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// 计ç®æ»çè®°å½æ¡æ°
String SQL = "SELECT Count(*) AS total " + this.QueryPart;
rs = db.executeQuery(SQL);
if (rs.next())
Total = rs.getInt(1);
// 设置å½å页æ°åæ»é¡µæ°
TPages = (int)Math.ceil((double)this.Total/this.MaxLine);
CPages = (int)Math.floor((double)Offset/this.MaxLine+1);
// æ ¹æ®æ¡ä»¶å¤æï¼ååºæéè®°å½
if (Total > 0) {
SQL = Query + " LIMIT " + Offset + " , " + MaxLine;
rs = db.executeQuery(SQL);
}
return rs;
}
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<%
sqlStmt = sqlCon.createStatement(java.sql.ResultSet.TYPE_SCROLL_INSENSITIVE,
java.sql.ResultSet.CONCUR_READ_ONLY);
strSQL = "select name,age from test";
//æ§è¡SQLè¯å¥å¹¶è·åç»æé
sqlRst = sqlStmt.executeQuery(strSQL);
//è·åè®°å½æ»æ°
sqlRst.last();
intRowCount = sqlRst.getRow();
//è®°ç®æ»é¡µæ°
intPageCount = (intRowCount+intPageSize-1) / intPageSize;
//è°æ´å¾
æ¾ç¤ºç页ç
if(intPage>intPageCount) intPage = intPageCount;
%>
<table border="1" cellspacing="0" cellpadding="0">
<tr>
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</tr>
<%
if(intPageCount>0){
//å°è®°å½æéå®ä½å°å¾
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sqlRst.absolute((intPage-1) * intPageSize + 1);
//æ¾ç¤ºæ°æ®
i = 0;
while(i<intPageSize && !sqlRst.isAfterLast()){
%>
<tr>
<td><%=sqlRst.getString(1)%></td>
<td><%=sqlRst.getString(2)%></td>
</tr>
<%
sqlRst.next();
i++;
}
}
%>
</table>
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public interface Pageable extends java.sql.ResultSet{
/**è¿åæ»é¡µæ°
*/
int getPageCount();
/**è¿åå½å页çè®°å½æ¡æ°
*/
int getPageRowsCount();
/**è¿åå页大å°
*/
int getPageSize();
/**转å°æå®é¡µ
*/
void gotoPage(int page) ;
/**设置å页大å°
*/
void setPageSize(int pageSize);
/**è¿åæ»è®°å½è¡æ°
*/
int getRowsCount();
/**
* 转å°å½å页ç第ä¸æ¡è®°å½
* @exception java.sql.SQLException å¼å¸¸è¯´æã
*/
void pageFirst() throws java.sql.SQLException;
/**
* 转å°å½å页çæåä¸æ¡è®°å½
* @exception java.sql.SQLException å¼å¸¸è¯´æã
*/
void pageLast() throws java.sql.SQLException;
/**è¿åå½å页å·
*/
int getCurPage();
}
è¿æ¯ä¸ä¸ªå¯¹java.sql.ResultSetè¿è¡äºæ©å±çæ¥å£ï¼ä¸»è¦æ¯å¢å äºå¯¹å页çæ¯æï¼å¦è®¾ç½®å页大å°ï¼è·³è½¬å°æä¸é¡µï¼è¿åæ»é¡µæ°ççã
æ¥çï¼æ们éè¦å®ç°è¿ä¸ªæ¥å£ï¼ç±äºè¿ä¸ªæ¥å£ç»§æ¿èªResultSetï¼å¹¶ä¸å®ç大é¨ååè½ä¹é½åResultSetåæåè½ç¸åï¼æ以è¿é使ç¨äºä¸ä¸ªç®åçDecorator模å¼ã
PageableResultSet2ç类声æåæå声æå¦ä¸ï¼
public class PageableResultSet2 implements Pageable {
protected java.sql.ResultSet rs=null;
protected int rowsCount;
protected int pageSize;
protected int curPage;
protected String command = "";
}
å¯ä»¥çå°ï¼å¨PageableResultSet2ä¸ï¼å
å«äºä¸ä¸ªResultSetçå®ä¾ï¼è¿ä¸ªå®ä¾åªæ¯å®ç°äºResultSetæ¥å£ï¼äºå®ä¸å®æ¯ç±å个æ°æ®åºåååå«å®ç°çï¼ï¼å¹¶ä¸æææç±ResultSet继æ¿æ¥çæ¹æ³é½ç´æ¥è½¬åç»è¯¥å®ä¾æ¥å¤çã
PageableResultSet2ä¸ç»§æ¿èªResultSetç主è¦æ¹æ³ï¼
//â¦â¦
public boolean next() throws SQLException {
return rs.next();
}
//â¦â¦
public String getString(String columnName) throws SQLException {
try {
return rs.getString(columnName);
}
catch (SQLException e) {//è¿éæ¯ä¸ºäºå¢å ä¸äºåºéä¿¡æ¯çå
容便äºè°è¯
throw new SQLException (e.toString()+" columnName="
+columnName+" SQL="+this.getCommand());
}
}
//â¦â¦
åªæå¨Pageableæ¥å£ä¸æ°å¢çæ¹æ³æéè¦èªå·±çåæ¹æ³å¤çã
/**æ¹æ³æ³¨éå¯åèPageable.java
*/
public int getCurPage() {
return curPage;
}
public int getPageCount() {
if(rowsCount==0) return 0;
if(pageSize==0) return 1;
//calculate PageCount
double tmpD=(double)rowsCount/pageSize;
int tmpI=(int)tmpD;
if(tmpD>tmpI) tmpI++;
return tmpI;
}
public int getPageRowsCount() {
if(pageSize==0) return rowsCount;
if(getRowsCount()==0) return 0;
if(curPage!=getPageCount()) return pageSize;
return rowsCount-(getPageCount()-1)*pageSize;
}
public int getPageSize() {
return pageSize;
}
public int getRowsCount() {
return rowsCount;
}
public void gotoPage(int page) {
if (rs == null)
return;
if (page < 1)
page = 1;
if (page > getPageCount())
page = getPageCount();
int row = (page - 1) * pageSize + 1;
try {
rs.absolute(row);
curPage = page;
}
catch (java.sql.SQLException e) {
}
}
public void pageFirst() throws java.sql.SQLException {
int row=(curPage-1)*pageSize+1;
rs.absolute(row);
}
public void pageLast() throws java.sql.SQLException {
int row=(curPage-1)*pageSize+getPageRowsCount();
rs.absolute(row);
}
public void setPageSize(int pageSize) {
if(pageSize>=0){
this.pageSize=pageSize;
curPage=1;
}
}
PageableResultSet2çæé æ¹æ³ï¼
public PageableResultSet2(java.sql.ResultSet rs) throws java.sql.SQLException {
if(rs==null) throw new SQLException("given ResultSet is NULL","user");
rs.last();
rowsCount=rs.getRow();
rs.beforeFirst();
this.rs=rs;
}
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¶æ¯å¨ä¸éè¦å页åè½çæ¶åï¼å¯ä»¥ç´æ¥å½æResultSet使ç¨ãèå¨éè¦å页æ¶ï¼åªéè¦ç®åçsetPageSize, gotoPageï¼å³å¯ã
PreparedStatement pstmt=null;
Pageable rs=null;
â¦â¦//æé SQLï¼å¹¶åå¤ä¸ä¸ªpstmt.
rs=new PageableResultSet2(pstmt.executeQuery());//æé ä¸ä¸ªPageable
rs.setPageSize(20);//æ¯é¡µ20个记å½
rs.gotoPage(2);//跳转å°ç¬¬2页
for(int i=0; i<rs.getPageRowsCount(); i++){//循ç¯å¤ç
int id=rs.getInt(âIDâ);
â¦â¦//继ç»å¤ç
}
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