分页模型

public class Pager {
	private int totalRows;
	private int pageSize = 5;
	private int currentPage;
	private int totalPages;
	private int startRow;
	
	public Pager(){}
	
	public Pager(int _totalRows) {
		totalRows = _totalRows;
		totalPages = totalRows / pageSize;
		int mod = totalRows % pageSize;
		if(mod > 0){
			totalPages++;
		}
		currentPage = 1;
		startRow = 0;
	}

	public int getTotalRows() {
		return totalRows;
	}

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

	public int getPageSize() {
		return pageSize;
	}

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

	public int getCurrentPage() {
		return currentPage;
	}

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

	public int getTotalPages() {
		return totalPages;
	}

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

	public int getStartRow() {
		return startRow;
	}

	public void setStartRow(int startRow) {
		this.startRow = startRow;
	}
	
	public void first() {
		currentPage = 1;
		startRow = 0;
	}
	
	public void previous() {
		if (currentPage == 1){
			return;
		}
		currentPage--;
		startRow = (currentPage - 1) * pageSize;
	}
	
	public void next() {
		if (currentPage < totalPages){
			currentPage++;
		}
		startRow = (currentPage - 1) * pageSize;
	}
	
	public void last() {
		currentPage = totalPages;
		startRow = (currentPage -1 ) * pageSize;
	}
	
	public void refresh (int _currentPage) {
		currentPage = _currentPage;
		if (currentPage > totalPages){
			last();
		}
	}
}