分析PetShop

分析PetShop

 

 

以前就把petShop这个实例DOWN下来了,这是微软主要针对SUN公司的petStore而发布的一款源代码,好了,不多说.现在来看看此源码的主要内容.
它由多个项目组合而成,大致分为以下几层:
BLL。专门处理前台页面的所需功能.
ConfigTool和Utility主要负处理连库字符加密及其它工作.
DALFactory负责创建对象
就看Product这个类吧

 1 public   static  PetShop.IDAL.IProduct Create()  {
 2            
 3            /**//// Look up the DAL implementation we should be using
 4            string path = System.Configuration.ConfigurationSettings.AppSettings["WebDAL"];
 5            string className = path + ".Product";
 6            //PetShop.SQLServerDAL.Product
 7
 8            // Using the evidence given in the config file load the appropriate assembly and class
 9            return (PetShop.IDAL.IProduct)Assembly.Load(path).CreateInstance(className);
10        }

path值为PetShop.SQLServerDAL从web.config文件读取
主要负责创建PetShop.SQLServerDAL.Product这个类的实例;
 (PetShop.IDAL.IProduct)Assembly.Load(path).CreateInstance(className);
到了这里就可以看IDAL.IProduct这个接口

 1 public   interface  IProduct {
 2    
 3        /**//// <summary>
 4        /// Method to search products by category name
 5        /// </summary>
 6        /// <param name="category">Name of the category to search by</param>
 7        /// <returns>Interface to an arraylist of search results</returns>
 8        IList GetProductsByCategory(string category);
 9
10
11        /**//// <summary>
12        /// Method to search products by a set of keyword
13        /// </summary>
14        /// <param name="keywords">An array of keywords to search by</param>
15        /// <returns>Interface to an arraylist of search results</returns>
16        IList GetProductsBySearch(string[] keywords);
17    }

声明了两个方法.接口有了。当然要找实现接口的这个类.个人理解接口与类之间只是定义一种规则.接口内声明的方法,实现这个接口的类必须去实现接口里面的方法.假如在大型项目中有多人开发.可以有专门的人写好接口里面的方法.然后另外的人去写实现接口的类.可以做到分工明确.开发效率也会高点。好了.找到了实现接口的这个类.

 1 public   class  Product : IProduct {
 2
 3        //Static constants
 4        private const string SQL_SELECT_PRODUCTS = "SELECT ProductId, Name, Descn FROM Product";
 5        private const string SQL_SELECT_PRODUCTS_BY_CATEGORY = "SELECT ProductId, Name FROM Product WHERE Category = @Category";
 6        private const string SQL_SELECT_PRODUCTS_BY_SEARCH1 = "SELECT ProductId, Name, Descn FROM Product WHERE ((";
 7        private const string SQL_SELECT_PRODUCTS_BY_SEARCH2 = "LOWER(Name) LIKE '%' + {0} + '%' OR LOWER(Category) LIKE '%' + {0} + '%'";
 8        private const string SQL_SELECT_PRODUCTS_BY_SEARCH3 = ") OR (";
 9        private const string SQL_SELECT_PRODUCTS_BY_SEARCH4 = "))";
10        private const string PARM_CATEGORY = "@Category";
11        private const string PARM_KEYWORD = "@Keyword";
12
13        /**//// <summary>
14        /// Query for products by category
15        /// </summary>
16        /// <param name="category">category name</param>
17        /// <returns></returns>
18        public IList GetProductsByCategory(string category) {
19
20            IList productsByCategory = new ArrayList();
21
22            SqlParameter parm = new SqlParameter(PARM_CATEGORY, SqlDbType.Char, 10);
23            parm.Value = category;
24            
25            //Execute a query to read the products
26            using (SqlDataReader rdr = SQLHelper.ExecuteReader(SQLHelper.CONN_STRING_NON_DTC, CommandType.Text, SQL_SELECT_PRODUCTS_BY_CATEGORY, parm)) {
27                while (rdr.Read()){
28                    ProductInfo product = new ProductInfo(rdr.GetString(0), rdr.GetString(1), null);
29                    productsByCategory.Add(product);
30                }
31            }
32
33            return productsByCategory;
34        }
35
36        /**//// <summary>
37        /// Query for products by keywords. 
38        /// The results will include any product where the keyword appears in the category name or product name
39        /// </summary>
40        /// <param name="keywords">string array of keywords</param>
41        /// <returns></returns>
42        public IList GetProductsBySearch(string[] keywords) {
43            
44            IList productsBySearch = new ArrayList();
45
46            int numKeywords = keywords.Length;
47
48            //Create a new query string
49            StringBuilder sql = new StringBuilder(SQL_SELECT_PRODUCTS_BY_SEARCH1);
50
51            //Add each keyword to the query
52            for (int i = 0; i < numKeywords; i++) {
53                sql.Append(string.Format(SQL_SELECT_PRODUCTS_BY_SEARCH2, PARM_KEYWORD + i));
54                sql.Append(i + 1 < numKeywords ? SQL_SELECT_PRODUCTS_BY_SEARCH3 : SQL_SELECT_PRODUCTS_BY_SEARCH4);
55            }
56
57            string sqlProductsBySearch = sql.ToString();
58            SqlParameter[] parms = SQLHelper.GetCachedParameters(sqlProductsBySearch);
59            
60            // If the parameters are null build a new set
61            if (parms == null) {
62                parms = new SqlParameter[numKeywords];
63
64                for (int i = 0; i < numKeywords; i++)
65                    parms[i] = new SqlParameter(PARM_KEYWORD + i, SqlDbType.VarChar, 80);
66
67                SQLHelper.CacheParameters(sqlProductsBySearch, parms);
68            }
69
70            // Bind the new parameters
71            for (int i = 0; i < numKeywords; i++)
72                parms[i].Value = keywords[i];
73            
74            //Finally execute the query
75            using (SqlDataReader rdr = SQLHelper.ExecuteReader(SQLHelper.CONN_STRING_NON_DTC, CommandType.Text, sqlProductsBySearch, parms)) {
76                while (rdr.Read()){
77                    ProductInfo product = new ProductInfo(rdr.GetString(0), rdr.GetString(1), rdr.GetString(2));
78                    productsBySearch.Add(product);
79                }
80            }
81
82            return productsBySearch;
83        }
84    }

说实话,当初第一眼看里面的代码觉得眼花头昏,咋会这么乱呢.仔细一看.嗯.好处还是蛮多多的.仔细一分析,然后再对比以前自己写的东西.禁不住老脸都红了一下.呵呵。

1 private   const   string  SQL_SELECT_PRODUCTS  =   " SELECT ProductId, Name, Descn FROM Product " ;
2          private   const   string  SQL_SELECT_PRODUCTS_BY_CATEGORY  =   " SELECT ProductId, Name FROM Product WHERE Category = @Category " ;
3          private   const   string  SQL_SELECT_PRODUCTS_BY_SEARCH1  =   " SELECT ProductId, Name, Descn FROM Product WHERE (( " ;
4          private   const   string  SQL_SELECT_PRODUCTS_BY_SEARCH2  =   " LOWER(Name) LIKE '%' + {0} + '%' OR LOWER(Category) LIKE '%' + {0} + '%' " ;
5          private   const   string  SQL_SELECT_PRODUCTS_BY_SEARCH3  =   " ) OR ( " ;
6          private   const   string  SQL_SELECT_PRODUCTS_BY_SEARCH4  =   " )) " ;
7          private   const   string  PARM_CATEGORY  =   " @Category " ;
8          private   const   string  PARM_KEYWORD  =   " @Keyword " ;

上面这一段声明了对数据库操作所需的SQL语句.第一次编译后,下次直接调用.然后这个类实现了IDAL.IProduct这个类的方法.
Model这层主要是实现了实体层。
可能是语文小学的时候没学好的.表达得连我自己都觉得乱了呢.
web.config里面的

1      < add key = " SQLConnString1 "  value = " AQAAANCMnd8BFdERjHoAwE/Cl+sBAAAAiwM8Jc97B06fnNOg4m/cVAQAAAACAAAAAAADZgAAqAAAABAAAAC3dV/gT+/P3E69y1tuF6KtAAAAAASAAACgAAAAEAAAAJD/aFezVi9pgy9VPlwlXt1IAAAAQ/n2oxIiXxjnkg1gke77sbuNn++S/FOG0qiIxZcc1ft7U6xBrQIQEySfprnW/Xr2zjtwLubA4nLRh3C5/4r5VJ1f2Ri9jtpeFAAAAAK2kmoE+wHWuy2SV7AFaUdc4k1T "   />
2      < add key = " SQLConnString2 "  value = " AQAAANCMnd8BFdERjHoAwE/Cl+sBAAAAiwM8Jc97B06fnNOg4m/cVAQAAAACAAAAAAADZgAAqAAAABAAAADBe+0s4RDV1kFfEajzSk6yAAAAAASAAACgAAAAEAAAAO5mVnnO8ixwTntVMZz1OyhIAAAAy+dStcznTM4kq705oDiKVp1TkUw4mozYbuvp+BNXr4bN3rPzVbvbjgeYNE9RHa69rxUppvtb/YDRbj1oV2hsu5tX9dtIHik/FAAAAOpCMs+ujLIaxSalUd+bwkpNNBe6 "   />
3      < add key = " SQLConnString3 "  value = " AQAAANCMnd8BFdERjHoAwE/Cl+sBAAAAiwM8Jc97B06fnNOg4m/cVAQAAAACAAAAAAADZgAAqAAAABAAAACnoyDL679IUCTKmdAuovLtAAAAAASAAACgAAAAEAAAAMuza8eq1dAanascPjy/tr5YAAAAcJK4ehxVfY931JX9iG3TkPCYDqbKbUZ0Pp/OFNqJBNr313ije2WrKdqfPXWcERENx57wQ/IjSAnljOUzNdWAW2HPVERq6eMsbsz+l0P8xFJEMjOTEpNXbBQAAAB7TXfLAKGq+4CZ5ISo8Yngg6xczw== "   />
4      < add key = " OraConnString1 "  value = ""   />
5      < add key = " OraConnString2 "  value = ""   />
6      < add key = " OraConnString3 "  value = ""   />
7      < add key = " WebDAL "  value = " PetShop.SQLServerDAL "   />
8      < add key = " OrdersDAL "  value = " PetShop.SQLServerDAL "   />
9      < add key = " Event Log Source "  value = " .NET Pet Shop "   />

主要是存放连库字符串.和Factory所需的信息.刚刚不是说了下面这一段的么
 string path = System.Configuration.ConfigurationSettings.AppSettings["WebDAL"];
 5            string className = path + ".Product";
 6            //PetShop.SQLServerDAL.Product
 7
 8            // Using the evidence given in the config file load the appropriate assembly and class
 9            return (PetShop.IDAL.IProduct)Assembly.Load(path).CreateInstance(className);
只要把WebDAL改成OracleDAL就可以实现针对ORACLE数据库的操作.实现了多数据.娘的．真好.为啥我以前就没有想到呢.所以说书看得多.不如分析实例.边想边写.
还有差不多它的返回结果都IList类型.主要是用DataReader执行后的结果返回个另外的对象.这样做的话可以节省资源，小巧.不像自己以前动不动返回一个DataSet,要是应用到大项目中．不把服务器卡死才怪呢．

posted on 2006-10-22 14:03 我就是烟鬼 阅读( ...) 评论( ...) 编辑 收藏

转载于:https://www.cnblogs.com/paleyyang/archive/2006/10/22/536377.html