JavaWeb---資料分頁
阿新 • • 發佈：2018-11-29
資料分頁
這個東西就像是百度最下端的那個東西一樣的功能的，如下：
功能說明：
1、在不使用上方搜尋功能時，能夠檢視到所有的資料
2、下面的分頁功能將資料分成了許多頁，下方的分頁我規定只讓他顯示十頁(總共不止十頁，後面的要所在頁面移動才能夠顯示出其他的頁面，就像百度的分頁功能一樣的)，每一頁只顯示十行資料
3、上面的查詢功能也是借用了資料庫的模糊查詢功能實現的
當然了，這個小專案還需要使用到三個jar包：c3p0-0.9.1.2.jar、commons-dbutils-1.4.jar、mysql-connector-java-5.1.5-bin.jar
下面是程式碼：
配置檔案：c3p0-config.xml
<c3p0-config> <!-- 預設配置，如果沒有指定則使用這個配置 --> <default-config> <property name="driverClass">com.mysql.jdbc.Driver</property> <property name="jdbcUrl"> <![CDATA[jdbc:mysql://127.0.0.1:3306/mydata?useUnicode=true&characterEncoding=UTF-8]]> </property> <property name="user">root</property> <property name="password"></property> <!-- 初始化池大小 --> <property name="initialPoolSize">2</property> <!-- 最大空閒時間 --> <property name="maxIdleTime">30</property> <!-- 最多有多少個連線 --> <property name="maxPoolSize">10</property> <!-- 最少幾個連線 --> <property name="minPoolSize">2</property> <!-- 每次最多可以執行多少個批處理語句 --> <property name="maxStatements">50</property> </default-config> <!-- 命名的配置 --> <named-config name="hncu"> <property name="driverClass">com.mysql.jdbc.Driver</property> <property name="jdbcUrl">jdbc:mysql://127.0.0.1:3306/mydb</property> <property name="user">root</property> <property name="password"></property> <property name="acquireIncrement">5</property><!-- 如果池中資料連線不夠時一次增長多少個 --> <property name="initialPoolSize">100</property> <property name="minPoolSize">50</property> <property name="maxPoolSize">1000</property> <property name="maxStatements">0</property> <property name="maxStatementsPerConnection">5</property> <!-- he's important, but there's only one of him --> </named-config> </c3p0-config>
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%> <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <title>PagesDivided</title> </head> <body> <a href="<c:url value='PageServlet2'/>">資料分頁的分頁</a> </body> </html>
show2.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>showDividedPage</title>
<link rel="stylesheet" href="<c:url value='/css/table.css'/>"/>
<script type="text/javascript">
function change(obj){
window.location.href="<c:url value='/PageServlet2?page='/>"+obj.value;
}
</script>
</head>
<body>
<h3>資料查詢</h3>
<form action='<c:url value="/PageServlet2"/>' method="post">
ID:<input type="text" name="id" value="${stud.id}"/>
Name:<input type="text" name="name" value="${stud.name}"/>
<input type="submit" value="模糊查詢"/>
</form>
<hr/>
<h3 align="center">當前頁面內容</h3>
<table>
<tr><th>學號</th><th>姓名</th></tr>
<c:forEach items="${result.datas}" var="map">
<tr>
<td>${map.id}</td>
<td>${map.name}</td>
</tr>
</c:forEach>
</table>
<br/><br/>
<c:if test="${1!=result.currentPage}">
<a href="<c:url value='/PageServlet2?page=${result.currentPage-1}'/>">上一頁</a>
</c:if>
<c:forEach begin="${showStart}" end="${showEnd}" var="idx">
<c:if test="${idx==result.currentPage}">
${idx}
</c:if>
<c:if test="${idx!=result.currentPage}">
<span id="unselectedPage">
<a href="<c:url value='/PageServlet2?page=${idx}'/>">${idx}</a>
</span>
</c:if>
</c:forEach>
<c:if test="${result.pageCount!=result.currentPage}">
<a href="<c:url value='/PageServlet2?page=${result.currentPage+1}'/>">下一頁</a>
</c:if>
<select onchange="change(this)">
<c:forEach begin="1" end="${result.pageCount}" var="idx">
<option <c:if test="${idx==result.currentPage}">selected</c:if> value="${idx}">
第${idx}頁
</option>
</c:forEach>
</select>
</body>
</html>table.css
table{
clear:left;
border: 1px solid blue;
width:500px;
border-collapse: collapse;
margin: auto;
}
td{
border: 1px solid blue;
text-align: center;
}
th{
border: 1px solid blue;
}
body{
text-align: center;
}
a{
text-decoration: none;
}
#unselectedPage{
border: 1px solid blue;
width:500px;
margin: auto;
}公共類C3p0Pool.java
package cn.hncu.pubs;
import java.sql.Connection;
import java.sql.SQLException;
import javax.sql.DataSource;
import com.mchange.v2.c3p0.ComboPooledDataSource;
//我們的這個包裝，只是為了把c3p0池做成讓每個執行緒(客戶端)獲得的是同一個連線，方便做b/s框架下的事務
public class C3p0Pool {
private static DataSource pool;
private static ThreadLocal<Connection> t=new ThreadLocal<Connection>();
static {
pool=new ComboPooledDataSource();
}
public static DataSource getDataSource(){
return pool;
}
public static Connection getConnection() throws SQLException{
Connection con=t.get();
if (con==null){
con=pool.getConnection();
t.set(con);
}
return con;
}
}DAO層
介面：IPageDAO2.java
package cn.hncu.page2.dao;
import java.util.Map;
import cn.hncu.page2.domain.Stud;
public interface IPageDAO2 {
public Map<String, Object> query(Integer pageNo, Stud stud) throws Exception;
}
package cn.hncu.page2.dao;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.MapListHandler;
import org.apache.commons.dbutils.handlers.ScalarHandler;
import cn.hncu.page2.domain.Stud;
import cn.hncu.pubs.C3p0Pool;
public class PageJdbc2 implements IPageDAO2 {
private final int pageSize=10;
@Override
public Map<String, Object> query(Integer pageNo, Stud stud) throws Exception {
Map<String, Object> result=new HashMap<String, Object>();
//總行數
String sql="select count(1) from dbutilsstud where 1=1 ";//查總行數
String sql2="select * from dbutilsstud where 1=1 ";//查內容
if (stud.getId()!=null&&stud.getId().trim().length()!=0){
sql+="and id like '%"+stud.getId()+"%'";
sql2+="and id like '%"+stud.getId()+"%'";
}
if (stud.getName()!=null&&stud.getName().trim().length()!=0){
sql+="and name like '%"+stud.getName()+"%'";
sql2+="and name like '%"+stud.getName()+"%'";
}
QueryRunner run=new QueryRunner(C3p0Pool.getDataSource());
int rows=Integer.parseInt(""+run.query(sql, new ScalarHandler()));
//總頁數
int pageCount=rows/pageSize + (rows%pageSize==0 ? 0:1);
result.put("pageCount", pageCount);
//分頁面內容
int startNo=(pageNo-1)*pageSize;
sql2=sql2+" limit "+startNo+", "+pageSize;
List<Map<String, Object>> datas=run.query(sql2, new MapListHandler());
result.put("datas", datas);
return result;
}
}service層
介面：IPageService2.java
package cn.hncu.page2.service;
import java.util.Map;
import cn.hncu.page2.domain.Stud;
public interface IPageService2 {
public Map<String, Object> query(Integer pageNo, Stud stud) throws Exception;
}
package cn.hncu.page2.service;
import java.util.Map;
import cn.hncu.page2.dao.IPageDAO2;
import cn.hncu.page2.dao.PageJdbc2;
import cn.hncu.page2.domain.Stud;
public class PageServiceImpl2 implements IPageService2 {
//注入dao
IPageDAO2 dao=new PageJdbc2();
@Override
public Map<String, Object> query(Integer pageNo, Stud stud) throws Exception {
return dao.query(pageNo, stud);
}
}servlet ：PageServlet2.java
package cn.hncu.page2.servlet;
import java.io.IOException;
import java.util.Map;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import cn.hncu.page2.domain.Stud;
import cn.hncu.page2.service.IPageService2;
import cn.hncu.page2.service.PageServiceImpl2;
public class PageServlet2 extends HttpServlet {
//注入service
IPageService2 service=new PageServiceImpl2();
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doPost(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String pageNo=request.getParameter("page");
if (pageNo==null||pageNo.trim().length()==0){
pageNo="1";
}
Stud stud=null;
if (request.getMethod().equalsIgnoreCase("GET")){
stud=(Stud) request.getSession().getAttribute("stud");
if (stud==null){
stud=new Stud();
}
} else {
stud=new Stud();
String id=request.getParameter("id");
String name=request.getParameter("name");
stud.setId(id);
stud.setName(name);
request.getSession().setAttribute("stud", stud);
}
try {
Integer iPageNo=Integer.parseInt(pageNo);
Map<String, Object> result=service.query(iPageNo,stud);
//給結果集補一個數據: currentPage
result.put("currentPage", iPageNo);
//把結果集放入容器中
request.setAttribute("result", result);
int showSize=10;
int showStart=0;
int showEnd=0;
int pageCount=Integer.parseInt(""+result.get("pageCount"));
if (pageCount<showSize){
showStart=1;
showEnd=pageCount;
} else {
if (iPageNo<=(showSize/2+(showSize%2==0?0:1))){
showStart=1;
showEnd=showSize;
} else {
showStart=iPageNo-showSize/2;
showEnd=showStart+showSize-1;
}
if (showEnd>pageCount){
showEnd=pageCount;
showStart=showEnd-showSize+1;
}
}
request.setAttribute("showStart", showStart);
request.setAttribute("showEnd", showEnd);
//轉到結果頁面
request.getRequestDispatcher("/jsps/show2.jsp").forward(request, response);
} catch (NumberFormatException e) {
throw new RuntimeException("當前頁格式轉換錯誤", e);
} catch (Exception e) {
e.printStackTrace();
}
}
}值物件層：Stud.java
package cn.hncu.page2.domain;
public class Stud {
private String id;
private String name;
public Stud() {
}
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((id == null) ? 0 : id.hashCode());
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
Stud other = (Stud) obj;
if (id == null) {
if (other.id != null)
return false;
} else if (!id.equals(other.id))
return false;
return true;
}
}
這個小專案我是放在了page2這個包裡面的，page1是這個專案的另一個版本，就沒貼上來了；另外下面的show.jsp也是給另一個用的，這個專案使用的是show2.jsp
