通用分页二
这次主要是将分页体现在JSP页面上，上一篇只是完成后台的分页
首先我们来完善一下pagebean页面的内容
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) { //保存上一次请求所携带得参数 this.setPaMap(req.getParameterMap()); this.setUrl(req.getRequestURI().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数据 this.setRows(req.getParameter("rows")); this.setPage(req.getParameter("page")); } public void setPage(String page) { this.page=StringUtils.isNotBlank(page)?Integer.valueOf(page):this.page; } public void setPagination(String pagination) { this.pagination=StringUtils.isNotBlank(pagination)?!"false".equals(pagination):this.pagination; } 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 + "]"; } /** * 获取最大的页码数 * @return */ public int getMaxPage() { return this.total%this.rows==0 ? this.total/this.rows : this.total/this.rows+1; } /** * 获取下一页 * @return */ public int getNextPage() { return this.page < this.getMaxPage() ? this.page+1:this.page; } /** * 获取上一页 * @return */ public int getpreviousPage() { return this.page>1 ? this.page-1:this.page; } }
接下来在新建servlet的方法
BookServlet
package com.web; import java.io.IOException; import java.sql.SQLException; import java.util.List; import java.util.Map; import javax.jws.WebService; import javax.servlet.ServletException; import javax.servlet.annotation.WebFilter; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import com.entity.Book; import com.jt.dao.BookDao; import com.util.PageBean; @WebServlet("/bookServlet") public class BookServlet extends HttpServlet { private static final long serialVersionUID = 6304839939800249916L; private BookDao bookDao=new BookDao(); @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { // TODO Auto-generated method stub doPost(req, resp); } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { // TODO Auto-generated method stub String bname=req.getParameter("bname"); Book book=new Book(); book.setBname(bname); // Map<String,String[]> parameterMap=req.getParameterMap(); // StringBuffer url= req.getRequestURL(); PageBean pageBean=new PageBean(); try { pageBean.setRequest(req); List<Book> list= this.bookDao.list(book, pageBean); req.setAttribute("bookList", list); req.setAttribute("pageBean",pageBean); req.getRequestDispatcher("/BookList.jsp").forward(req, resp); } catch (InstantiationException | IllegalAccessException | SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } } }
下面就是PageTag类了
也是我们的标签类
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.util.PageBean; public class PageTag extends BodyTagSupport { private static final long serialVersionUID = -553969530960334073L; 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() { // TODO Auto-generated method stub StringBuilder sb=new StringBuilder(); //拼接下一次发送请求所要提交得隐藏得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namepage得参数，但是改参数在前面以及单独赋值 //为什么要单独赋值？因为上一次请求时第一页得数据，下一次可能时第二页，以后这前后请求page对应得值不一样，需要单独赋值 if(!"page".equals(entry.getKey())) { // <input type='hidden' name='hobby' value='1'> // <input type='hidden' name='hobby' value='2'> //[1,2] 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.getNextPage()+")'>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>"); //拼接分页所需要得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(); } }
还有一个就是我们的过滤器也是非常重要的
EncodingFiter
package com.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(); } } }
现在去jsp页面传值就可以了
把我们自定义的标签导进去
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %> <%@taglib prefix="z" uri="/jt" %> <!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="${pageContext.request.contextPath}/bookServlet" method="post"> 书名：<input type="text" name="bname"> <input type="submit" value="确定"> </form> <table border="1" width="100%"> <tr> <td>编号</td> <td>名称</td> <td>价格</td> </tr> <c:forEach items="${bookList }" var="b"> <tr> <td>${b.bid }</td> <td>${b.bname }</td> <td>${b.price }</td> </tr> </c:forEach> </table> <z:page pageBean="${pageBean }"></z:page> </body> </html>
大家肯定会说不用配XML？我采用的是一种更加方便的方法
@WebServlet("/bookServlet")
@WebFilter(urlPatterns="/*")
就这2条代码，和XML里面的配置效果是一样的，这样也方便点
来让我们看下运行结果
首页
下一页
尾页
查询
跳转
接下来我们就来试试我们的通用分页
我用另一个数据表来调用下
新建servlet类
BlogServlet
package com.web; import java.io.IOException; import java.sql.SQLException; import java.util.List; import javax.servlet.ServletException; import javax.servlet.annotation.WebFilter; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import com.entity.Blog; import com.jt.dao.BlogDao; import com.util.PageBean; @WebServlet("/blogServlet") public class BlogServlet extends HttpServlet { private BlogDao blogDao=new BlogDao(); @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { // TODO Auto-generated method stub doPost(req, resp); } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { // TODO Auto-generated method stub Blog blog=new Blog(); blog.setBookname(req.getParameter("bookname")); PageBean pageBean=new PageBean(); try { List<Blog> list = this.blogDao.list(blog, pageBean); req.setAttribute("blogList",list); req.setAttribute("pageBean",pageBean); req.getRequestDispatcher("/BlogList.jsp").forward(req, resp); } catch (InstantiationException | IllegalAccessException | SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } } }
jsp页面
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %> <%@taglib prefix="z" uri="/jt" %> <!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="${pageContext.request.contextPath}/blogServlet" method="post"> 书名：<input type="text" name="bname"> <input type="submit" value="确定"> </form> <table border="1" width="100%"> <tr> <td>编号</td> <td>名称</td> </tr> <c:forEach items="${blogList }" var="b"> <tr> <td>${b.id }</td> <td>${b.bookname }</td> </tr> </c:forEach> </table> <z:page pageBean="${pageBean }"></z:page> </body> </html>
改下foreach里面的就可以了，通用分页调用就是这么简单了
