用Spring的JdbcTemplate实现分页功能
最近使用了spring中的JdbcTemplate实现数据库的查询和插入操作，发现spring的JdbcTemplate 不象HibernateTemplate那么好，已经实现了分页功能。所以要自己实现，使用 getJdbcTemplate().queryForList(string sql)得到的结果集是所有的。
如果你的查询有10000条记录，或者更多，速度肯定慢了，当然你可以通过resultset中的游标控制查询的起始和结束。我这里用的是Oracle数据库，使用伪列ROWNUM来实现分页。我的分页代码如下：
package com.deity.ranking.util;import java.util.List;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.support.JdbcDaoSupport;
/** * 分页函数 *
* @author allenpan */public class Pagination extends JdbcDaoSupport{
public static final int NUMBERS_PER_PAGE = 10;
//一页显示的记录数
private int numPerPage;
//记录总数
private int totalRows;
//总页数
private int totalPages;
//当前页码
private int currentPage;
//起始行数
private int startIndex;
//结束行数
private int lastIndex;
//结果集存放List
private List resultList;
//JdbcTemplate jTemplate
private JdbcTemplate jTemplate;
/**
* 每页显示10条记录的构造函数,使用该函数必须先给Pagination设置currentPage，jTemplate初值
* @param sql oracle语句
*/
public Pagination(String sql){
if(jTemplate == null){
throw new IllegalArgumentException("com.deity.ranking.util.Pagination.jTemplate is null,please initial it first. ");
}else if(sql.equals("")){
throw new IllegalArgumentException("com.deity.ranking.util.Pagination.sql is empty,please initial it first. ");
}
new Pagination(sql,currentPage,NUMBERS_PER_PAGE,jTemplate);
}
/**分页构造函数
* @param sql 根据传入的sql语句得到一些基本分页信息
* @param currentPage 当前页
* @param numPerPage 每页记录数
* @param jTemplate JdbcTemplate实例
*/
public Pagination(String sql,int currentPage,int numPerPage,JdbcTemplate jTemplate){
if(jTemplate == null){
throw new IllegalArgumentException("com.deity.ranking.util.Pagination.jTemplate is null,please initial it first. ");
}else if(sql == null || sql.equals("")){
throw new IllegalArgumentException("com.deity.ranking.util.Pagination.sql is empty,please initial it first. ");
}
//设置每页显示记录数
setNumPerPage(numPerPage);
//设置要显示的页数
setCurrentPage(currentPage);
//计算总记录数
StringBuffer totalSQL = new StringBuffer(" SELECT count(*) FROM ( ");
totalSQL.append(sql);
totalSQL.append(" ) totalTable ");
//给JdbcTemplate赋值
setJdbcTemplate(jTemplate);
//总记录数
setTotalRows(getJdbcTemplate().queryForInt(totalSQL.toString()));
//计算总页数
setTotalPages();
//计算起始行数
setStartIndex();
//计算结束行数
setLastIndex();
System.out.println("lastIndex="+lastIndex);//////////////////
//构造oracle数据库的分页语句
StringBuffer paginationSQL = new StringBuffer(" SELECT * FROM ( ");
paginationSQL.append(" SELECT temp.* ,ROWNUM num FROM ( ");
paginationSQL.append(sql);
paginationSQL.append("
) temp where ROWNUM <= " + lastIndex);
paginationSQL.append(" ) WHERE
num > " + startIndex);
//装入结果集
setResultList(getJdbcTemplate().queryForList(paginationSQL.toString()));
}
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
}
public int getCurrentPage() {
return currentPage;
}
public void setCurrentPage(int currentPage) {
this.currentPage = currentPage;
}
public int getNumPerPage() {
return numPerPage;
}
public void setNumPerPage(int numPerPage) {
this.numPerPage = numPerPage;
}
public List getResultList() {
return resultList;
}
public void setResultList(List resultList) {
this.resultList = resultList;
}
public int getTotalPages() {
return totalPages;
}
//计算总页数
public void setTotalPages() {
if(totalRows % numPerPage == 0){
this.totalPages = totalRows / numPerPage;
}else{
this.totalPages
= (totalRows / numPerPage) + 1;
}
}
public int getTotalRows() {
return totalRows;
}
public void setTotalRows(int totalRows) {
this.totalRows = totalRows;
}
public int getStartIndex() {
return startIndex;
}
public void setStartIndex() {
this.startIndex = (currentPage - 1) * numPerPage;
}
public int getLastIndex() {
return lastIndex;
}
public JdbcTemplate getJTemplate() {
return jTemplate;
}
public void setJTemplate(JdbcTemplate template) {
jTemplate = template;
}
//计算结束时候的索引
public void setLastIndex() {
System.out.println("totalRows="+totalRows);///////////
System.out.println("numPerPage="+numPerPage);///////////
if( totalRows < numPerPage){
this.lastIndex = totalRows;
}else if((totalRows % numPerPage == 0) || (totalRows % numPerPage != 0 && currentPage < totalPages)){
this.lastIndex = currentPage * numPerPage;
}else if(totalRows % numPerPage != 0 && currentPage == totalPages){//最后一页
this.lastIndex = totalRows ;
}
}}在我的业务逻辑代码中：
/**
* find season ranking list from DC
* @param areaId 选手区域id
* @param rankDate 赛季
* @param category 类别
* @param characterName 角色名
* @return List
*/
public List findSeasonRankingList(Long areaId, int rankYear,int rankMonth,
Long categoryId,String characterName) {
//SQL语句
StringBuffer sql = new StringBuffer(" SELECT C.USERID userid,D.POSNAME posname,C.GAMEID gameid,C.AMOUNT amount,C.RANK rank FROM ");
//表
sql.append(" (SELECT B.USERID USERID,");
sql.append(" B.POSID POSID,");
sql.append(" A.DISTRICT_CODE DISTRICTCODE,");
sql.append(" A.GAMEID GAMEID,");
sql.append(" AMOUNT AMOUNT,");
sql.append(" RANK RANK ");
sql.append(" FROM TB_FS_RANK A ");
sql.append(" LEFT JOIN TB_CHARACTER_INFO B ");
sql.append(" ON A.DISTRICT_CODE = B.DISTRICT_CODE ");
sql.append(" AND A.GAMEID = B.GAMEID ");
//附加条件
if(areaId != null && areaId.intValue() != 0){
sql.append(" and A.DISTRICT_CODE = " + areaId.intValue());
}
if( rankYear > 1970 && rankMonth > 0){
//hql.append(" and sas.id.dt >= to_date('" + rankYear + "-" + rankMonth + "-01 00:00:00'," + "YYYY-MM-DD HH24:MI:SS");
//hql.append(" and sas.id.dt <= to_date('" + rankYear + "-" + rankMonth + "-" + TimeTool.findMaxDateInMonth(rankYear,rankMonth) + " 23:59:59'," + "YYYY-MM-DD HH24:MI:SS");
sql.append(" and A.DT = fn_time_convert(to_date('" + rankYear + "-" + rankMonth + "'," + "'YYYY-MM')) ");
}
if(categoryId != null && categoryId.intValue() != 0){
sql.append(" and A.CID = " + categoryId.intValue());
}
if(characterName != null && !characterName.trim().equals("")){
sql.append(" and A.GAMEID = '" + characterName.trim()+"' ");
}
sql.append(" ORDER BY RANK ASC) C ");
sql.append(" LEFT JOIN TB_FS_POSITION D ");
sql.append(" ON C.POSID = D.POSID ");
sql.append(" ORDER BY C.RANK ");
System.out.println("hql="+sql.toString());////////////////
//使用自己的分页程序控制结果集
Pagination pageInfo = new Pagination(sql.toString(),1,10,getJdbcTemplate());
return pageInfo.getResultList();
//return getJdbcTemplate().queryForList(sql.toString());
}