我的struts分页算法的实现(2)

String currentPage = request.getParameter("currentPage");
HttpSession session = request.getSession(); 
EmployeeForm employeeForm = (EmployeeForm) form;
String queryString = null;
String queryCon = null;
String action = employeeForm.getAction();
List list = new ArrayList();
PageBean pb = null;
EmployeeDao employeeDao = new EmployeeDao();
if(action == null || action.equals("null")){
int totalRows = employeeDao.getTotalRows();

pb = new PageBean(totalRows);
session.removeAttribute("page");
queryString = employeeForm.getQueryString();
queryCon = employeeForm.getQueryCon();
session.setAttribute("queryString",queryString);
session.setAttribute("queryCon",queryCon);   
list = employeeDao.getAllEmployee(queryString, queryCon,
String.valueOf(pb.getPageStartRow()),
String.valueOf(pb.getPageRecorders()));

}else if(action.equals("nextPage")){
queryString = (String)session.getAttribute("queryString");
queryCon = (String)session.getAttribute("queryCon");      
employeeForm.setQueryString(queryString);
employeeForm.setQueryCon(queryCon);
pb = (PageBean)session.getAttribute("page");
pb.nextPage();
list = employeeDao.getAllEmployee(queryString, queryCon,
String.valueOf(pb.getPageStartRow()),
String.valueOf(pb.getPageRecorders()));
}else if(action.equals("previousPage")){
queryString = (String)session.getAttribute("queryString");
queryCon = (String)session.getAttribute("queryCon");
employeeForm.setQueryString(queryString);
employeeForm.setQueryCon(queryCon);
pb = (PageBean)session.getAttribute("page");   
pb.previousPage();
list = employeeDao.getAllEmployee(queryString, queryCon,
String.valueOf(pb.getPageStartRow()),
String.valueOf(pb.getPageRecorders()));
}

pb.description();
session.setAttribute("page",pb);        
request.setAttribute("admin", "admin");
request.setAttribute("employee", list);
return mapping.findForward("showlist");

/**
*查询总记录数
*/
public int getTotalRows() {
int totalRows = 0;
String sql = "select count(*) from employee";//假设是员工表
Database db = new Database();
ResultSet rs = db.executeQuery(sql);
try {
while (rs.next()) {
String id = (String) rs.getString(1);
totalRows = Integer.parseInt(id);
}
} catch (SQLException e) {
e.printStackTrace();
}
db.close();
return totalRows;
}

/*
*查询每一页需要查询的页码
*/
public List getAllEmployee(String queryString, String queryCon,
String startRow,String num) {
List list = new ArrayList();
String sql = null;
if (queryString == null || queryString.equals("")) {
sql = "select * from employee,dept " +
"where dept.Id = employee.deptId " +
"order by employee.id asc"+ " limit "+startRow+","+num;
} else {
sql = "select * from employee,dept " +
"where dept.Id = employee.deptId order by employee."
+ queryString + " " + queryCon + " limit "+startRow+","+num;
}
Employee employee = null;
Database db = new Database();
ResultSet rs = db.executeQuery(sql);
try {
while (rs.next()) {
String id = (String) rs.getString("employee.id");
String name = (String) rs.getString("employee.name");
String deptId = (String) rs.getString("employee.deptId");
String deptName = (String) rs.getString("dept.deptName");
employee = new Employee();
employee.setId(id);
employee.setName(name);
employee.setDeptId(deptId);
employee.setDeptName(deptName);
list.add(employee);
}
} catch (SQLException e) {
e.printStackTrace();
}
db.close();
return list;
}