Java常用工具类集合（四）

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package com.util;

/**
* 分页工具类
*
*/
public class SharePager {
private int totalRows; //总行数
private int pageSize = 20; //每页显示的行数
private int currentPage; //当前页号
private int totalPages; //总页数
private int startRow; //当前页在数据库中的起始行

/**
* 默认构造函数
*/
public SharePager()
{

}

/**默认每页10行
* @param totalRows
*/
public SharePager(int totalRows)
{
this.totalRows = totalRows;

totalPages =(int) Math.ceil((double)totalRows / (double)pageSize);
startRow = 0;
}

/**可自定义每页显示多少页
* @param totalRows
* @param pageSize
*/
public SharePager(int totalRows, int pageSize)
{
this.totalRows = totalRows;
this.pageSize = pageSize;
if(this.pageSize<1)
this.pageSize=1;
else if(pageSize>20)
this.pageSize=20;

//        if(this.pageSize>totalRows){
//          this.pageSize=(int)totalRows;
//        }

totalPages =(int) Math.ceil((double)totalRows / (double)this.pageSize);
currentPage = 1;
startRow = 0;
}

/**
* 跳转到首页
*/
public void first()
{
this.currentPage = 1;
this.startRow = 0;
}

/**
* 跳转到上一页
*/
public void previous()
{
if (currentPage == 1)
{
return;
}
currentPage--;
startRow = (currentPage-1) * pageSize;
}

/**
* 跳转到下一页
*/
public void next()
{
if (currentPage < totalPages)
{
currentPage++;
}
startRow = (currentPage-1) * pageSize;
}

/**
*  跳转到尾页
*/
public void last()
{
this.currentPage = totalPages;
if(currentPage<1){
currentPage = 1;
}
this.startRow = (currentPage-1) * this.pageSize;
totalPages =(int) Math.ceil((double)totalRows / (double)this.pageSize);

}

/**
* 跳转到指定页
* @param currentPage   指定的页
*/
public void refresh(int currentPage)
{

if(currentPage < 0)
{
first();
}
if (currentPage > totalPages)
{
last();
}else{
this.currentPage = currentPage;
this.startRow = (currentPage-1) * this.pageSize;
}

}

public int getStartRow()
{
return startRow;
}

public int getTotalPages()
{
return totalPages;
}

public int getCurrentPage()
{
return currentPage;
}

public int getPageSize()
{
return pageSize;
}

public void setTotalRows(int totalRows)
{
this.totalRows = totalRows;
}

public void setStartRow(int startRow)
{
this.startRow = startRow;
}

public void setTotalPages(int totalPages)
{
this.totalPages = totalPages;
}

public void setCurrentPage(int currentPage)
{
this.currentPage = currentPage;
}

public void setPageSize(int pageSize)
{
this.pageSize = pageSize;
}

public int getTotalRows()
{
return totalRows;
}
}