Bean/DAO/Service/Servlet简单综合应用

分层思想

dao层：在没有使用mybatis等框架的时候，完成注册、获取连接、执行sql并返回结果
service：对应一个servlet，完成调用dao的功能，返回dao层输入的结果
servlet：完成获取jsp页面信息，并反馈结果到页面中
bean：是对结果的封装（实质将已赋值的bean存在list中，然后返回list到jsp页面中）

实例

项目结构

代码块

• bean层
  Book.java

public class Book {
    //图书基本信息：书号、书名、作者、类型、价格、数量、出版日期
    private String BID;
    private String BNAME;
    private String BAUTHER;
    private String BTYPE;
    private int BPRICE;
    private int BAMOUNT;
    private Date BPUBDATE;
    //getter和setter方法省略
}

• dao
  BookDao.java

public interface BookDao {
    //增加图书
    public void addBook(Book book) throws Exception;
}

BookDaoImpl.java

public class BookDaoImpl implements BookDao {
    @Override
    public void addBook(Book book) throws Exception {
        Connection conn = null;
        PreparedStatement ps = null;
        try {
            //连接数据库
            conn = DBUtil.getConnection();
            ps = conn.prepareStatement("INSERT INTO T_BOOK VALUES (?,?,?,?,?,?,?)");
            ps.setString(1,book.getBID());
            ps.setString(2, book.getBNAME());
            ps.setString(3, book.getBAUTHER());
            ps.setString(4, book.getBTYPE());
            ps.setInt(5, book.getBPRICE());
            ps.setInt(6, book.getBAMOUNT());
            //格式化日期
            SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
            String publicDate = sdf.format(book.getBPUBDATE());
            ps.setString(7, publicDate);
            ps.executeUpdate();
            System.out.println("成功");
        }catch (Exception e){
            e.printStackTrace();
            throw new RuntimeException("添加失败！");
        }
    }
}

• service层
  BookService.java

public interface BookService {
    //增加图书
    public void addBook(Book book) throws Exception;
}

BookServiceImpl.java

public class BookServiceImpl implements BookService {
    
    BookDao bookDao = new BookDaoImpl();

    @Override
    public void addBook(Book book) throws Exception {
        bookDao.addBook(book);
    }
}

• servlet层
  addBookServlet.java

package servlet;

import bean.Book;
import service.BookService;
import service.BookServiceImpl.BookServiceImpl;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

@WebServlet(name = "AddBookServlet",urlPatterns = {"/AddBookServlet"})
public class addBookServlet extends HttpServlet {
    //确保版本的兼容性
    private static final long serialVersionUID = 1L;

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //防止中文乱码
        req.setCharacterEncoding("gb2312");
        req.setCharacterEncoding("gb2312");
        resp.setContentType("text/html;charset=gb2312");
        //把表单提交到User类中
        Book b = new Book();
        b.setBID(req.getParameter("BID"));
        b.setBNAME(req.getParameter("BNAME"));
        b.setBAUTHER(req.getParameter("BAUTHER"));
        b.setBTYPE(req.getParameter("BTYPE"));
        b.setBPRICE(Integer.parseInt(req.getParameter("BPRICE")));
        b.setBAMOUNT(Integer.parseInt(req.getParameter("BAMOUNT")));
        String publicDate = req.getParameter("BPUBDATE");
        
            try {
                SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
                Date date = sdf.parse(publicDate);
                b.setBPUBDATE(date);
                resp.getWriter().write("<p>图书添加成功！</p><br>");
        }catch (ParseException e){
                e.printStackTrace();
                System.out.println("添加失败！");
            }
            
            //调用业务逻辑层
        BookService bookService = new BookServiceImpl();
            try {
                bookService.addBook(b);
            }catch (Exception e){
                e.printStackTrace();
            }           
    }
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doPost(req, resp);
    }
}

• JSP查询页面

<%@ page contentType="text/html;charset=gb2312" language="java" import="java.sql.*" %>
<html>
<head><title>图书增加</title></head>
<body>
<h1>图书增加</h1>
<form method="post" action="AddBookServlet">

    书号:<input name="BID" type="text" id="BID" /><br>
    书名:<input name="BNAME" type="text" id="BNAME" /><br>
    作者:<input name="BAUTHER" type="text" id="BAUTHER" /><br>
    类型:<input name="BTYPE" type="text" id="BTYPE" /><br>
    价格:<input name="BPRICE" type="text" id="BPRICE" /><br>
    数量:<input name="BAMOUNT" type="text" id="BAMOUNT" /><br>
    出版日期:<input name="BPUBDATE" type="text" id="BPUBDATE" /><br>

    <input name="submit" type="submit" value="确定" />
    <input name="reset" type="reset" value="重置" />
</form>
</body>
</html>