Paging feature in my project
1, ideas
Use a page control class, which record page information, such as page, next page, current page, etc. In the action of the query, this control class and query conditions are passed to the database access bean and then save the two parameters in the user session. In paging control Action, the BEAN access to the database is called using the received paging parameters.
2, realize
(1) Pieces Control class
/ * @Author Nick
* CREATED ON 2004-3-18
* File Name: PageController.java
*
*
* /
Package com.tower.util;
/ **
* @Author Nick
* 2004-3-18
* Used to turn page control
*
* /
Public class pageController {
INT TOTALROWSAMOUNT; / / total number
Boolean rowsamountset; // Whether to set TOTALROWSAMOUNT
INT PageSize = 2; // Variety per page
INT CurrentPage = 1; // Current page number
Int nextpage;
INT Previouspage;
INT TOTALPAGES; / / total page
Boolean Hasnext; // Is there a next page
Boolean Hasprevious; // Is there a previous page
String description;
INT PagestartRow;
Int pagendrow;
Public pageController (int Totalrow) {
SetTotAlrowsAmount (TotalRows);
}
Public pageController () {}
/ **
* @Param I
* Set the total number of lines
* /
Public void settotalrowsamount (int i) {
IF (! this.rowsamountset) {
Totalrowsamount = i;
Totalpages = Totalrowsamount / Pagesize 1;
SetCurrentPage (1);
THIS.ROWSAMOUNTSET = TRUE;
}
}
/ **
* @Param I
*
* current page
*
* /
Public void setCurrentPage (INT i) {
CurrentPage = i;
NextPage = CURRENTPAGE 1;
PreviousPage = CURRENTPAGE-1;
// Calculate the current page to start rows and end lines
CurrentPage * Pagesize PageEndrow = CURRENTPAGE * PAGESIZE PagestRow = PageEndrow-Pagesize 1; } else { PageEndrow = TotalRowsamount; PageStartrow = PageSize * (Totalpages-1) 1; } / / Is there a previous page and IF (NextPage> Totalpages) { Hasnext = FALSE; } else { Hasnext = True; } IF (previouspage == 0) { HaspRevious = false; } else { Hasprevious = true; } System.out.println (this.Description ()); } / ** * @Return * / Public int getcurrentpage () { Return CurrentPage; / ** * @Return * / Public boolean ishasnext () { Return hasnexT; } / ** * @Return * / Public boolean ishasis () { Return Hasprevious; } / ** * @Return * / Public int getNextPage () { Return nextpage; } / ** * @Return * / Public int getpagesize () { Return PageSize; } / ** * @Return * / Public int getPreviouspage () { Return Previouspage; } / ** * @Return * / Public int gettotalpages () { Return Totalpages; } / ** * @Return * / Public int gettotalrowsamount () { Return TotalrowsAmount; } / ** * @Param B * / Public void sethasnext (boolean b) { Hasnext = B; } / ** * @Param B * / Public void setHasprevious (Boolean B) { HaspRevious = B; } / ** * @Param I * / Public void setnextPage (INT i) { NextPage = i; } / ** * @Param I * / Public void setpageSize (int i) { PageSize = i; } / ** * @Param I * / Public void setpreviouspage (int i) { Previouspage = i; } / ** * @Param I * / Public void setTotalpages (INT I) { Totalpages = i; } / ** * @Return * / Public int getpagendrow () { Return PageEndRow; } / ** * @Return * / Public int getpagestRow () { Return PagestartRow; } Public string getdescription () { String description = "Total:" this.gettotalrowsamount () "items" this.gettotalpages () "pages"; // this.currentpage "previous" this.hasprevious // "Next:" this.hasnext // "START ROW:" this.pagestRow // "End Row:" this.pageendrow; Return description; } Public string description () { String description = "Total:" this.gettotalrowsamount () "items" this.gettotalpages () "Pages, Current Page: THIS.CURRENTPAGE "previous" this.hasprevious Next: " this.hasnext "START ROW:" this.pagestRrow "End Row:" this.pageendrow; Return description; } Public static void main (string args []) { PageController PC = New PageController (3); System.out.println (pc.getdescription ()); // pc.setcurrentpage (2); // system.out.println (pc.description ()); // pc.setcurrentpage (3); // system.out.println (pc.description ()); } } (2) Query the code snippet of Action Public ActionForward Execute ActionMapping mapping, Actionform Form, HTTPSERVLETREQUEST REQUEST, Httpservletresponse response Throws exception { Base queryform = (base) form; IF (! queryform.getname (). Equals ("")) { PageController PC = New PageController (); Employeebase service = new EmployeeBase (); ArrayList Result = (arraylist) Service.Search (Queryform, PC); HttpSession session = request.getations (); Session.setttribute ("Queryform", queryform); Session.SetaTRibute ("PageController", Service.getPageController ()); Request.setattribute ("QueryResult", Result; Request.setttribute ("PageController", Service.getPageController ()); Return mapping.findforward ("haveresult"); } else { Return mapping.findforward ("noresult"); } } (3), page the code snippet Public ActionForward Execute ActionMapping mapping, Actionform Form, HTTPSERVLETREQUEST REQUEST, Httpservletresponse response Throws exception { // Read forward page parameters TurNPageForm TurNPageForm = (TurNPageForm) Form; / / Take query information from pageController and use the call interface processing result provided by Bean HttpSession session = request.getations (); PageController PC = (pageController) session.getattribute ("PageController"); Base Queryform = (Base) session.getattribute ("queryform"); Pc.SetCurrentPage (TurnPageform.getViewPage ()); Employeebase service = new EmployeeBase (); ArrayList Result = (arraylist) Service.Search (Queryform, PC); / / Write data to request according to parameters Request.RemoveAttribute ("queryResult"); Request.RemoveAttribute ("PageController"); Request.setattribute ("QueryResult", Result; Request.setttribute ("PageController", PC); // forward to the display page Return mapping.findforward ("haveresult"); } (4) Database Access to Pieces in Beans Public Collection Search (Base Base, PageController PC) Throws sqlexception { ArrayList Emps = new arraylist (); ResultSet RS = GetSearchResult (BASE); Rs.absolute (-1); Pc.SettotAlrowsamount (Rs.Getrow ()); SETPAGECONTROLLER (PC); IF (rs.getrow ()> 0) { rs.absolute (pc.getpagestartrow ()); Do { System.out.println ("in loop" qGetrow ()); Base b = new base (); B.setname (rs.getstring ("name"); B.setidcard (rs.getstring ("iDCard")); System.out.println ("from DB:" rs.getstring ("iDCard")); Emps.Add (b); IF (! rs.next ()) { Break; } } while (rs.getrow () <(pc.getpageendrow () 1)); } Return EMPS; } (5) Code pieces in JSP NEXT In this way, the functionality of the page can be expressed to the client in the way you like.
