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;
}
}