图书系统优化分页与搜索跳转

2020-10-23 10:42:00 浏览数 (1)

实现效果图

1.优化分页

使用jstl，所以需要在web–>web-inf下导包，再导入引用

代码语言：javascript复制
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ taglib prefix="fmt" uri="http://java.sun.com/jsp/jstl/fmt" %>
代码语言：javascript复制
<%--页码--%>
        <c:forEach var="num" begin="${pageBean.startPage}" end="${pageBean.endPage}">
            <c:if test="${pageBean.pageNum==num}">
                <a class="class1" href="${pageContext.request.contextPath}/booklist?pageNum=${num}&pageSize=${pageBean.pageSize}&search=${search}&author=${author}">${num}</a>
            </c:if>
            <c:if test="${pageBean.pageNum!=num}">
                <a href="${pageContext.request.contextPath}/booklist?pageNum=${num}&pageSize=${pageBean.pageSize}&search=${search}&author=${author}">${num} </a>
            </c:if>
        </c:forEach>

2.搜索跳转

代码语言：javascript复制
<style type="text/css">
    a{
        text-decoration: none;
        color: cornflowerblue;
    }
    a:hover{
        text-decoration: underline;
    }
    .class1 {
        background-color: brown;
        color: white;
    }
</style>

在每个页面跳转的a标签中拼接上自己的搜索条件：

代码语言：javascript复制
&search=${search}&author=${author}

<%–添加搜索框，点击搜索跳转至booklist处理数据–%>

代码语言：javascript复制
<form action="${pageContext.request.contextPath}/booklist" method="post">
        <input type="text" name="search" value="${search}">
        <input type="text" name="author" value="${author}">
        <input type="submit" value="搜索">
    </form>
代码语言：javascript复制
<div>
        <a href="${pageContext.request.contextPath}/booklist?pageNum=1&pageSize=${pageBean.pageSize}">首页</a>
        <a href="${pageContext.request.contextPath}/booklist?pageNum=${pageBean.pageNum-1}&pageSize=${pageBean.pageSize}">上一页</a>

        <%--页码--%>
        <c:forEach var="num" begin="${pageBean.startPage}" end="${pageBean.endPage}">
            <c:if test="${pageBean.pageNum==num}">
                <a class="class1" href="${pageContext.request.contextPath}/booklist?pageNum=${num}&pageSize=${pageBean.pageSize}&search=${search}&author=${author}">${num}</a>
            </c:if>
            <c:if test="${pageBean.pageNum!=num}">
                <a href="${pageContext.request.contextPath}/booklist?pageNum=${num}&pageSize=${pageBean.pageSize}&search=${search}&author=${author}">${num} </a>
            </c:if>
        </c:forEach>

        <c:if test="${pageBean.pageNum>=pageBean.pageCount}">
            <a href="${pageContext.request.contextPath}/booklist?pageNum=${pageBean.pageCount}&pageSize=${pageBean.pageSize}&search=${search}&author=${author}">下一页</a>
        </c:if>
        <c:if test="${pageBean.pageNum<pageBean.pageCount}">
            <a href="${pageContext.request.contextPath}/booklist?pageNum=${pageBean.pageNum 1}&pageSize=${pageBean.pageSize}&search=${search}&author=${author}">下一页</a>
        </c:if>
        <a href="${pageContext.request.contextPath}/booklist?pageNum=${pageBean.pageCount}&pageSize=${pageBean.pageSize}&search=${search}&author=${author}">尾页</a>
        共【${pageBean.pageCount}/${pageBean.pageNum}】页 <input id="page" type="number" name="page" min="1" max="${pageBean.pageCount}"><input type="button" value="跳转" onclick="judgePage()">
    </div>
    <script type="text/javascript">
        function judgePage() {
            var n=document.getElementById("page").value;
            window.location="${pageContext.request.contextPath}/booklist?pageNum=" n "&pageSize=${pageBean.pageSize}&search=${search}&author=${author}";
        }
    </script>

在servlet中获取jsp中输入的条件（书名称，作者），并且将它们放入request域中（servlet跳转至booklist时，在booklist中获取request域中的数据来拼接到a标签后面进行查询满足条件的书籍数据） //获取页码和页大小

代码语言：javascript复制
//获取页码和页大小
        String pageNum = request.getParameter("pageNum");
        String pageSize = request.getParameter("pageSize");
        String search = request.getParameter("search");
        String author = request.getParameter("author");

        String condition="";
        if(!StringUtils.isEmpty(search)){
            condition =" where title like '%" search "%'";
        }
        if(!StringUtils.isEmpty(author)){
            if(condition.equals("")){
                condition  = " where author like '%" author "%'";
            }else{
                condition  = " and author like '%" author "%'";
            }
        }
代码语言：javascript复制
PageBean<Book> pageBean=bookService.queryByPage(page_num, page_size,condition);
            request.setAttribute("pageBean", pageBean);
            request.setAttribute("search", search);
            request.setAttribute("author", author);
            request.getRequestDispatcher("/booklist.jsp").forward(request, response);

修改dao层与service层中的查询方法以及它们的参数，将condition添加进去，如：

代码语言：javascript复制
private QueryRunner qr=new QueryRunner();
    @Override
    public List<Book> queryByPage(int pageNum, int pageSize, String condition) {
        Connection conn= DruidUtils.getConnection();
        String sql=null;
        if(condition.equals("")) {
            sql = "select id,title,author,publicDate,publisher,isbn,price,picture,cid from book order by id limit ?,?";
        }else{
            sql= "select id,title,author,publicDate,publisher,isbn,price,picture,cid from book " condition " order by id limit ?,?";
        }

        try {
            Object[] params={(pageNum-1)*pageSize,pageSize};
            return qr.query(conn, sql, new BeanListHandler<Book>(Book.class),params);
        } catch (SQLException e) {
            e.printStackTrace();
            throw new RuntimeException("分页查询失败",e);
        }finally {
            DruidUtils.closeAll(null,null,conn);
        }

    }

3完整代码

booklist.jsp页面

代码语言：javascript复制
<%--
  Created by IntelliJ IDEA.
  User: wgy
  Date: 2020/9/2
  Time: 11:10
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ taglib prefix="fmt" uri="http://java.sun.com/jsp/jstl/fmt" %>
<html>
<head>
    <title>书籍列表</title>
</head>
<style type="text/css">
    a{
        text-decoration: none;
        color: cornflowerblue;
    }
    a:hover{
        text-decoration: underline;
    }
    .class1 {
        background-color: brown;
        color: white;
    }
</style>
<body>
    <h2>书籍列表</h2>
<%--添加搜索框跳转至booklist处理数据--%>
    <form action="${pageContext.request.contextPath}/booklist" method="post">
        <input type="text" name="search" value="${search}">
        <input type="text" name="author" value="${author}">
        <input type="submit" value="搜索">
    </form>
    <table border="1" width="100%">
        <tr>
            <th>编号</th>
            <th>书名</th>
            <th>作者</th>
            <th>出版日期</th>
            <th>出版社</th>
            <th>isbn</th>
            <th>价格</th>
            <th>图片</th>
            <th>类别</th>
            <th>操作</th>
        </tr>
        <c:forEach var="book" items="${pageBean.data}">
            <tr>
                <td>${book.id}</td>
                <td>${book.title}</td>
                <td>${book.author}</td>
                <td><fmt:formatDate value="${book.publicDate}" pattern="yyyy-MM-dd"></fmt:formatDate></td>
                <td>${book.publisher}</td>
                <td>${book.isbn}</td>
                <td>${book.price}</td>
                <td><img src="${pageContext.request.contextPath}/picture?pic=${book.picture}" width="50" height="50"></td>
                <td>${book.cid}</td>
                <td><a href="${pageContext.request.contextPath}/editbook?bid=${book.id}">修改</a><a>删除</a></td>
            </tr>
        </c:forEach>
    </table>
    <div>
        <a href="${pageContext.request.contextPath}/booklist?pageNum=1&pageSize=${pageBean.pageSize}">首页</a>
        <a href="${pageContext.request.contextPath}/booklist?pageNum=${pageBean.pageNum-1}&pageSize=${pageBean.pageSize}">上一页</a>

        <%--页码--%>
        <c:forEach var="num" begin="${pageBean.startPage}" end="${pageBean.endPage}">
            <c:if test="${pageBean.pageNum==num}">
                <a class="class1" href="${pageContext.request.contextPath}/booklist?pageNum=${num}&pageSize=${pageBean.pageSize}&search=${search}&author=${author}">${num}</a>
            </c:if>
            <c:if test="${pageBean.pageNum!=num}">
                <a href="${pageContext.request.contextPath}/booklist?pageNum=${num}&pageSize=${pageBean.pageSize}&search=${search}&author=${author}">${num} </a>
            </c:if>
        </c:forEach>

        <c:if test="${pageBean.pageNum>=pageBean.pageCount}">
            <a href="${pageContext.request.contextPath}/booklist?pageNum=${pageBean.pageCount}&pageSize=${pageBean.pageSize}&search=${search}&author=${author}">下一页</a>
        </c:if>
        <c:if test="${pageBean.pageNum<pageBean.pageCount}">
            <a href="${pageContext.request.contextPath}/booklist?pageNum=${pageBean.pageNum 1}&pageSize=${pageBean.pageSize}&search=${search}&author=${author}">下一页</a>
        </c:if>
        <a href="${pageContext.request.contextPath}/booklist?pageNum=${pageBean.pageCount}&pageSize=${pageBean.pageSize}&search=${search}&author=${author}">尾页</a>
        共【${pageBean.pageCount}/${pageBean.pageNum}】页 <input id="page" type="number" name="page" min="1" max="${pageBean.pageCount}"><input type="button" value="跳转" onclick="judgePage()">
    </div>
    <script type="text/javascript">
        function judgePage() {
            var n=document.getElementById("page").value;
            window.location="${pageContext.request.contextPath}/booklist?pageNum=" n "&pageSize=${pageBean.pageSize}&search=${search}&author=${author}";
        }
    </script>
</body>
</html>

servlet层：BookListServlet

代码语言：javascript复制
package com.qf.web.servlet;

import com.qf.domain.Book;
import com.qf.service.BookService;
import com.qf.service.impl.BookServiceImpl;
import com.qf.utils.PageBean;
import com.qf.utils.StringUtils;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/*
 * wgy
 * 2020/9/2
 * 17:43
 */
@WebServlet(name = "BookListServlet",value = "/booklist")
public class BookListServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        request.setCharacterEncoding("utf-8");
        //获取页码和页大小
        String pageNum = request.getParameter("pageNum");
        String pageSize = request.getParameter("pageSize");
        String search = request.getParameter("search");
        String author = request.getParameter("author");

        String condition="";
        if(!StringUtils.isEmpty(search)){
            condition =" where title like '%" search "%'";
        }
        if(!StringUtils.isEmpty(author)){
            if(condition.equals("")){
                condition  = " where author like '%" author "%'";
            }else{
                condition  = " and author like '%" author "%'";
            }
        }

        int page_num=1;
        int page_size=5;
        if(!StringUtils.isEmpty(pageNum)){
            page_num=Integer.parseInt(pageNum);
            if(page_num<=0){
                page_num=1;
            }
        }
        if(!StringUtils.isEmpty(pageSize)){
            page_size=Integer.parseInt(pageSize);
        }
        //查询
        BookService bookService=new BookServiceImpl();
        try {
            PageBean<Book> pageBean=bookService.queryByPage(page_num, page_size,condition);
            request.setAttribute("pageBean", pageBean);
            request.setAttribute("search", search);
            request.setAttribute("author", author);
            request.getRequestDispatcher("/booklist.jsp").forward(request, response);
        } catch (Exception e) {
            e.printStackTrace();
            request.setAttribute("msg", "查询失败:" e.getMessage());
            request.getRequestDispatcher("/message.jsp").forward(request, response);
        }

    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doPost(request, response);
    }
}

utils层DruidUtils

代码语言：javascript复制
package com.qf.utils;

import com.alibaba.druid.pool.DruidDataSource;
import com.alibaba.druid.pool.DruidDataSourceFactory;

import javax.sql.DataSource;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;

/*
 * wgy
 * 2020/8/31
 * 9:35
 */
public class DruidUtils {

    private static DruidDataSource dataSource=null;
    private static ThreadLocal<Connection> threadLocal=new ThreadLocal<>();
    static {
        //初始化dataSource
        try {
            Properties properties=new Properties();
            InputStream is = DruidUtils.class.getClassLoader().getResourceAsStream("druid.properties");
            properties.load(is);
            is.close();
            dataSource= (DruidDataSource) DruidDataSourceFactory.createDataSource(properties);
        } catch (Exception e) {
            e.printStackTrace();
            System.out.println("初始化连接池shibai");
        }
    }

    public static DataSource getDateSource(){
        return dataSource;
    }

    public static Connection getConnection(){
        try {
            Connection conn = threadLocal.get();
            if(conn==null){
                conn=dataSource.getConnection();
                threadLocal.set(conn);
            }
            return conn;
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return null;
    }

    public static void closeAll(ResultSet rs, Statement stat,Connection conn){
        try {
            if(rs!=null){
                rs.close();
            }
            if(stat!=null){
                stat.close();
            }
            if(conn!=null){
                if(conn.getAutoCommit()) {
                    threadLocal.remove();
                    conn.close();
                }
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    //事务有关的方法
    public static void beginTransaction() throws SQLException{
        Connection conn=getConnection();
        if(conn!=null){
            conn.setAutoCommit(false);
        }
    }
    public static void commit() throws SQLException{
        Connection conn=getConnection();
        if(conn!=null){
            conn.commit();
        }
    }

    public static void rollback() throws SQLException{
        Connection conn=getConnection();
        if(conn!=null){
            conn.rollback();
        }
    }

    public static void close() throws SQLException{
        Connection conn=getConnection();
        if(conn!=null){
            threadLocal.remove();
            conn.close();
        }
    }
}

utils层PageBean（自己创建的，用来存储分页数据的实体类）

代码语言：javascript复制
package com.qf.utils;

import java.util.List;

/*
 * wgy
 * 2020/9/2
 * 17:39
 */
public class PageBean<T> {
    //当前页
    private int pageNum;
    //总页数
    private int pageCount;
    //页大小
    private int pageSize;
    //总数据个数
    private long totalSize;
    //分页数据
    private List<T> data;

    private int startPage;
    private int endPage;

    public int getStartPage() {
        return startPage;
    }

    public void setStartPage(int startPage) {
        this.startPage = startPage;
    }

    public int getEndPage() {
        return endPage;
    }

    public void setEndPage(int endPage) {
        this.endPage = endPage;
    }

    public PageBean(int pageNum, int pageSize, long totalSize, List<T> data) {
        this.pageNum = pageNum;
        this.pageSize = pageSize;
        this.totalSize = totalSize;
        this.data = data;

        //计算pageCount
        pageCount= (int) (totalSize%pageSize==0?totalSize/pageSize:totalSize/pageSize 1);//1

        //页码，第一种情况
        startPage=pageNum-4;
        endPage=pageNum 5;
        //第二种情况
        if(pageNum<5){
            startPage=1;
            endPage=10;
        }
        //第三种情况，页码小于5页
        if(pageNum>pageCount-5){
            startPage=pageCount-9;
            endPage=pageCount;
        }
        //第四种情况,总页数小于10
        if(pageCount<10){
            startPage=1;
            endPage=pageCount;
        }
    }

    public PageBean() {
    }

    public int getPageNum() {
        return pageNum;
    }

    public void setPageNum(int pageNum) {
        this.pageNum = pageNum;
    }

    public int getPageCount() {
        return pageCount;
    }

    public void setPageCount(int pageCount) {
        this.pageCount = pageCount;
    }

    public int getPageSize() {
        return pageSize;
    }

    public void setPageSize(int pageSize) {
        this.pageSize = pageSize;
    }

    public long getTotalSize() {
        return totalSize;
    }

    public void setTotalSize(long totalSize) {
        this.totalSize = totalSize;
    }

    public List<T> getData() {
        return data;
    }

    public void setData(List<T> data) {
        this.data = data;
    }

    @Override
    public String toString() {
        return "PageBean{"  
                "pageNum="   pageNum  
                ", pageCount="   pageCount  
                ", pageSize="   pageSize  
                ", totalSize="   totalSize  
                ", data="   data  
                '}';
    }
}

utils层StringUtils

代码语言：javascript复制
public class StringUtils {
    public static boolean isEmpty(String str){
        return str==null||str.trim().equals("");
    }
}

dao层BookDaoImpl

代码语言：javascript复制
public class BookDaoImpl implements BookDao {
    private QueryRunner qr=new QueryRunner();
    @Override
    public List<Book> queryByPage(int pageNum, int pageSize, String condition) {
        Connection conn= DruidUtils.getConnection();
        String sql=null;
        if(condition.equals("")) {
            sql = "select id,title,author,publicDate,publisher,isbn,price,picture,cid from book order by id limit ?,?";
        }else{
            sql= "select id,title,author,publicDate,publisher,isbn,price,picture,cid from book " condition " order by id limit ?,?";
        }

        try {
            Object[] params={(pageNum-1)*pageSize,pageSize};
            return qr.query(conn, sql, new BeanListHandler<Book>(Book.class),params);
        } catch (SQLException e) {
            e.printStackTrace();
            throw new RuntimeException("分页查询失败",e);
        }finally {
            DruidUtils.closeAll(null,null,conn);
        }

    }

    @Override
    public long getCount(String condition) {
        Connection conn= DruidUtils.getConnection();
        String sql="select count(*) from book;";
        try {
            return qr.query(conn, sql, new ScalarHandler<>());
        } catch (SQLException e) {
            e.printStackTrace();
            throw new RuntimeException("获取数据个数",e);
        }finally {
            DruidUtils.closeAll(null,null,conn);
        }
    }

    @Override
    public void add(Book book) {
        Connection conn= DruidUtils.getConnection();
        String sql="insert into book(title,author,publicDate,publisher,isbn,price,picture,cid) values(?,?,?,?,?,?,?,?)";
        Object[] params={book.getTitle(),book.getAuthor(),book.getPublicDate(),book.getPublisher(),book.getIsbn(),book.getPrice(),book.getPicture(),book.getCid()};

        try {
            qr.update(conn, sql, params);
        } catch (SQLException e) {
            e.printStackTrace();
            throw new RuntimeException("添加书籍失败",e);
        }finally {
            DruidUtils.closeAll(null,null,conn);
        }
    }
}

dao层BookDao

代码语言：javascript复制
public interface BookDao {

    //分页查询方法
    List<Book> queryByPage(int pageNum, int pageSize, String condition);

    //获取数据个数

    long getCount(String condition);

    void add(Book book);

}

service层BookService

代码语言：javascript复制
public interface BookService {

    void save(Book book);

    PageBean<Book> queryByPage(int page_num, int page_size, String condition);
}

service层BookServiceImpl

代码语言：javascript复制
public class BookServiceImpl implements BookService {

    private BookDao bookDao=new BookDaoImpl();
    @Override
    public PageBean<Book> queryByPage(int pageNum, int pageSize,String condition) {
        //查询总的数据个数
        long count = bookDao.getCount(condition);
        List<Book> books = bookDao.queryByPage(pageNum, pageSize,condition);
        PageBean<Book> pageBean=new PageBean<>(pageNum,pageSize,count,books);
        return pageBean;
    }

    @Override
    public void save(Book book) {
        bookDao.add(book);
    }
}
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