1、 创建分页类

public class PageBean<T> {
	
	private int pageNum; 
	private int pageSize; 
	private int totalRecord;  
	private int totalPage;  
	private List<T> list;
	private int start;
	private int end;
	private int fromIndex;
	private int toIndex;
 
	public PageBean(int pageNum, int pageSize, int totalRecord) {
		this.pageNum = pageNum;
		this.pageSize = pageSize;
		this.totalRecord = totalRecord;
		fromIndex=(pageNum-1)*pageSize;
		toIndex=pageNum*pageSize>totalRecord?totalRecord:pageNum*pageSize;
 
		if (totalRecord % pageSize == 0) {
			this.totalPage = totalRecord / pageSize;
		} else {
			this.totalPage = totalRecord / pageSize + 1;
		}
		start = 1;
		end = 5;
		if (totalPage <= 5) {
			end = this.totalPage;
		} else {
			start = pageNum - 2;
			end = pageNum + 2;
 
			if (start < 1) {
				start = 1;
				end = 5;
			}
			if (end > this.totalPage) {
				end = totalPage;
				start = end - 5;
			}
		}
	}
 
	public int getPageNum() {
		return pageNum;
	}
 
	public void setPageNum(int pageNum) {
		this.pageNum = pageNum;
	}
 
	public int getPageSize() {
		return pageSize;
	}
 
	public void setPageSize(int pageSize) {
		this.pageSize = pageSize;
	}
 
	public int getTotalRecord() {
		return totalRecord;
	}
 
	public int getFromIndex() {
		return fromIndex;
	}
 
	public void setFromIndex(int fromIndex) {
		this.fromIndex = fromIndex;
	}
 
	public int getToIndex() {
		return toIndex;
	}
 
	public void setToIndex(int toIndex) {
		this.toIndex = toIndex;
	}
 
	public void setTotalRecord(int totalRecord) {
		this.totalRecord = totalRecord;
	}
 
	public int getTotalPage() {
		return totalPage;
	}
 
	public void setTotalPage(int totalPage) {
		this.totalPage = totalPage;
	}
 
	public List<T> getList() {
		return list;
	}
 
	public void setList(List<T> list) {
		this.list = list.subList(fromIndex, toIndex);
	}
 
	public int getStart() {
		return start;
	}
 
	public void setStart(int start) {
		this.start = start;
	}
 
	public int getEnd() {
		return end;
	}
 
	public void setEnd(int end) {
		this.end = end;
	}
 
}

2、 service层

@WebServlet("/main")
public class Servlets extends HttpServlet {
 
	@Override
	protected void service(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		String page = request.getParameter("pageNum");
		int pageNum = Integer.parseInt((page == null ? "1" : page));
		int pageSize = 5;
		Service s = new Service();
		PageBean<User> pb = s.findAll(pageNum, pageSize);
		request.setAttribute("pageBean", pb);
		request.getRequestDispatcher("/main.jsp").forward(request, response);
	}
}

3、 dao层

public class Service {
	public PageBean<User> findAll(int pageNum, int pageSize) {
		UserDao userDao = new UserDao();
		List<User> users = userDao.findAll();
		int totalRecord = users.size();
		PageBean<User> pb = new PageBean<>(pageNum, pageSize, totalRecord);
		pb.setList(users);
		return pb;
	}
}