java分页

package paper;

import java.util.List;

public class PageModel {
	
	private int page = 1; // 当前页

	public int totalPages = 0; // 总页数

	private int pageRecorders = 5;// 每页5条数据

	private int totalRows = 0; // 总数据数

	private int pageStartRow = 0;// 每页的起始数

	private int pageEndRow = 0; // 每页显示数据的终止数

	private boolean hasNextPage = false; // 是否有下一页

	private boolean hasPreviousPage = false; // 是否有前一页

	@SuppressWarnings("unchecked")
	private List list;

	// private Iterator it;

	@SuppressWarnings("unchecked")
	public PageModel(List list, int pageRecorders) {
		init(list, pageRecorders);// 通过对象集，记录总数划分
	}

	/** */
	/**
	 * 初始化list，并告之该list每页的记录数
	 * 
	 * @param list
	 * @param pageRecorders
	 */
	@SuppressWarnings("unchecked")
	public void init(List list, int pageRecorders) {
		this.pageRecorders = pageRecorders;
		this.list = list;
		totalRows = list.size();
		// it = list.iterator();
		hasPreviousPage = false;
		if ((totalRows % pageRecorders) == 0) {
			totalPages = totalRows / pageRecorders;
		} else {
			totalPages = totalRows / pageRecorders + 1;
		}

		if (page >= totalPages) {
			hasNextPage = false;
		} else {
			hasNextPage = true;
		}

		if (totalRows < pageRecorders) {
			this.pageStartRow = 0;
			this.pageEndRow = totalRows;
		} else {
			this.pageStartRow = 0;
			this.pageEndRow = pageRecorders;
		}
	}

	// 判断要不要分页
	public boolean isNext() {
		return list.size() > 5;
	}

	public void setHasPreviousPage(boolean hasPreviousPage) {
		this.hasPreviousPage = hasPreviousPage;
	}

	public String toString(int temp) {
		String str = Integer.toString(temp);
		return str;
	}

	public void description() {

		String description = "共有数据数:" + this.getTotalRows() +

		"共有页数: " + this.getTotalPages() +

		"当前页数为:" + this.getPage() +

		" 是否有前一页: " + this.isHasPreviousPage() +

		" 是否有下一页:" + this.isHasNextPage() +

		" 开始行数:" + this.getPageStartRow() +

		" 终止行数:" + this.getPageEndRow();

		System.out.println(description);
	}

	@SuppressWarnings("unchecked")
	public List getNextPage() {
		page = page + 1;

		disposePage();

		System.out.println("用户凋用的是第" + page + "页");
		this.description();
		return getObjects(page);
	}

	/** */
	/**
	 * 处理分页
	 */
	private void disposePage() {

		if (page == 0) {
			page = 1;
		}

		if ((page - 1) > 0) {
			hasPreviousPage = true;
		} else {
			hasPreviousPage = false;
		}

		if (page >= totalPages) {
			hasNextPage = false;
		} else {
			hasNextPage = true;
		}
	}

	@SuppressWarnings("unchecked")
	public List getPreviousPage() {

		page = page - 1;

		if ((page - 1) > 0) {
			hasPreviousPage = true;
		} else {
			hasPreviousPage = false;
		}
		if (page >= totalPages) {
			hasNextPage = false;
		} else {
			hasNextPage = true;
		}
		this.description();
		return getObjects(page);
	}

	/** */
	/**
	 * 获取第几页的内容
	 * 
	 * @param page
	 * @return
	 */
	@SuppressWarnings("unchecked")
	public List getObjects(int page) {
		if (page == 0 || page < 0) {
			page = 1;
		} else {
			this.setPage(page);
		}
		this.disposePage();
		if (page * pageRecorders < totalRows) {// 判断是否为最后一页
			pageEndRow = page * pageRecorders;
			pageStartRow = pageEndRow - pageRecorders;
		} else {
			pageEndRow = totalRows;
			pageStartRow = pageRecorders * (totalPages - 1);
		}

		List objects = null;
		if (!list.isEmpty()) {
			objects = list.subList(pageStartRow, pageEndRow);
		}
		// this.description();
		return objects;
	}

	@SuppressWarnings("unchecked")
	public List getFistPage() {
		if (this.isNext()) {
			return list.subList(0, pageRecorders);
		} else {
			return list;
		}
	}

	public boolean isHasNextPage() {
		return hasNextPage;
	}

	public void setHasNextPage(boolean hasNextPage) {
		this.hasNextPage = hasNextPage;
	}

	@SuppressWarnings("unchecked")
	public List getList() {
		return list;
	}

	@SuppressWarnings("unchecked")
	public void setList(List list) {
		this.list = list;
	}

	public int getPage() {
		return page;
	}

	public void setPage(int page) {
		this.page = page;
	}

	public int getPageEndRow() {
		return pageEndRow;
	}

	public void setPageEndRow(int pageEndRow) {
		this.pageEndRow = pageEndRow;
	}

	public int getPageRecorders() {
		return pageRecorders;
	}

	public void setPageRecorders(int pageRecorders) {
		this.pageRecorders = pageRecorders;
	}

	public int getPageStartRow() {
		return pageStartRow;
	}

	public void setPageStartRow(int pageStartRow) {
		this.pageStartRow = pageStartRow;
	}

	public int getTotalPages() {
		return totalPages;
	}

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

	public int getTotalRows() {
		return totalRows;
	}

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

	public boolean isHasPreviousPage() {
		return hasPreviousPage;
	}

}

 

 

package paper;

import java.util.ArrayList;
import java.util.List;

public class TestPagerModel {
	@SuppressWarnings("unchecked")
	public static void main(String args[]) {
		List<String> list = new ArrayList<String>();
		list.add("a");
		list.add("b");
		list.add("c");
		list.add("d");
		list.add("e");
		list.add("f");
		list.add("g");
		list.add("h");
		list.add("i");
		list.add("j");
		list.add("k");
		list.add("l");
		list.add("m");
		list.add("n");
		list.add("o");
		list.add("p");
		list.add("q");
		list.add("r");
		list.add("s");
		list.add("t");
		list.add("u");
		list.add("v");
		list.add("w");
		list.add("x");
		list.add("y");
		list.add("z");

		PageModel pm = new PageModel(list, 5);

		List sublist = pm.getObjects(2);
		for (int i = 0; i < sublist.size(); i++) {
			System.out.println(sublist.get(i));
		}
		
		System.out.println("当前页" + pm.getPage());
		System.out.println("总页数" + pm.getTotalPages());
		System.out.println("每页5条数据" + pm.getPageRecorders());
		System.out.println("总数据数" + pm.getTotalRows());
		System.out.println("每页的起始数" + pm.getPageStartRow());
		System.out.println("每页显示数据的终止数" + pm.getPageEndRow());
	}

}