說道Struts自然是不能離開MVC模式,分頁顯示也是如此.我不知道我的算法是不是算好的,也希望看過的朋友能發表一下自己的看法,下面簡單闡述一下主要的開發思路:

1)建立適當的模型組件,對應你要查詢數據庫中的表,這部分由熟悉的JavaBean來充當.并在其中建立數據庫查詢方法,該方法需要一個java.sql.Conntection類型的參數,并返回一個ArrayList,在本例中為Book.java,另外還有一個數據庫連接的Bean是SqlBean.java.

2)建立分頁所需要的模型組件,也是用JavaBean,通過Book提供的ArrayList來構造,這里用的是PageBean.java.

3)建立控制器組件,這部分由Struts的Action來實現,主要負責實例化Book,并利用返回的ArrayList對象,構造PageBean,以及接收由視圖傳遞來的action參數,從而在PageBean對象中調用不同的方法,該方法返回Book[]對象,最后將Book[]和PageBean放入到request中.本Action為PageListAction.java.

4)建立視圖組件,這部分JSP來實現,為了不出現JAVA代碼,使用Struts提供的標簽庫,主要負責從Request中取出剛剛放入的對象,通過反復調用Action以及action參數,而實現分頁顯示,是pagetest.jsp.

5)建立并配置struts-config.xml和web.xml文件.

6)建立數據庫.

我對代碼進行了實現,調試通過.如果大家有更好的用Struts實現分頁顯示的算法可以給我留言,代碼如下:

struts-config.xml文件如下,這里配置了一個接收haha的請求提交給PageListAction

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

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

<struts-config>

   <action-mappings>

       <action path="/haha"

               type="page.PageListAction"

               scope="request">

             <forward name="success" path="/pagetest.jsp"/>

       </action>

    </action-mappings>

   <message-resources parameter="ApplicationResources" />

</struts-config>

……………………………………………………………………………….

Web.xml文件如下,這里配置了Web的信息,基本都是由Eclipse完成的

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

<web-app xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="2.4" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee   http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">

   <servlet>

      <servlet-name>action</servlet-name>

      <servlet-class>org.apache.struts.action.ActionServlet</servlet-class>

      <init-param>

         <param-name>application</param-name>

         <param-value>ApplicationResources</param-value>

      </init-param>

      <init-param>

         <param-name>config</param-name>

         <param-value>/WEB-INF/struts-config.xml</param-value>

      </init-param>

      <init-param>

         <param-name>debug</param-name>

         <param-value>2</param-value>

      </init-param>

      <init-param>

         <param-name>detail</param-name>

         <param-value>2</param-value>

      </init-param>

      <load-on-startup>2</load-on-startup>

   </servlet>

   <servlet-mapping>

      <servlet-name>action</servlet-name>

      <url-pattern>*.do</url-pattern>

   </servlet-mapping>

   <welcome-file-list>

     <welcome-file>index.jsp</welcome-file>

     </welcome-file-list>

</web-app>

…………………………………………………………………………

這個是控制器Action類

package page;

import org.apache.struts.action.*;

import javax.servlet.http.*;

import bean.Book;

import java.util.*;

import javax.sql.DataSource;

public class PageListAction extends Action {

    ArrayList arrayList=new ArrayList();

    PageBean pd;

    public ActionForward execute(ActionMapping mapping,

                                 ActionForm form,

                                 HttpServletRequest request,

                                 HttpServletResponse response)

    throws Exception {

        String action;

        action=request.getParameter("action");

        if(action==null||action.equals("null")) {

            try {

                arrayList=Book.getAllBook();

            }

            catch(Exception e) {

                e.printStackTrace();

            }

            pd=new PageBean(arrayList);

            Book[] books=pd.getBooks();

            request.setAttribute("result",books);

            request.setAttribute("page",pd);

        }

        else {

            if(action=="nextPage"||action.equals("nextPage")) {

                Book[] books=pd.getNextPage();

                request.setAttribute("result",books);

                request.setAttribute("page",pd);

            }

            if(action=="previousPage"||action.equals("previousPage")) {

                Book[] books=pd.getPreviousPage();

                request.setAttribute("resule",books);

                request.setAttribute("page",pd);

            }

        }

        return mapping.findForward("success");

    }

}

………………………………………………………………………………….

這個是pagebean類,主要負責分頁算法和邏輯處理

package page;

import bean.Book;

import java.util.*;

public class PageBean {

    int currentPage=1;//當前頁數

    public int totalPages=0;//總頁數

    int pageRecorders=2;//每頁顯示數

    int totalRows=0;//總數據數

    int pageStartRow=0;//每頁的起始數

    int pageEndRow;//每頁的終止數

    boolean hasNextPage=false;//是否有下一頁

    boolean hasPreviousPage=false;//是否有前一頁

    ArrayList arrayList;

    Iterator it;

    public PageBean(ArrayList arrayList) {

        this.arrayList=arrayList;

        totalRows=arrayList.size();

        it=arrayList.iterator();

        hasPreviousPage=false;

        currentPage=1;

        if((totalRows%pageRecorders)==0) {

            totalPages=totalRows/pageRecorders;

        }

        else {

            totalPages=totalRows/pageRecorders+1;

        }

        if(currentPage>=totalPages) {

            hasNextPage=false;

        }

        else {

            hasNextPage=true;

        }

        if(totalRows<pageRecorders) {

            this.pageStartRow=0;

            this.pageEndRow=totalRows;

        }

        else {

            this.pageStartRow=0;

            this.pageEndRow=pageRecorders;

        }

    }

    public void setCurrentPage(int currentPage) {

        this.currentPage=currentPage;

    }

    public void setPageRecorders(int pageRecorders) {

        this.pageRecorders=pageRecorders;

    }

    public void setHasNextPage(boolean hasNextPage) {

        this.hasNextPage=hasNextPage;

    }

    public void setHasPreviosPage(boolean hasPreviosPage) {

        this.hasPreviousPage=hasPreviousPage;

    }

    public String getCurrentPage() {

        return this.toString(currentPage);

    }

    public String getTotalPages() {

        return this.toString(totalPages);

    }

    public String getTotalRow() {

        return this.toString(totalRows);

    }

    public int getPageRecorders() {

        return pageRecorders;

    }

    public int getPageEndRow() {

        return pageEndRow;

    }

    public int getPageStartRow() {

        return pageStartRow;

    }

    public boolean isHasNextPage() {

        return hasNextPage;

    }

    public boolean isHasPreviousPage() {

        return hasPreviousPage;

    }

    public Book[] getNextPage() {

        currentPage=currentPage+1;

        if((currentPage-1)>0) {

            hasPreviousPage=true;

        }

        else {

            hasPreviousPage=false;

        }

        if(currentPage>=totalPages) {

            hasNextPage=false;

        }

        else {

            hasNextPage=true;

        }

        Book[] books=getBooks();

        return books;

    }

    public Book[] getPreviousPage() {

        currentPage=currentPage-1;

        if(currentPage==0) {

            currentPage=1;

        }

        if(currentPage>=totalPages) {

            hasNextPage=false;

        }

        else {

            hasNextPage=true;

        }

        if((currentPage-1)>0) {

            hasPreviousPage=true;

        }

        else {

            hasPreviousPage=false;

        }

        Book[] books=getBooks();

        return books;

    }

    public Book[] getBooks() {

        if(currentPage*pageRecorders<totalRows) {

            pageEndRow=currentPage*pageRecorders;

            pageStartRow=pageEndRow-pageRecorders;

        }

        else {

            pageEndRow=totalRows;

            pageStartRow=pageRecorders*(totalPages-1);

        }

        Book[] books=new Book[pageEndRow-pageStartRow+1];

        int j=0;

        for(int i=pageStartRow;i<pageEndRow;i++) {

            Book book=(Book)arrayList.get(i);

            books[j++]=book;

        }

        return books;

    }

    public String toString(int temp) {

        String str=Integer.toString(temp);

        return str;

    }

}

……………………………………………………………………………….

Book類,負責查詢數據庫,把結果放到一個ArrayList中

package bean;

import java.sql.*;

import java.util.ArrayList;

public class Book {

    private String bookname;

    private String author;

    private String price;

    public Book(String name,String author,String price) {

        this.bookname=name;

        this.author=author;

        this.price=price;

    }

    public void setBookname(String bookname) {

        this.bookname=bookname;

    }

    public void setAuthor(String Author) {

        this.author=author;

    }

    public void setPrice(String price) {

        this.price=price;

    }

    public String getBookname() {

        return bookname;

    }

    public String getAuthor() {

        return author;

    }

    public String getPrice() {

        return price;

    }

    public static ArrayList getAllBook() throws Exception {

        String sql="select * from book";

        SqlBean sq=new SqlBean();

        ArrayList arrayList=new ArrayList();

        try

        {

            ResultSet resultSet=sq.select(sql);

            while(resultSet.next()) {

                String name=resultSet.getString("name");

                String author=resultSet.getString("author");

                String price=resultSet.getString("price");

                Book book=new Book(name,author,price);

                arrayList.add(book);

            }

            resultSet.close();

        }

        catch(SQLException e)

        {

            System.out.println("數據庫錯誤"+e.toString());

        }

        return arrayList;

    }

}

………………………………………………………………………………..

這個是SqlBook,負責和數據庫建立一個連接的Bean

package bean;

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.ResultSet;

import java.sql.Statement;

public class SqlBean {

    String url="jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=eBookStore";

    Connection con=null;

    Statement sta=null;

    public SqlBean() {

        try

        {

            Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");

            con=DriverManager.getConnection(url,"sa","");

            sta=con.createStatement();

        }

        catch(Exception e)

        {

            System.out.println("連接錯誤"+e.toString());

        }

    }

    public ResultSet select(String selects) throws Exception

    {

        return sta.executeQuery(selects);

    }

}

…………………………………………………………………………

這個是負責顯示分頁的JSP頁.pagetest.jsp

<%@ taglib uri="/WEB-INF/struts-html.tld" prefix="html"%>

<%@ taglib uri="/WEB-INF/struts-bean.tld" prefix="bean"%>

<%@ taglib uri="/WEB-INF/struts-logic.tld" prefix="logic"%>

<%@ page contentType="text/html;charset=gb2312"%>

<html:html locale="true">

  <head>

  </head>

  <body>

    <table border="1">

      <tr><th>書名</th><th>作者</th><th>價格</th></tr>

      <logic:present name="result">

        <logic:iterate id="book" name="result" type="bean.Book">

          <logic:present name="book">

            <tr>

              <td><bean:write name="book" property="bookname"/></td>

              <td><bean:write name="book" property="author"/></td>

              <td><bean:write name="book" property="price"/></td>

            </tr>

          </logic:present>

        </logic:iterate>

      </logic:present>

    </table>

    <logic:present name="page">

      <logic:equal name="page" property="hasNextPage" value="true">

        <html:link page="/haha.do?action=nextPage">nextPage</html:link>

      </logic:equal>

      <logic:equal name="page" property="hasPreviousPage" value="true">

        <html:link page="/haha.do?action=previousPage">previousPage</html:link>

      </logic:equal>

             共分<bean:write name="page" property="totalPages"/>頁顯示,當前是

                 <bean:write name="page" property="currentPage"/>頁.

    </logic:present>

  </body>

</html:html>

…………………………………………………………………………………

這個是首頁的JSP頁面,只有一個連接.提交一個haha.do的請求

<%@ taglib uri="/WEB-INF/struts-html.tld" prefix="html"%>

<%@ page contentType="text/html;charset=gb2312" language="java"%>

<html:html>

  <head>

  </head>

  <body>

    <html:link action="haha.do">GotoPage</html:link>

  </body>

</html:html>