分页页码计算算法

最近做网站用到了分页页码计算的算法，觉得之前一直用的不好,自己写了一个，拿出来与大家共享一下:

package cnblogs.xiaoqiu.test;

/**
 * 1.如果是5个可见页码,1-12345,2-12345,3-12345,4-23456,5-34567,6-45678,7-56789
 * 8-678910,9-678910,10-678910
 * @author CHICHAO
 * @date 2012-5-10
 */
public class WebTool {
    public static PageIndex getPageIndex(int viewedIndex,int currentPage,int totalPage){
        int firstIndex = (currentPage<=viewedIndex/2+1?1:(currentPage-viewedIndex/2));
        int lastIndex = (firstIndex+viewedIndex-1>=totalPage?totalPage:firstIndex+viewedIndex-1);
        if(lastIndex>=totalPage)
            firstIndex = lastIndex - viewedIndex+1;
        PageIndex pageIndex = new PageIndex(firstIndex,lastIndex);
        return pageIndex;
    }
    public static void main(String[] args){
        System.out.println(getPageIndex(10, 119, 120).getFirstIndex()+"-"+getPageIndex(10,119,120).getLastIndex());
    }
}

class PageIndex{
    private int firstIndex;
    private int lastIndex;
    
    public PageIndex(int firstIndex, int lastIndex) {
        this.firstIndex = firstIndex;
        this.lastIndex = lastIndex;
    }
    public int getFirstIndex() {
        return firstIndex;
    }
    public void setFirstIndex(int firstIndex) {
        this.firstIndex = firstIndex;
    }
    public int getLastIndex() {
        return lastIndex;
    }
    public void setLastIndex(int lastIndex) {
        this.lastIndex = lastIndex;
    }
}