图书管理系统( ( JSP + JDBC + Servlet ) )实现-06: 查询所有书籍功能

Posted 2021-07-09 Z && Y

01: 流程分析和数据库建表阶段
02: 编写和配置过滤器（防止页面乱码）
03:项目搭建 & 工具类的实现 &依赖导入
04: 建立数据库的实体类（pojo）
05: 实现登录功能
06: 查询所有书籍功能
07:模糊查询功能
08:页面所有功能实现（附源码下载）

2.0 实现-06: 查询所有书籍功能

刚刚页面跳转过去以后，页面并没有值，现在我们在跳转过去的时候，就从后台数据库取值

2.0.1 创建 BookDao

BookDao.java

package com.tian.dao.book;

import com.tian.pojo.Book;

import java.sql.Connection;
import java.util.List;

/**
 * ClassName: BookDao
 * Description: books表的dao层
 *
 * @author Tianjiao
 * @date 2021/5/28 14:26
 */
public interface BookDao {
    /**
     * MethodName: getAllBook
     * Description: 查询所有的书籍
     */
    public List<Book> getAllBook(Connection connection) throws Exception;
}

2.0.1 创建 BookDaoImpl

BookDaoImpl.java

package com.tian.dao.book;

import com.tian.pojo.Book;
import com.tian.utils.BaseDao;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;

/**
 * ClassName: BookDaoImpl
 * Description: BookDao的实现类
 * 
 * @author Tianjiao
 * @date 2021/5/28 14:27
 */
public class BookDaoImpl implements BookDao {
    @Override
    public List<Book> getAllBook(Connection connection) throws Exception {
        PreparedStatement preparedStatement = null;
        ResultSet rs = null;
        List<Book> books = new ArrayList<>();
        Book book = null;
        if (null != connection) {
            String sql = "select * from `books`";
            Object[] params = {};
            rs = BaseDao.executeQuery(connection, preparedStatement, rs, sql, params);
            int i = 0;
            while (rs.next()) {
                book = new Book();
                book.setInventory(rs.getInt("inventory"));
                book.setBookName(rs.getString("bookName"));
                book.setBookId(rs.getString("bookId"));
                book.setAuthor(rs.getString("author"));
                books.add(book);
            }
            BaseDao.closeResource(connection, preparedStatement, rs);
        }
        return books;
    }
}

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2.0.3 创建 BookService

BookService.java

package com.tian.service.book;

import com.tian.pojo.Book;

import java.util.List;

/**
 * ClassName: BookService
 * Description: Books的service层
 *
 * @author Tianjiao
 * @date 2021/5/28 14:51
 */
public interface BookService {
    /**
     * MethodName: getAllBooks
     * Description: 获得所有的书籍
     */
    public List<Book> getAllBooks() throws Exception;
}

2.0.4 创建 BookServiceImpl

BookServiceImpl.java

package com.tian.service.book;

import com.tian.dao.book.BookDaoImpl;
import com.tian.pojo.Book;
import com.tian.utils.BaseDao;

import java.sql.Connection;
import java.util.List;

/**
 * ClassName: BookServiceImpl
 * Description: BookService的实现类
 *
 * @author Tianjiao
 * @date 2021/5/28 14:51
 */
public class BookServiceImpl implements BookService {
    @Override
    public List<Book> getAllBooks() throws Exception {
        Connection connection = BaseDao.getConnection();
        return new BookDaoImpl().getAllBook(connection);
    }
}

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2.0.5 创建 AllBookServlet

AllBookServlet.jsp

package com.tian.servlet.book;

import com.tian.pojo.Book;
import com.tian.service.book.BookServiceImpl;

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.util.List;

/**
 * ClassName: BookServlet
 * Description: 查询所有书籍的请求
 *
 * @author Tianjiao
 * @date 2021/5/29 10:30
 */
public class AllBookServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) {
        try {
            List<Book> books = new BookServiceImpl().getAllBooks();
            if (books != null) {
                req.setAttribute("books", books);
                req.getRequestDispatcher("static/jsp/index.jsp").forward(req, resp);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws EnumConstantNotPresentException {
        this.doGet(req, resp);
    }
}

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2.0.6 配置 AllBookServlet

web.xml

    <servlet>
        <servlet-name>AllBookServlet</servlet-name>
        <servlet-class>com.tian.servlet.book.AllBookServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>AllBookServlet</servlet-name>
        <url-pattern>/books</url-pattern>
    </servlet-mapping>

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2.0.7 修改 LoginServlet

修改 LoginServlet 使其在通过 /books 请求进入index.jsp页面

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2.0.8 启动服务器，测试

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