通用分页jsp页面显示

2022-12-07 20:51:38

注：本章内容都是在上一篇文章通用分页后台显示：https://www.cnblogs.com/ly-0919/p/11058942.html 的基础上进行改进，所以有许多的类都在上一篇，

带来不便请谅解！！！

通用分页的核心

.将上一次查询请求再发一次，只不过改变了页码。

本章重点：

1、改造上次PageBean里的内容；

2、页面展示
3、创建控制层 servlet
4、自定义分页标签

5、助手类信息

1、补全后的PageBean：

package com.yuan.util;

import java.util.HashMap;

import java.util.Map;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

/**

 * 分页工具类

 *

 */

public class PageBean {

    private int page = ;// 页码

    private int rows = ;// 页大小

    private int total = ;// 总记录数

    private boolean pagination = true;// 是否分页

    private Map<String, String[]>  paMap = new HashMap<>();

    private String url;

    public void setRequest(HttpServletRequest req) {

        Map<String, String[]> parameterMap = req.getParameterMap();

        StringBuffer url = req.getRequestURL();

        //保存上一次请求所携带的参数

        this.setPaMap(req.getParameterMap());

        this.setUrl(req.getRequestURL().toString());

        //在jsp页面来控制是否分页

//        this.setPagination(req.getParameter("pagination"));

        //在jsp页面控制一页展示多少条信息

//        this.setRows(req.getParameter("rows"));

        this.setPage(req.getParameter("page"));

    }

    //setPage重载

    private void setPage(String page) {

        this.page = StringUtils.isNotBlank(page) ? Integer.valueOf(page):this.page;

    }

    //setPagination重载

    public void setPagination(String pagination) {

        this.pagination = StringUtils.isNotBlank(pagination) ? !"false".equals(pagination):this.pagination;

    }

    //setRows重载

    public void setRows(String rows) {

        this.rows = StringUtils.isNotBlank(rows)?Integer.valueOf(rows):this.rows;

    }

    public Map<String, String[]> getPaMap() {

        return paMap;

    }

    public void setPaMap(Map<String, String[]> paMap) {

        this.paMap = paMap;

    }

    public String getUrl() {

        return url;

    }

    public void setUrl(String url) {

        this.url = url;

    }

    public PageBean() {

        super();

    }

    public int getPage() {

        return page;

    }

    public void setPage(int page) {

        this.page = page;

    }

    public int getRows() {

        return rows;

    }

    public void setRows(int rows) {

        this.rows = rows;

    }

    public int getTotal() {

        return total;

    }

    public void setTotal(int total) {

        this.total = total;

    }

    public void setTotal(String total) {

        this.total = Integer.parseInt(total);

    }

    public boolean isPagination() {

        return pagination;

    }

    public void setPagination(boolean pagination) {

        this.pagination = pagination;

    }

    /**

     * 获得起始记录的下标

     *

     * @return

     */

    public int getStartIndex() {

        return (this.page - ) * this.rows;

    }

    @Override

    public String toString() {

        return "PageBean [page=" + page + ", rows=" + rows + ", total=" + total + ", pagination=" + pagination + "]";

    }

    /**

     * 获取最大页码数

     * @return

     */

    public int getMaxPage() {

        return this.total % this.rows ==  ? this.total / this.rows : this.total / this.rows+;

    }

    /**

     * 下一页

     * @return

     */

    public int getNexPage() {

        return this.page < this.getMaxPage() ? this.page+ : this.page;

    }

    /**

     * 上一页

     * @return

     */

    public int getPreviousPage() {

        return this.page >  ? this.page- : this.page;

    }

}

2、jsp页面展示，分页代码插入到了控制层的Servlet里面

<%@ page language="java" contentType="text/html; charset=UTF-8"

    pageEncoding="UTF-8"%>

    <%@ page isELIgnored="false"%>  <!-- 中途遇到EL表达式（${}）失效，插入此代码解决 -->

    <%@taglib prefix="z" uri="/yuan" %>  <!-- 导入自定义标签库使用自定义的分页标签 -->

    <%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<html>

<head>

<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">

<title>Insert title here</title>

</head>

<body>

<c:if test="${empty bookList }">

<jsp:forward page="bookServlet.action"></jsp:forward>

</c:if>

<h2>小说目录</h2>

    <br>

    <form action="${pageContext.request.contextPath}/bookServlet.action"

        method="post">

        书名：<input type="text" name="bname"> <input type="submit"

            value="确定">

            <input type="hidden" name="pagination" value="false">

            <input type="hidden" name="rows" value="">

    </form>

    <table border="" width="100%">

        <tr>

            <td>编号</td>

            <td>名称</td>

            <td>价格</td>

        </tr>

        <c:forEach items="${bookList }" var="s">

            <tr>

                <td>${s.bid }</td>

                <td>${s.bname }</td>

                <td>${s.price}</td>

            </tr>

            </c:forEach>

    </table>

    <z:Page pageBean="${pageBean }"></z:Page>

</body>

</html>

3、创建控制层Servlet

package com.web;

import java.io.IOException;

import java.sql.SQLException;

import java.util.List;

import java.util.Map;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import com.yuan.dao.BookDao;

import com.yuan.entity.Book;

import com.yuan.util.PageBean;

public class BookServlet extends HttpServlet {

    /**

     *

     */

    private static final long serialVersionUID = 1L;

    private BookDao bookDao = new BookDao();

    @Override

    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        doPost(req, resp);

    }

    @Override

    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        String bname = req.getParameter("bname");

        Book book = new Book();

        book.setBname(bname);

//

        PageBean bean = new PageBean();

        try {

            bean.setRequest(req);

            List<Book> list = this.bookDao.list(book,bean);

            req.setAttribute("bookList", list);

            req.setAttribute("pageBean", bean);

            req.getRequestDispatcher("/BookList.jsp").forward(req, resp);

        } catch (InstantiationException | IllegalAccessException | SQLException e) {

            // TODO Auto-generated catch block

            e.printStackTrace();

        }

    }

}

附：web.xml文件配置

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.2//EN" "http://java.sun.com/j2ee/dtds/web-app_2_2.dtd">

<web-app id="WebApp_ID">

    <display-name>Test_pagebean</display-name>

    <servlet>

      <servlet-name>bookServlet</servlet-name>

      <servlet-class>com.web.BookServlet</servlet-class>

    </servlet>

    <servlet-mapping>

      <servlet-name>bookServlet</servlet-name>

      <url-pattern>/bookServlet.action</url-pattern>

    </servlet-mapping>

</web-app>

4、自定义分页标签

package com.tag;

import java.io.IOException;

import java.util.Map;

import java.util.Map.Entry;

import java.util.Set;

import javax.servlet.jsp.JspException;

import javax.servlet.jsp.JspWriter;

import javax.servlet.jsp.tagext.BodyTagSupport;

import com.yuan.util.PageBean;

public class PageTag extends BodyTagSupport {

    /**

     *

     */

    private static final long serialVersionUID = 1L;

    private PageBean pageBean;

    public PageBean getPageBean() {

        return pageBean;

    }

    public void setPageBean(PageBean pageBean) {

        this.pageBean = pageBean;

    }

    @Override

    public int doStartTag() throws JspException {

        JspWriter out = pageContext.getOut();

        try {

            out.print(toHTML());

        } catch (IOException e) {

            // TODO Auto-generated catch block

            e.printStackTrace();

        }

        return super.doStartTag();

    }

    private String toHTML() {

        StringBuilder sb= new StringBuilder();

        //拼接下一次发送请求所要提交的隐藏的form表单

        sb.append("<form id='pageBeanForm' action='"+pageBean.getUrl()+"' method='post'>");

        sb.append("<input type='hidden' name='page'>");

        Map<String, String[]> paMap = pageBean.getPaMap();

        if(paMap != null && paMap.size()>0) {

            Set<Entry<String, String[]>> entrySet = paMap.entrySet();

            for (Entry<String, String[]> entry : entrySet) {

                //上一次请求可能携带页码name=page的参数，但是改参数在前面已经单独赋值，

                //因为上一次请求是第一页的数据，下一次可能是第二页，一位这前后请求page对应的值是不一样的，需要单独赋值

                if(!"page".equals(entry.getKey())) {

                for(String val:entry.getValue()) {

                    sb.append("<input type='hidden' name='"+entry.getKey()+"' value='"+val+"'>");

                }

              }

            }

        }

        sb.append("</form>");

        //拼接分页条

        sb.append("<div style='text-align: right; font-size: 12px;'>");

        sb.append("每页"+pageBean.getRows()+"条，共"+pageBean.getTotal()+"条，第"+pageBean.getPage()+"页，共"+pageBean.getMaxPage()+"页&nbsp;&nbsp;<a  ");

        sb.append(" href='javascript:gotoPage(1)'>首页</a>&nbsp;&nbsp;<a");

        sb.append(" href='javascript:gotoPage("+pageBean.getPreviousPage()+")'>上一页</a>&nbsp;&nbsp;<a");

        sb.append(" href='javascript:gotoPage("+pageBean.getNexPage()+")'>下一页</a>&nbsp;&nbsp;<a");

        sb.append(" href='javascript:gotoPage("+pageBean.getMaxPage()+")'>尾页</a>&nbsp;&nbsp;<input type='text'");

        sb.append(" id='skipPage'");

        sb.append(" style='text-align: center; font-size: 12px; width: 50px;'>&nbsp;&nbsp;<a");

        sb.append(" href='javascript:skipPage()'>Go</a>");

        sb.append("</div>");

        //拼接分页所需要的js代码

        sb.append("<script type='text/javascript'>");

        sb.append(" function gotoPage(page) {");

        sb.append(" document.getElementById('pageBeanForm').page.value = page;");

        sb.append(" document.getElementById('pageBeanForm').submit();");

        sb.append(" }");

        sb.append(" function skipPage() {");

        sb.append(" var page = document.getElementById('skipPage').value;");

        sb.append(" if(!page || isNaN(page) || parseInt(page)<1 || parseInt(page)>"+pageBean.getMaxPage()+"){");

        sb.append(" alert('请输入1~N的数字');");

        sb.append(" return;");

        sb.append(" }");

        sb.append(" gotoPage(page);");

        sb.append(" }");

        sb.append(" </script>");

        return sb.toString();

    }

}

.注意在append拼接时需要注意空格

将自定义标签的类配到tld文件中

<!DOCTYPE taglib

  PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.2//EN"

   "http://java.sun.com/dtd/web-jsptaglibrary_1_2.dtd">

<!-- 标签库描述符 -->

<taglib xmlns="http://java.sun.com/JSP/TagLibraryDescriptor">

    <!-- 代表标签库的版本号 -->

    <tlib-version>1.0</tlib-version>

    <!-- 代表jsp的版本 -->

    <jsp-version>1.2</jsp-version>

    <!-- 你的标签库的简称 -->

    <short-name>test</short-name>

    <!-- 你标签库的引用uri -->

    <uri>/zking</uri>

    <!-- 1自定义分页标签 -->

    <tag>

      <name>Page</name>  //标签库中的标签名

      <tag-class>com.tag.PageTag</tag-class>//标签的助手类全路径名

      <body-content>JSP</body-content>

      <attribute>

         <name>pageBean</name>//标签属性名   在配置的时候必须与助手类的属性一致

         <required>true</required>//该属性是否必填

         <rtexprvalue>true</rtexprvalue>//是否支持表达式（EL）

      </attribute>

    </tag>

    </taglib>

5、助手类信息

StringUtils :

package com.yuan.util;

public class StringUtils {

    // 私有的构造方法，保护此类不能在外部实例化

    private StringUtils() {

    }

    /**

     * 如果字符串等于null或去空格后等于""，则返回true，否则返回false

     *

     * @param s

     * @return

     */

    public static boolean isBlank(String s) {

        boolean b = false;

        if (null == s || s.trim().equals("")) {

            b = true;

        }

        return b;

    }

    /**

     * 如果字符串不等于null或去空格后不等于""，则返回true，否则返回false

     *

     * @param s

     * @return

     */

    public static boolean isNotBlank(String s) {

        return !isBlank(s);

    }

}

EncodingFiter :

package com.yuan.util;

import java.io.IOException;

import java.util.Iterator;

import java.util.Map;

import java.util.Set;

import javax.servlet.Filter;

import javax.servlet.FilterChain;

import javax.servlet.FilterConfig;

import javax.servlet.ServletException;

import javax.servlet.ServletRequest;

import javax.servlet.ServletResponse;

import javax.servlet.annotation.WebFilter;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

/**

 * 中文乱码处理

 *

 */

@WebFilter(urlPatterns=("/*"))

public class EncodingFiter implements Filter {

    private String encoding = "UTF-8";// 默认字符集

    public EncodingFiter() {

        super();

    }

    public void destroy() {

    }

    public void doFilter(ServletRequest request, ServletResponse response,

            FilterChain chain) throws IOException, ServletException {

        HttpServletRequest req = (HttpServletRequest) request;

        HttpServletResponse res = (HttpServletResponse) response;

        // 中文处理必须放到 chain.doFilter(request, response)方法前面

        res.setContentType("text/html;charset=" + this.encoding);

        if (req.getMethod().equalsIgnoreCase("post")) {

            req.setCharacterEncoding(this.encoding);

        } else {

            Map map = req.getParameterMap();// 保存所有参数名=参数值(数组)的Map集合

            Set set = map.keySet();// 取出所有参数名

            Iterator it = set.iterator();

            while (it.hasNext()) {

                String name = (String) it.next();

                String[] values = (String[]) map.get(name);// 取出参数值[注：参数值为一个数组]

                for (int i = 0; i < values.length; i++) {

                    values[i] = new String(values[i].getBytes("ISO-8859-1"),

                            this.encoding);

                }

            }

        }

        chain.doFilter(request, response);

    }

    public void init(FilterConfig filterConfig) throws ServletException {

        String s = filterConfig.getInitParameter("encoding");// 读取web.xml文件中配置的字符集

        if (null != s && !s.trim().equals("")) {

            this.encoding = s.trim();

        }

    }

}

jsp页面显示(首页)：

尾页：

跳转：

如需要对另一个数据库表的信息进行分页，需修改dao层查询的语句，新建实体类；还有就是新建一个servlet和jsp页面。

完善上一篇后台显示对比的另一个实体类；

新建servlet和jsp页面。

jsp页面代码：

<%@ page language="java" contentType="text/html; charset=UTF-8"

    pageEncoding="UTF-8"%>

    <%@ page isELIgnored="false"%>

    <%@taglib prefix="z" uri="/yuan" %>

    <%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<html>

<head>

<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">

<title>Insert title here</title>

</head>

<body>

<h2>小说目录</h2>

    <br>

    <form action="/BlogServlet"

        method="post">

        书名：<input type="text" name="bookName"> <input type="submit"

            value="确定">

            <input type="hidden" name="pagination" value="false">

            <input type="hidden" name="rows" value="20">

    </form>

    <table border="1" width="100%">

        <tr>

            <td>编号</td>

            <td>名称</td>

        </tr>

        <c:forEach items="${blogList }" var="s">

            <tr>

                <td>${s.id }</td>

                <td>${s.bookName }</td>

            </tr>

            </c:forEach>

    </table>

    <z:Page pageBean="${pageBean }"></z:Page>

</body>

</html>

控制层Servlet：

package com.web;

import java.io.IOException;

import java.sql.SQLException;

import java.util.List;

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 com.yuan.dao.BlogDao;

import com.yuan.entity.Bookxyj;

import com.yuan.util.PageBean;

@WebServlet("/BlogServlet")

public class BlogServlet extends HttpServlet {

    /**

     *

     */

    private static final long serialVersionUID = 1L;

    private BlogDao blogDao = new BlogDao();

    @Override

    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        doPost(req, resp);

    }

    @Override

    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        Bookxyj xyj = new Bookxyj();

        xyj.setBookName(req.getParameter("bookName"));

        PageBean pageBean = new PageBean();

        try {

            pageBean.setRequest(req);

            List<Bookxyj> list = this.blogDao.list(xyj, pageBean);

            req.setAttribute("blogList", list);

            req.setAttribute("pageBean", pageBean);

            req.getRequestDispatcher("/blogList.jsp").forward(req, resp);

        } catch (InstantiationException | IllegalAccessException | SQLException e) {

            e.printStackTrace();

        }

        super.doPost(req, resp);

    }

}

谢谢观看！！！上一篇地址 https://www.cnblogs.com/ly-0919/p/11058942.html

码农公寓

通用分页的核心

.将上一次查询请求再发一次，只不过改变了页码。

本章重点：

相关文章