struts中的分页实例

一、struts-config.xml配置，主要是配数据库,这里用access。
<?xml version="1.0" encoding="ISO-8859-1" ?>

<!DOCTYPE struts-config PUBLIC
          "-//Apache Software Foundation//DTD Struts Configuration 1.2//EN"
          "http://jakarta.apache.org/struts/dtds/struts-config_1_2.dtd">


<struts-config>
<data-sources>
   <data-source key="dataSource" type="org.apache.commons.dbcp.BasicDataSource">
            <set-property property="driverClassName" value="sun.jdbc.odbc.JdbcOdbcDriver" />
            <set-property property="url" value="jdbc:odbc:page" />
            <set-property property="username" value="admin" />
            <set-property property="password" value="" />
            <set-property property="maxActive" value="20" />
            <set-property property="maxWait" value="5000" />
            <set-property property="defaultAutoCommit" value="true" />
            <set-property property="defaultReadOnly" value="false" />
            <set-property property="validationQuery" value="SELECT 1" />
            <set-property property="removeAbandoned" value="true" />
            <set-property property="removeAbandonedTimeout" value="120" />            
            <set-property property="encoding" value="false" />            
        </data-source>

</data-sources>
  <form-beans>
  </form-beans>
  <global-forwards>
  </global-forwards>

  <action-mappings>
  <action path="/page" type="page.DataSourceAction" scope="request">
  <forward name="success" path="/pagetest.jsp"/>
  </action>
  </action-mappings>

  <controller>
  </controller>
</struts-config>

二、Action类
用 page.do?start=1 来显示第一个页面  
参数说明：  
  list：信息列表  
  start：开始位置  
  page：每页显示的信息数目  
  pages: 总页数
  previous：上页开始位置  
  next：下页开始位置  

package page;
import org.apache.struts.action.*;
import javax.servlet.http.*;

import java.util.*;
import javax.sql.*;
import java.sql.*;
import bean.*;

public class DataSourceAction extends Action {

public DataSourceAction(){}
  
public ActionForward execute(ActionMapping mapping, ActionForm form, HttpServletRequest request,
HttpServletResponse response) throws Exception {    
  try{
      DataSource ds=this.getDataSource(request,"dataSource");    
      Connection con = ds.getConnection();
      Statement stmt = con.createStatement();
      ResultSet resultSet = stmt.executeQuery("select count(*) from book" );  
      resultSet.next();  
      int data_num=resultSet.getInt(1);  
      int start=1;
      int page = 4; //每页的记录数。
      int pages=data_num/page;
      if(data_num%page!=0)
         pages++;
      if(request.getParameter("start")!=null)
          start = Integer.parseInt(request.getParameter("start"));  
      if(request.getParameter("go")!=null){
                int go = Integer.parseInt(request.getParameter("go"));  
                if(go<=1)
                  start=1;
                else if(go>pages)
                  start=(pages-1)*page+1;
                else  
                   start=(go-1)*page+1;
       }  
      
      String sql = "SELECT * FROM book where id>="+start+" and id<"+(start+page);
      resultSet = stmt.executeQuery(sql);  
      ArrayList list = new java.util.ArrayList();  
      while(resultSet.next())
      {  
        int id=resultSet.getInt("id");
        String name = resultSet.getString("name");
        String author = resultSet.getString("author");
        String price = resultSet.getString("price");
        System.out.println("开始数据封装：name="+name+"author="+author+"price="+price);
        Book book= new Book(id,name,author,price);        
        list.add(book);
      }
    con.close();
    request.setAttribute("pages",new Integer(pages));
    request.setAttribute("list",list);
    //request.setAttribute("start", new Integer(start));  
    request.setAttribute("page", new Integer(page));  

        // if there is a previous page, set the previous variable  
        int previous = start-page;  
        if ( previous>=0 ){  
            request.setAttribute("previous", new Integer(previous));  
            System.out.println ("previous:" + previous);  
        }  

        // if there is a next page, set the next variable  
        int next = start+page;  
        if ( next<=data_num ){  
            request.setAttribute("next", new Integer(next));  
            System.out.println ("next:" + next);  
        }  

   }catch(SQLException e){
          e.printStackTrace();
          System.out.println("数据库连接出现异常");
      }  
    
             return (mapping.findForward("success"));
  }  
}


三、bean类Book.java
package bean;
import java.sql.*;
import java.util.ArrayList;
public class Book {
int id;
private String bookname; //书名
private String author;   //作者
private String price;    //价格
  
public Book(int id,String name,String author,String price){
this.id=id;
this.bookname=name;
this.author=author;
this.price=price;
}

public int getId(){  
        return id;  
    }  

public String getAuthor() {
  return author;
}

public void setAuthor(String author) {
  this.author = author;
}

public String getBookname() {
  return bookname;
}

public void setBookname(String bookname) {
  this.bookname = bookname;
}
  
public String getPrice(){
     return this.price;  
}
  
public void setPrice(String price){
     this.price=price;  
}
  
}
四、分页的jsp页面pagetest.jsp,用了jstl中的c标记。
<%@ page contentType="text/html; charset=gb2312" language="java"%>
<%@ page import="java.util.*" %>
<%@ page import="bean.*" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jstl/core" %>
<%@ taglib uri="/tags/struts-bean" prefix="bean" %>
<%@ taglib uri="/tags/struts-html" prefix="html" %>
<%@ taglib uri="/tags/struts-logic" prefix="logic" %>

<logic:iterate id="book" name="list" type="bean.Book">  
            <br><html:link  
                    paramId="id" paramName="book" paramProperty="id"  
                    page="/messagedetail.do">  
                    <bean:write name="book" property="bookname" />  
                </html:link>  
</logic:iterate>  

<form action="/TestPage/page.do">
   <logic:present name="previous">  
            <html:link  
                    paramId="start" paramName="previous"  
                    page="/page.do">  
                    上一页  
                </html:link>  
   </logic:present>  

   <logic:present name="next">  
              <html:link  
                    paramId="start" paramName="next"  
                    page="/page.do">  
                    下一页  
                </html:link>  
   </logic:present>  

每页<c:out value="${page}"/>条记录,共<c:out value="${pages}"/>页  跳到<input type="text"  name="go" size="3" maxlength="30" >
<input type="submit" value="go" >
</form>