一、JSP和Servlet的简单介绍
1、Servlet和JSP简介:
Java开发Web应用程序时用到的技术主要有两种,即Servlet和JSP,Servlet是在服务器端执行的Java程序,一个被称为Servlet容器的程序(其实就是服务器) 负责执行Java程序,而JSP(Java Server Page)则是一个页面, 由JSP容器负责执行.
2、Servlet和JSP的区别:
Servlet以Java程序为主, 输出HTML代码时需要使用out.println函数,也就是说Java中内嵌HTML; 而JSP则以HTML页面为主,需要写Java代码时则在页面中直接插入Java代码, 即HTML中内嵌Java.
3、MVC模型
MVC模型就是将数据、逻辑处理、用户界面分离的一种方法
1)、M(Model, 模型):用于数据处理、逻辑处理
2)、V(View,视图):用于显示用户界面
3)、C(Controller,控制器):根据客户端的请求控制逻辑走向和画面
而在Java中,MVC这三个部分则分别对应于 JavaBeans、JSP和Servlet
1)、M = JavaBeans:用于传递数据,拥有与数据相关的逻辑处理
2)、V = JSP:从Model接收数据并生成HTML
3)、C = Servlet:接收HTTP请求并控制Model和View
4、jdbc连接,可参考文章:点击打开链接
二、代码演示,实现了book的添加删除和修改功能
1、环境的配置
myeclipse+tomcat+MySQL
2、Book中bean类
package example.bean.book;
public class Book {
// 编号
private int id;
// 图书名称
private String name;
// 价格
private double price;
// 数量
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;
}
}
</div>
3、Servlet类
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 {
// 加载数据库驱动,注册到驱动管理器
Class.forName("com.mysql.jdbc.Driver");
// 数据库连接字符串
String url = "jdbc:mysql://localhost:3306/db_book?useUnicode=true&characterEncoding=utf-8";
// 数据库用户名
String username = "root";
// 数据库密码
String password = "";
// 创建Connection连接
Connection conn = DriverManager.getConnection(url, username,
password);
// 添加图书信息的SQL语句
String sql = "select * from tb_books";
// 获取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);
}
}
</div>
2)、UpdateServlet.java类
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 {
// 加载数据库驱动,注册到驱动管理器
Class.forName("com.mysql.jdbc.Driver");
// 数据库连接字符串
String url = "jdbc:mysql://localhost:3306/db_book";
// 数据库用户名
String username = "root";
// 数据库密码
String password = "";
// 创建Connection连接
Connection conn = DriverManager.getConnection(url, username,
password);
// 更新SQL语句
String sql = "update tb_books set bookcount=? where id=?";
// 获取PreparedStatement
PreparedStatement ps = conn.prepareStatement(sql);
// 对SQL语句中的第一个参数赋值
ps.setInt(1, bookCount);
// 对SQL语句中的第二个参数赋值
ps.setInt(2, id);
// 执行更新操作
ps.executeUpdate();
// 关闭PreparedStatement
ps.close();
// 关闭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);
}
}
</div>
3)、DeleteServlet类
package example.servlet.book; import java.io.IOException; import java.sql.Connection; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet

