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mvc之通用分頁(二)

今天的任務：

1、補全servlet

2、頁面展示

3、了解分頁重要參數（page、rows、是否分頁、上一次請求、上一次的表單參數）

4、自定義分頁标簽

核心代碼如下：

PageBean:

package com.liyi.util;

import java.util.HashMap;
import java.util.Map;

import javax.servlet.http.HttpServletRequest;

/**
 * 分頁工具類
 *
 */
public class PageBean {
	private int page = 1;// 頁碼
	private int rows = 10;// 頁大小
	private int total = 0;// 總記錄數
	private boolean pagination = true;// 是否分頁
	
	private String url;
	private Map<String, String[]> paramMap = new HashMap<>();
	
	public void setRequest(HttpServletRequest req) {
		this.setPage(req.getParameter("page"));
		this.setRows(req.getParameter("rows"));
		this.setPagination(req.getParameter("pagination"));
		// getRequestURL擷取到浏覽器請求的全路徑
		this.setUrl(req.getRequestURL().toString());
		// getParameterMap可以擷取到一次url請求所攜帶的所有參數
		this.setParamMap(req.getParameterMap());
	}
	public void setPagination(String pagination) {
		if (StringUtils.isNotBlank(pagination)) {
			this.setPagination(!"false".equals(pagination));
		}
	}
	public void setRows(String rows) {
		if (StringUtils.isNotBlank(rows))
  		 this.setRows(Integer.valueOf(rows));
	}
	public void setPage(String page) {
	  if (StringUtils.isNotBlank(page)) {
		   this.setPage(Integer.valueOf(page));
		 }
	 }	

	public PageBean() {
	  super();
	 }
	 
	public String getUrl() {
	  return url;
	 }
	
	public void setUrl(String url) {
	  this.url = url;
	 }

	public Map<String, String[]> getParamMap() {
	  return paramMap;
	 }
	
	public void setParamMap(Map<String, String[]> paramMap) {
	  this.paramMap = paramMap;
	 }

	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;
	 }
	 
	 /**
	  * 獲得起始記錄的下标
	  * 
	  * @return
	  */
	 public int getStartIndex() {
	  return (this.page - 1) * this.rows;
	 }
	 
	 @Override
	 public String toString() {
	  return "PageBean [page=" + page + ", rows=" + rows + ", total=" + total + ", pagination=" + pagination + "]";
	 }
	 
	 /**
	  * 擷取到總頁數
	  * @return
	  */
	 public int getMaxPage() {
	  return this.total % this.rows == 0 ? 
	    this.total / this.rows : 
	     (this.total / this.rows) + 1;
	 }
	 
	 /**
	  * 擷取下一頁頁碼
	  * @return
	  */
	 public int getNextPage() {
	  return this.page < this.getMaxPage() ? this.page+1 : this.page;
	 }
	 
	 /**
	  * 擷取上一頁頁碼
	  * @return
	  */
	 public int getPreviousPage() {
	  return this.page > 1 ? this.page-1 : this.page;
	 }
	 }

PageTag.java:

package com.liyi.tags;
import java.io.IOException;
import java.util.Map;
import java.util.Map.Entry;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.tagext.BodyTagSupport;
import com.liyi.util.PageBean;
public class PageTag extends BodyTagSupport {
	 private static final long serialVersionUID = 2411829139570358249L;
	 private PageBean pageBean;
	 
	 @Override
	 public int doStartTag() throws JspException {
	  JspWriter out = pageContext.getOut();
	  try {
	   out.write(toHTML());
	  } catch (IOException e) {
	   e.printStackTrace();
	  }
	  return super.doStartTag();
	 }
	 public String toHTML() {
	  StringBuffer sb = new StringBuffer();
	  // 下一次請求送出到背景的表單html代碼拼接
	  sb.append("<form id='pageBeanForm' action='" + pageBean.getUrl() + "' method='post'>");
	  Map<String, String[]> paramMap = pageBean.getParamMap();
	  if (paramMap != null && paramMap.size() > 0) {
	   for (Entry<String, String[]> entry : paramMap.entrySet()) {
	    if (!"page".equals(entry.getKey())) {
	     for(String val : entry.getValue()) {
	      sb.append("<input type='hidden' name='" + entry.getKey() + "' value='" + val + "' >");
	     }
	    }
	   }
	  }
	  sb.append("<input type='hidden' name='page'>");
	  sb.append("</form>");
	  // 分頁條html代碼拼接
	  
	  sb.append("<div style='text-align: right; font-size: 12px;'>");
	  sb.append(" 每頁"+pageBean.getRows()+"條，共"+pageBean.getTotal()+"條，第"+pageBean.getPage()+"頁，共"+pageBean.getMaxPage()+"頁&nbsp;&nbsp;<a ");
	  sb.append(" href='javascript:gotoPage(1)'>首頁</a>&nbsp;&nbsp;<a");
	  sb.append(" href='javascript:gotoPage("+pageBean.getPreviousPage()+")'>上一頁</a>&nbsp;&nbsp;<a");
	  sb.append(" href='javascript:gotoPage("+pageBean.getNextPage()+")'>下一頁</a>&nbsp;&nbsp;<a");
	  sb.append(" href='javascript:gotoPage("+pageBean.getMaxPage()+")'>尾頁</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>");
	  
	  // 分頁所需要調用的js代碼
	  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('請輸入1~N的數字');");
	  sb.append("   return;");
	  sb.append("  }");
	  sb.append("  gotoPage(page);");
	  sb.append(" }");
	  sb.append("</script>");
	  
	  return sb.toString();
	 }
	 
	 public PageBean getPageBean() {
	  return pageBean;
	 }
	 
	 public void setPageBean(PageBean pageBean) {
	  this.pageBean = pageBean;
	 }
	}

BookServlet.java：

package com.liyi.web;

import java.io.IOException;
import java.sql.SQLException;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.liyi.dao.BookDao;
import com.liyi.entity.Book;
import com.liyi.util.PageBean;

public class BookServlet extends HttpServlet {
	 private BookDao bookDao = new BookDao();
	 private static final long serialVersionUID = -7654671804738498584L;
	 @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 pageBean = new PageBean();
	  pageBean.setRequest(req);
	  try {
	   List<Book> list = bookDao.list(book, pageBean);
	   req.setAttribute("bookList", list);
	   req.setAttribute("pagebean", pageBean);
	   req.getRequestDispatcher("bookList.jsp").forward(req, resp);
	  } catch (InstantiationException e) {
	   e.printStackTrace();
	  } catch (IllegalAccessException e) {
	   e.printStackTrace();
	  } catch (SQLException e) {
	   e.printStackTrace();
	  }
	 }
	}

z.tld:

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

<taglib xmlns="http://java.sun.com/xml/ns/j2ee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-jsptaglibrary_2_0.xsd"
    version="2.0">
    
  <description>z 1.1 core library</description>
  <display-name>z core</display-name>
  <tlib-version>1.1</tlib-version>
  <short-name>c</short-name>
  <uri>/z</uri>
  
  <tag>
   <!-- 标簽庫中的标簽名 -->
    <name>page</name>
    <!-- 标簽對應的助手類的全路徑名 -->
    <tag-class>com.liyi.tags.PageTag</tag-class>
    <!-- JSP -->
    <body-content>JSP</body-content>
    <attribute>
     <!-- 屬性名 -->
        <name>pageBean</name>
        <!-- 屬性值是否必填 -->
        <required>true</required>
        <!-- 是否支援表達式 -->
        <rtexprvalue>true</rtexprvalue>
    </attribute>
  </tag>
  
</taglib>

web.xml:

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

<web-app version="3.1" id="WebApp_ID" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee 

http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" xmlns="http://xmlns.jcp.org/xml/ns/javaee" 

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

<display-name>liyi_xml</display-name>

<filter>

<filter-name>encodingFiter</filter-name>

<filter-class>com.liyi.util.EncodingFiter</filter-class>

</filter>

<filter-mapping>

<filter-name>encodingFiter</filter-name>

<url-pattern>/*</url-pattern>

</filter-mapping>

<servlet>

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

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

</servlet>

<servlet-mapping>

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

<url-pattern>/bookServlet</url-pattern>

</servlet-mapping>

</web-app>

bookList.jsp:

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
    <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
    <%@ taglib uri="/z"  prefix="z" %>
<!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>小說目錄</h2>
 <br>
 <form action="${pageContext.request.contextPath}/bookServlet"
	  method="post">
	  <input type="hidden" name="pagination" value="false">
	  書名：<input type="text" name="bname"> <input type="submit"
	   value="确定">
 </form>
 <table  width="100%">
	  <tr>
		   <td>編号</td>
		   <td>名稱</td>
		   <td>價格</td>
	  </tr>
	  <c:forEach items="${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>

實作效果如下：

mvc之通用分頁(二)

好啦，今天的更新就到這了，喜歡點贊+轉發~

java mvc 通用分頁
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