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
                       
                      
                     
                    
                   
                  
                 
                
               
              
             
            
           
          
         
        
       
      

 

BookService

1 /* 2  * 图书模块业务层 3  */ 4 public class BookService { 5     private BookDao bookDao = new BookDao(); 6  7     public PageBean
      
        findByCategory(String cid, int pc) { 8  9         try {10             return bookDao.findByCategory(cid, pc);11         } catch (SQLException e) {12             throw new RuntimeException(e);13         }14 15     }16 17     // 按书名查询18 19     public PageBean
       
         findByBname(String bname, int pc) {20 21         try {22             return bookDao.findByBname(bname, pc);23         } catch (SQLException e) {24             throw new RuntimeException(e);25         }26 27     }28 29     // 按作者查询30     public PageBean
        
          findByAuthor(String author, int pc) {31 32         try {33             return bookDao.findByAuthor(author, pc);34         } catch (SQLException e) {35             throw new RuntimeException(e);36         }37 38     }39 40     // 按出版社查询41     public PageBean
         
           findByPress(String press, int pc) {42 43         try {44             return bookDao.findByAuthor(press, pc);45         } catch (SQLException e) {46             throw new RuntimeException(e);47         }48 49     }50    51     //多条件组合查询52     public PageBean
          
            findByCombination(Book criteria, int pc)53             throws SQLException {54         try {55             return bookDao.findByCombination(criteria, pc);56         } catch (SQLException e) {57             throw new RuntimeException(e);58         }59 60     }61 62 }
          
         
        
       
      

BookServlet

1 //获取当前页码值 2     private int getPc(HttpServletRequest req) 3     { 4         int pc=1; 5         String param=req.getParameter("pc"); 6         if(param!=null&&!param.trim().isEmpty()) 7         {    8             try{ 9             pc=Integer.parseInt(param);10             }catch(RuntimeException e){}11         }12         return pc;13     }14 15     //获取url  截取url 页面中的分页导航中使用它作为超链接的目标  还带了条件 保证条件不丢16     private String getUrl(HttpServletRequest req)17     {    //http://localhost:8080//goods/BookServlet18         //getRequestURI()获取/goods/BookServlet19         //req.getQueryString()获取method=findByCategory&cid=xxx20         String url=req.getRequestURI()+"?"+req.getQueryString();21         //如果url中存在pc参数 截取掉 如果不存在则不用截取22         int index=url.lastIndexOf("&pc=");23         if(index!=-1)24         {25             url=url.substring(0,index);26         }27         return url;28     }29 30     public String findByCategory(HttpServletRequest req, HttpServletResponse resp)31             throws ServletException, IOException {32         33         //得到pc 如果页面传递使用页面的 如果没传pc=134         int pc=getPc(req);35         36         //2得到url37         String url=getUrl(req);38         //3获取查询条件 本方法是cid 即分类id39         String cid=req.getParameter("cid");40         41         //使用pc cid 调用service 42         PageBean
      
        pb=bookService.findByCategory(cid,pc);43         //使用pageBean设置url 保存pageBean 转发到/jsps/book/list.jsp页面44          pb.setUrl(url); 45          req.setAttribute("pb", pb);46          return "f:/jsps/book/list.jsp";47        48         49     }
      

 

left.jsp

1 
     
       2         
      
        3         
       
 4                 
        
          5                     
           7                     
         
 8                         ¥${book.currPrice}  9                         ¥${book.price}10                         (${book.discount}折)11                     
12                     
         
13                         ${book.bname }16                     
17                     
         
18                         ${book.author }20                     
21                     
         
22                         出 版 社：${book.press} }23                     
24                     
         
25                         出版时间：${book.publishtime}26                     
27                 
        
28         
      29 30 31