查詢圖書信息</a>
</h2>
</body>
</html>
2)、addbook.jsp 添加書籍成功或者失敗后的顯示頁面
<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<%@page import="java.sql.Connection"%>
<%@page import="java.sql.DriverManager"%>
<%@page import="java.sql.PreparedStatement"%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>添加結(jié)果</title>
</head>
<body>
<%
request.setCharacterEncoding("utf-8");
%>
<jsp:useBean id="book" class="example.bean.book.Book"></jsp:useBean>
<jsp:setProperty property="*" name="book" />
<%
try {
// 加載數(shù)據(jù)庫驅(qū)動(dòng),注冊(cè)到驅(qū)動(dòng)管理器
Class.forName("com.mysql.jdbc.Driver");
// 數(shù)據(jù)庫連接字符串
String url = "jdbc:mysql://localhost:3306/db_book?useUnicode=true&characterEncoding=utf-8";
// 數(shù)據(jù)庫用戶名
String username = "root";
// 數(shù)據(jù)庫密碼
String password = "";
// 創(chuàng)建Connection連接
Connection conn = DriverManager.getConnection(url, username,
password);
// 添加圖書信息的SQL語句
String sql = "insert into tb_books(name,price,bookCount,author) values(?,?,?,?)";
// 獲取PreparedStatement
PreparedStatement ps = conn.prepareStatement(sql);
// 對(duì)SQL語句中的第1個(gè)參數(shù)賦值
ps.setString(1, book.getName());
// 對(duì)SQL語句中的第2個(gè)參數(shù)賦值
ps.setDouble(2, book.getPrice());
// 對(duì)SQL語句中的第3個(gè)參數(shù)賦值
ps.setInt(3, book.getBookCount());
// 對(duì)SQL語句中的第4個(gè)參數(shù)賦值
ps.setString(4, book.getAuthor());
// 執(zhí)行更新操作,返回所影響的行數(shù)
int row = ps.executeUpdate();
// 判斷是否更新成功
if (row > 0) {
// 更新成輸出信息
out.print("成功添加了 " + row + "條數(shù)據(jù)!");
}
// 關(guān)閉PreparedStatement,釋放資源
ps.close();
// 關(guān)閉Connection,釋放資源
conn.close();
} catch (Exception e) {
out.print("圖書信息添加失敗!");
e.printStackTrace();
}
%>
<br>
<a href="index.jsp">返回</a>
</body>
</html>
3)、book_list.jsp 查找所有書籍信息的顯示頁面,以表格方式顯示
<!--<%@page import="sun.awt.SunHints.Value"%>-->
<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<%@page import="java.util.List"%>
<%@page import="example.bean.book.Book"%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>所有圖書信息</title>
<style type="text/css">
td {
font-size: 12px;
}
h2 {
margin: 0px
}
</style>
<script type="text/javascript">
function check(form) {
with (form) {
if (bookCount.value == "") {
alert("請(qǐng)輸入更新數(shù)量!");
return false;
}
if (isNaN(bookCount.value)) {
alert("格式錯(cuò)誤!");
return false;
}
return true;
}
}
</script>
</head>
<body>
<table align="center" width="450" border="1" height="180"
bordercolor="white" bgcolor="black" cellpadding="1" cellspacing="1">
<tr bgcolor="white">
<td align="center" colspan="7">
<h2>所有圖書信息</h2>
</td>
</tr>
<tr align="center" bgcolor="#e1ffc1">
<td><b>ID</b></td>
<td><b>圖書名稱</b></td>
<td><b>價(jià)格</b></td>
<td><b>數(shù)量</b></td>
<td><b>作者</b></td>
<td><b>修改</b></td>
<td><b>刪除</b></td>
</tr>
<%
// 獲取圖書信息集合
List<Book> list = (List<Book>) request.getAttribute("list");
// 判斷集合是否有效
if (list == null || list.size() < 1) {
out.print("沒有數(shù)據(jù)!");
} else {
// 遍歷圖書集合中的數(shù)據(jù)
for (Book book : list) {
%>
<tr align="center" bgcolor="white">
<td><%=book.getId()%></td>
<td><%=book.getName()%></td>
<td><%=book.getPrice()%></td>
<td><%=book.getBookCount()%></td>
<td><%=book.getAuthor()%></td>
<td >
<form style="align:center; background-color: gray" action="UpdateServlet" method="post"
onsubmit="return check(this);">
<input type="hidden" name="id" value="<%=book.getId()%>"> <input
type="text" name="bookCount" size="3">
<input type="submit" value="修改數(shù)量">
</form>
</td>
<td>
<a href="DeleteServlet?id=<%=book.getId()%>">刪除</a>
</td>
</tr>
<%
}
}
%>
</table>
<h2 align="center">
<a href="index.jsp">返回添加圖書信息頁面</a>
</h2>
</body>
</html>
6、jdbc簡(jiǎn)單的封裝
1)、ConnectionFactory.java工廠類
package example.dao.book;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
public class ConnectionFactory {
private String driverClassName = "com.mysql.jdbc.Driver";
private String url = "jdbc:mysql://localhost:3306/db_book?useUnicode=true&characterEncoding=utf-8";
private String userName = "root";
private String password = "";
private static ConnectionFactory connectionFactory=null;
private ConnectionFactory() {
try {
Class.forName(driverClassName);
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
}
public Connection getConnection() throws SQLException
{
return DriverManager.getConnection(url, userName, password);
}
public static ConnectionFactory getInstance()
{
if (null==connectionFactory) {
connectionFactory=new ConnectionFactory();
}
return connectionFactory;
}
}
2)、BookJdbcDao.java數(shù)據(jù)庫操作封裝類
package example.dao.book;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import example.bean.book.Book;
public class BookJdbcDao {
private PreparedStatement ptmt = null;
private ResultSet rs = null;
public BookJdbcDao() {
}
public void findAll(Connection conn) throws SQLException
{
//to do
}
public void delete(Connection conn, int id) throws SQLException
{
String sql = "delete from tb_books where id=?";
try{
ptmt = conn.prepareStatement(sql);
// 對(duì)SQL語句中的第一個(gè)占位符賦值
ptmt.setInt(1, id);
// 執(zhí)行更新操作
ptmt.executeUpdate();
}finally{
if (null!=ptmt) {
ptmt.close();
}
if (null!=conn) {
conn.close();
}
}
}
public void update(Connection conn, int id ,int bookcount) throws SQLException
{
//to do
}
}
以上就是本文的全部?jī)?nèi)容,希望對(duì)大家的學(xué)習(xí)有所幫助,也希望大家多多支持腳本之家。
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