JPA entityManager 实现 分页查询

@Overridepublic PageModel queryForPager(int pageNumber, int pageSize,Class entityClass, String condition, String sort,HttpServletRequest request, Object... params) {EntityManager entityManager = getEntityManager(request,1);String schemaName = entityManager.getProperties().get("id")+"";PageModel page = new PageModel();String sqllist = SqlHelper.generateSelectSqlForPager(pageNumber,pageSize, entityClass, condition, sort,schemaName);String sqlcount = SqlHelper.generateSelectSqlForCount(entityClass,condition);if(params instanceof Object[]){sqllist = formatSql(sqllist,params);sqlcount = formatSql(sqlcount,params);}Query createNativeQuery = entityManager.createNativeQuery(SqlParserUtil.sqlParserForSelect(sqllist, schemaName));List resultList = createNativeQuery.getResultList();Query createNativeQuery2 = entityManager.createNativeQuery(SqlParserUtil.sqlParserForSelect(sqlcount, schemaName));List resultList2 = createNativeQuery2.getResultList();page.setList(resultList);page.setTotalRows(resultList2.size());page.setPageSize(pageSize);page.setPageNumber(pageNumber);page.setTotalPages((int) Math.ceil((double) page.getTotalRows()/ (double) pageSize));return page;}/* * 参数转换 */private String formatSql(String sql, Object[] params) {Object[] arr = params;int i  =0;while(sql.contains("?")){sql = sql.replaceFirst("\\?", "'"+arr[i]+"'");;i++;}if(i!=arr.length){throw new RuntimeException("参数与替换参数 数目不相等");}return sql;}@Overridepublic PageModel queryForPagerSQL(int pageNumber, int pageSize,Class entityClass, String condition, String sort, String sql,String sql1, HttpServletRequest request,Object... params) {EntityManager entityManager = getEntityManager(request,1);String schemaName = entityManager.getProperties().get("id")+"";PageModel page = new PageModel();String sqllist = sql + " where " + condition + " order by " + sort +" limit " + ((pageNumber - 1) * pageSize) + "," + pageSize;sqllist = SqlParserUtil.sqlParserForSelect(sqllist, schemaName);sqllist = "select (@i:=@i+1)AS i,t.* from ("+sqllist+") as t,(SELECT   @i:=0) AS it";String sqlcount = sql1 + " where " + condition;if(params instanceof Object[]){sqllist = formatSql(sqllist,params);sqlcount = formatSql(sqlcount, params);}Query createNativeQuery = entityManager.createNativeQuery(sqllist);List resultList = createNativeQuery.getResultList();Query createNativeQuery2 = entityManager.createNativeQuery(SqlParserUtil.sqlParserForSelect(sqlcount, schemaName));List resultList2 = createNativeQuery2.getResultList();page.setList(resultList);page.setTotalRows(resultList2.size());page.setPageSize(pageSize);page.setPageNumber(pageNumber);page.setTotalPages((int) Math.ceil((double) page.getTotalRows()/ (double) pageSize));return page;}@Overridepublic PageModel queryForPagerSQLGroup(int pageNumber, int pageSize,Class entityClass, String condition, String sort, String sql,String sql1, HttpServletRequest request, Object... params) {EntityManager entityManager = getEntityManager(request,1);String schemaName = entityManager.getProperties().get("id")+"";PageModel page = new PageModel();String sqllist = sql + " where " + condition + " order by " + sort +" limit " + ((pageNumber - 1) * pageSize) + "," + pageSize;sqllist = SqlParserUtil.sqlParserForSelect(sqllist, schemaName);int a=((pageNumber - 1) * pageSize);sqllist = "select (@i:=@i+1)AS i,t.* from ("+sqllist+") as t,(SELECT   @i:="+a+") AS it";String sqlcount = sql1 + " where " + condition;sqlcount="Select Count(*) from ("+sqlcount+") t ";if(params instanceof Object[]){sqllist = formatSql(sqllist,params);sqlcount = formatSql(sqlcount, params);}Query createNativeQuery = entityManager.createNativeQuery(sqllist);List resultList = createNativeQuery.getResultList();Query createNativeQuery2 = entityManager.createNativeQuery(SqlParserUtil.sqlParserForSelect(sqlcount, schemaName));List resultList2 = createNativeQuery2.getResultList();page.setList(resultList);page.setTotalRows(resultList2.size());page.setPageSize(pageSize);page.setPageNumber(pageNumber);page.setTotalPages((int) Math.ceil((double) page.getTotalRows()/ (double) pageSize));return page;}