Implement pagination in struts

 

I can see it online and learn it.

1. iformpages interface. Each form that requires paging inherits this interface:
Package com. Fellow. Pub. servlet;

Public interface iformpages {
Int getcurrentpage ();
Void setcurrentpage (INT currentpage );
Int getitemperpage ();
Void setitemperpage (INT itemperpage );
}

2. pagination computing pages:
Package com. Fellow. Pub. util;

Import java. util. vector;
Import java. util. collection;
Import com. Fellow. Pub. servlet. iformpages;

Public class pages {
Protected int itemcount;
Protected int itemperpage;
Protected int currentpage;

Public pages (){
This. itemcount = 0;
This. itemperpage = 0;
This. currentpage = 1;
}

Public pages (INT itemcount, int itemperpage) throws exception {
This (itemcount, itemperpage, 1 );
}

Public pages (INT itemcount, int itemperpage, int currentpage) throws exception {
This. itemcount = (itemcount <= 0 )? 0: itemcount;
This. itemperpage = (itemperpage <= 0 )? 20: itemperpage;
Int curpage = (currentpage <= 0 )? 1: currentpage;

Int pagecount = (itemcount % itemperpage = 0 )? (Itemcount/itemperpage) :( itemcount/itemperpage + 1 );
If (curpage> pagecount) curpage = pagecount;
This. currentpage = curpage;
}

Public pages (Collection collection, iformpages formpages) throws exception {
This (collection. Size (), formpages. getitemperpage (), formpages. getcurrentpage ());
}

Public int getitemcount (){
Return this. itemcount;
}

Public void setitemcount (INT itemcount ){
This. itemcount = itemcount;
}

Public int getitemperpage (){
Return this. itemperpage;
}

Public void setitemperpage (INT itemperpage ){
This. itemperpage = itemperpage;
}

Public int getcurrentpage (){
Return this. currentpage;
}

Public void setcurrentpage (INT currentpage ){
This. currentpage = currentpage;
}

Public int getprepage (){
Return this. currentpage-1;
}

Public int getnextpage (){
Return this. currentpage + 1;
}

Protected void asserterrors () throws exception {
If (itemperpage <= 0 |
Currentpage <= 0 |
Itemcount <itemperpage * (currentpage-1 )){
Throw new exception ("pages object calculated error ");
}
}

Public int getpagecount () throws exception {
If (itemcount <= 0) return 0;
Asserterrors ();
If (itemcount % itemperpage = 0 ){
Return itemcount/itemperpage;
}
Else {
Return itemcount/itemperpage + 1;
}
}

Public int getpageitemcount () throws exception {
If (itemcount <= 0) return 0;
Int pagecount = getpagecount ();

If (pagecount = currentpage ){
Return itemcount-itemperpage * (currentpage-1 );
}
Else {
Return itemperpage;
}
}

Public int getpageitemcount (INT currentpage) throws exception {
If (itemcount <= 0) return 0;
Int pagecount = getpagecount ();

If (pagecount = currentpage ){
Return itemcount-itemperpage * (currentpage-1 );
}
Else {
Return itemperpage;
}
}

Public Boolean isfirstpage () throws exception {
Return (currentpage = 1 );
}

Public Boolean islastpage () throws exception {
Int pagecount = getpagecount ();
Return (pagecount = currentpage );
}

Public Collection getindexlist () throws exception {
Int pagecount = getpagecount ();
Vector result = new vector (pagecount );
For (INT I = 0; I <pagecount; I ++ ){
Result. Add (New INTEGER (I + 1 ));
}
Return result;
}
}

3. the pagination collection class collectionpages inherits pages:
Package com. Fellow. Pub. util;

Import java. util .*;

Import com. Fellow. Pub. servlet. iformpages;

Public class collectionpages extends pages {
Protected collection = NULL;
Protected collection collectionpage = NULL;
Public collectionpages (Collection collection,
Iformpages formpages) throws exception {
Super (collection, formpages );
This. Collection = collection;
Buildcollectionpage ();
}

Public Collection getcollection (){
Return this. collection;
}

Public void setcollection (Collection collection ){
This. Collection = collection;
}

Public Collection getcollectionpage (){
Return this. collectionpage;
}

Public Collection buildcollectionpage () throws exception {
If (Collection = NULL ){
Throw new exception ("collection object is null ");
}

Collectionpage = new vector (itemperpage );
Collectionutil. Copy (collection, collectionpage,
(Currentpage-1) * itemperpage,
(Currentpage) * itemperpage );
Return collectionpage;
}
}

4. Initialization in the action:
Collectionpages = new collectionpages (collection, formpages );
Collection is the set to be paged.

5. Save to request
Setattribute (name, collectionpages );

6. Use the collectionpages object on the page. The collectionpages object has two sub-objects:
I. collectionpage is the set after pagination.
<Bean: Define id = "collectionlist" name = "collectionpages" property = "collectionpage" Scope = "request"/>
Ii. indexlist is the page number (because I don't know how to process the page number in a simple way, I have to get such an object to iterate)
<Bean: Define id = "indexlist" name = "collectionpages" property = "indexlist" Scope = "request"/>