请求和响应对象,只是提供过滤功能)
过滤器是如何配置的?如:
LoginFilter
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filter.LoginFilter LoginFilter /suc.jsp /suc2.jsp 【六】 数据库连接的步骤 1、 拿到连接 2、 生成语句对象 3、 执行语句得结果 package been;
import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException; //取数据库连接
public class DBConnection {
public static Connection getConn() { Connection conn = null; try { // 加载驱动 Class.forName("com.mysql.jdbc.Driver"); // 拿连接对象 conn = DriverManager.getConnection( "jdbc:
mysql://localhost:3306/xrex10", "root", "123456"); } catch (ClassNotFoundException e) { System.out.println("驱动异常," + e.getMessage()); } catch (SQLException e2) {
System.out.println("拿连接异常,检查连接字符串,
登陆数据库的账号、密码," + e2.getMessage()); } return conn; } }
补充1、类似实训10、实训9这样的MVC模式开发的数据库访问应用 补充2、DAO中的方法:查询 如:
package dao;
import java.sql.Connection;
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import java.
sql.PreparedStatement; import java.sql.ResultSet;
import java.sql.SQLException; import java.util.ArrayList; import java.util.List;
import bean.Book; public class BookDao { //
查询所有图书
public List
getAllBooks(){ List bookList = new ArrayList(); Connection conn = DBConnection.getConn(); String sql = "select * from bookinfo"; try{ PreparedStatement pstmt = conn.prepareStatement(sql); ResultSet rs = pstmt.executeQuery(); while(rs.next()){ Book onebook = new Book(); onebook.setId(rs.getInt("id")); onebook.setBname(rs.getString("bname")); onebook.setAuthor(rs.getString("author")); onebook.setIsbn(rs.getString("isbn")); onebook.setPrice(rs.getDouble("price")); onebook.setPublisher(rs.getString("publisher")); bookList.add(onebook); } }catch(SQLException e){ System.out.println("查询所有图书异常" + e.getMessage()); } return bookList; } }
补充3、Servlet中的代码:
取表单参数:调用HttpServletRequest的getParameter()方法,在调用参数中提供表单项的名字即可读取表单数据 调模型层的方法: 绑定数据: 转至结果页:
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