Goods:图书模块按分类查询各层实现

BookDao

  1  //按分类查询
  2       public PageBean  findByCategory(String cid,int pc) throws SQLException
  3       {
  4           List exprList=new ArrayList();
  5           exprList.add(new Expression("cid", "=", cid));
  6           return findByCriteria(exprList, pc);
  7           
  8       }
  9       
 10       //按书名做一个模糊查询
 11       public PageBean  findByBname(String bname,int pc) throws SQLException
 12       {
 13           List exprList=new ArrayList();
 14           exprList.add(new Expression("bname", "like", "%"+bname+"%"));
 15           return findByCriteria(exprList, pc);
 16           
 17       }
 18       
 19       //按作者查询
 20       public PageBean  findByAuthor(String author,int pc) throws SQLException
 21       {
 22           List exprList=new ArrayList();
 23           exprList.add(new Expression("author", "like", "%"+author+"%"));
 24           return findByCriteria(exprList, pc);
 25           
 26       }
 27       
 28       
 29       //按出版社查询
 30       public PageBean  findByPress(String press,int pc) throws SQLException
 31       {
 32           List exprList=new ArrayList();
 33           exprList.add(new Expression("press", "like", "%"+press+"%"));
 34           return findByCriteria(exprList, pc);
 35           
 36       }
 37       //多条件组合查询  book对象本身就是条件
 38       public PageBean  findByCombination(Book criteria,int pc) throws SQLException
 39       {
 40           List exprList=new ArrayList();
 41           exprList.add(new Expression("bname", "like", "%"+criteria.getBname()+"%"));
 42           exprList.add(new Expression("author", "like", "%"+criteria.getAuthor()+"%"));
 43           exprList.add(new Expression("press", "like", "%"+criteria.getPress()+"%"));
 44           return findByCriteria(exprList, pc);
 45           
 46       }
 47       
 48       //
 49       
 50       /*
 51        * 通用的查询方法
 52        */
 53       private PageBean findByCriteria(List exprList,int pc) throws SQLException
 54       {  
 55           /*
 56            * 1、得到ps
 57            * 2\得到tr 总记录数 通过 通过exprList生成where子句
 58            * 3\得到beanlist
 59            * 4\创建PageBean 返回
 60            */
 61           //得到ps
 62           int ps=PageConstants.BOOK_PAGE_SIZE;
 63           /*
 64            *总记录数 通过exprList生成where子句  select * from t_book where 1=1 and ..
 65            *条件语句不好控制所以为了后面统一  在前面先给个1=1 后面统一用and 开头 拼凑sql语句的一重要技巧
 66            */
 67           StringBuilder whereSql=new StringBuilder("where 1=1");
 68           List