用Spring的JdbcTemplate实现分页功能

1/5/2008来源:Java教程人气:26262


  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。
  
  假如你的查询有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());
  }