通用分页jsp页面显示
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 = 1;// 页码 private int rows = 10;// 页大小 private int total = 0;// 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 - 1) * 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 == 0 ? this.total / this.rows : this.total / this.rows+1; } /** * 下一页 * @return */ public int getNexPage() { return this.page < this.getMaxPage() ? this.page+1 : this.page; } /** * 上一页 * @return */ public int getPreviousPage() { return this.page > 1 ? this.page-1 : 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="${pageContext.request.contextPath}/bookServlet.action" method="post"> 书名：<input type="text" name="bname"> <input type="submit" value="确定"> <input type="hidden" name="pagination" value="false"> <input type="hidden" name="rows" value="20"> </form> <table border="1" width="100%"> <tr> <td>编号</td> <td>名称</td> <td>价格</td> </tr> <c:forEach items="${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 <a "); sb.append(" href='javascript:gotoPage(1)'>首页</a> <a"); sb.append(" href='javascript:gotoPage("+pageBean.getPreviousPage()+")'>上一页</a> <a"); sb.append(" href='javascript:gotoPage("+pageBean.getNexPage()+")'>下一页</a> <a"); sb.append(" href='javascript:gotoPage("+pageBean.getMaxPage()+")'>尾页</a> <input type='text'"); sb.append(" id='skipPage'"); sb.append(" style='text-align: center; font-size: 12px; width: 50px;'> <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)：
下一页：
尾页：
上一页：
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
