struts分页的一种实现！(一）

    看到大家对struts的学习热情很高，而且这方面的资料很少，看着大家很累，所以发发善心，看到很好的一种分页方法，就贴出来大家共同分享！（原作在javaworld),有不完善的地方，希望大家改正！！！

使用一个页面控制类，它记录页面信息，如上页，下页，当前页等。在查询的Action中，将这个控制类和查询条件一起传递给数据库访问bean，然后将这两个参数保存在用户session中。在分页控制Action中，利用接收到的分页参数调用数据库访问的bean.

 (1)分页控制类

package com.tower.util;
public class PageController {
    int totalRowsAmount; file://总行数
    boolean rowsAmountSet; file://是否设置过totalRowsAmount
    int pageSize=2;   file://每页行数
    int currentPage=1; file://当前页码
    int nextPage;
    int previousPage;
    int totalPages;  file://总页数
    boolean hasNext;  file://是否有下一页
    boolean hasPrevious; file://是否有前一页
    String description;
    int pageStartRow;
    int pageEndRow;
   
    public PageController(int totalRows){
  setTotalRowsAmount(totalRows);
    }
    public PageController(){}
 public void setTotalRowsAmount(int i) {
  if(!this.rowsAmountSet){
   totalRowsAmount = i;
   totalPages=totalRowsAmount/pageSize+1;
      setCurrentPage(1);
   this.rowsAmountSet=true;
  }
  
 }
 public void setCurrentPage(int i) {
  currentPage = i;
  nextPage=currentPage+1;
  previousPage=currentPage-1;
  file://计算当前页开始行和结束行
  if(currentPage*pageSize<totalRowsAmount){
      pageEndRow=currentPage*pageSize;
      pageStartRow=pageEndRow-pageSize+1;
     
  }else{
      pageEndRow=totalRowsAmount;
      pageStartRow=pageSize*(totalPages-1)+1;
  }
  if (nextPage>totalPages){
      hasNext=false;
  }else{
   hasNext=true;
  }
  if(previousPage==0){
     hasPrevious=false;
  }else{
   hasPrevious=true;
  };
  System.out.println(this.description());
 }
 public int getCurrentPage() {
  return currentPage;
 }
 public boolean isHasNext() {
  return hasNext;
 }
 public boolean isHasPrevious() {
  return hasPrevious;
 }
 public int getNextPage() {
  return nextPage;
 }
 public int getPageSize() {
  return pageSize;
 }
 public int getPreviousPage() {
  return previousPage;
 }
 public int getTotalPages() {
  return totalPages;
 }
 public int getTotalRowsAmount() {
  return totalRowsAmount;
 }
 public void setHasNext(boolean b) {
  hasNext = b;
 }
 public void setHasPrevious(boolean b) {
  hasPrevious = b;
 }
 public void setNextPage(int i) {
  nextPage = i;
 }
 public void setPageSize(int i) {
  pageSize = i;
 }
 public void setPreviousPage(int i) {
  previousPage = i;
 }
 public void setTotalPages(int i) {
  totalPages = i;
 }
 public int getPageEndRow() {
  return pageEndRow;
 }
 public int getPageStartRow() {
  return pageStartRow;
 }

 public String getDescription(){
    String description="Total:"+this.getTotalRowsAmount()+
    " items "+this.getTotalPages() +" pages";
//    this.currentPage+" Previous "+this.hasPrevious +
//    " Next:"+this.hasNext+
//    " start row:"+this.pageStartRow+
//    " end row:"+this.pageEndRow;
    return description;
 }
 
 public String description(){
    String description="Total:"+this.getTotalRowsAmount()+
    " items "+this.getTotalPages() +" pages,Current page:"+
    this.currentPage+" Previous "+this.hasPrevious +
    " Next:"+this.hasNext+
    " start row:"+this.pageStartRow+
    " end row:"+this.pageEndRow;
    return description;
 }
 
 
 public static void main(String args[]){
  PageController pc=new PageController(3);
        System.out.println(pc.getDescription());
//        pc.setCurrentPage(2);
//  System.out.println(pc.description());
//  pc.setCurrentPage(3);
//  System.out.println(pc.description());
 }

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