如何比較字符串數組變量與正常字符串變量

Question

我有兩個表Cart_table和product_table。我想要做的就是在車表中顯示最流行的項目，然後將其與自己的產品表，並顯示它在我的 頁面上與變量的匹配什麼我有問題

String c="",pna="",pty="",ppr="",stock="",imgpath=""; 
       //String myList = new String[10]; 
       int a = 0; 
       int result = 0,count = 0; 
       int setres; 
       int[] arr = new int[100000]; 

        int item_id=0; 
     data dt=new data(); 
     String item="",cartid="",user=""; 
     String[] prdid = new String[60]; 
     String[] comp = new String[60]; 
     int[] pr_id=new int[50]; 
     //item = "123"; 

     try{ 
      dt.st=dt.cn.createStatement(); 
        //String select="select cartid,user_regid,user_prod_id,quantity from cart_table"; 
        //String select="select cartid,user_regid,user_prod_id,quantity from cart_table"; 
        /*String select="select "+ 
          "cart_table.cartid,cart_table.user_regid,cart_table.user_prod_id,cart_table.quantity,cart_table.add_date,"+ 
          "customer_table.fname,customer_table.email "+ 
          "from cart_table "+ 
          "inner join customer_table "+ 
          "on cart_table.user_regid=customer_table.regid";*/ 
        //String select="select * from cart_table"; 
        String select_match="SELECT user_prod_id, COUNT(*) AS rep "+ 
             "FROM cart_table "+ 
             "GROUP BY user_prod_id "+ 
             "ORDER BY rep desc"; 
        dt.rs=dt.st.executeQuery(select_match); 

         while(dt.rs.next()){ 



           //String cid=dt.rs.getString("cartid"); 
           //String prid=dt.rs.getString("user_prod_id"); 
           prdid[a] = dt.rs.getString("user_prod_id"); 
           pr_id[a] = dt.rs.getInt("user_prod_id"); 
           String repp = dt.rs.getString("rep"); 
             //String date_add = dt.rs.getString("add_date"); 

           out.println("This is int"+pr_id[a]); 
           out.println("<br/>"+prdid[a]); 
           out.println(repp); 
           a=a+1; 
             } 
         out.println("<br/>---------xxx--------"); 
         a=0; 

         String select3="select "+ 
          "product_table.p_id,product_table.p_type,"+ 
          "product_type.pt_id,"+ 
          "product_table.p_name,product_table.imgpath,product_table.p_price,product_table.stock,product_table.add_date,"+ 
          "product_type.pt_name "+ 
          "from product_table "+ 
          "inner join product_type "+ 
          "on product_table.p_type=product_type.pt_id "+ 
          "order by product_table.add_date desc"+ 
          ""; 

         dt.rs=dt.st.executeQuery(select3); 
        a = 0; 
         while(dt.rs.next()){ 

           item_id=dt.rs.getInt("p_id"); 
           String itemm=dt.rs.getString("p_id"); 
           comp[a] = dt.rs.getString("p_id"); 
           String com = dt.rs.getString("p_id"); 
           pna=dt.rs.getString("p_name"); 
           pty=dt.rs.getString("pt_name"); 
           ppr=dt.rs.getString("p_price"); 
           stock=dt.rs.getString("stock"); 
           imgpath=dt.rs.getString("imgpath"); 
           //String comp = prdid[a]; 
           //out.println("<br/>a"+comp+"This is a compare value<br/>"); 
           //out.println("<br/>a"+prdid[a]+"This is an actual value<br/>"); 
           //if(pr_id[a] == item_id) 
           //if(Arrays.asList(pr_id).contains(item_id)) 

> 

           if(prdid[a].equals(com)) 
           { 




         %> 
         <li class="span3"> 
           <div class="product-box"> 
            <span class="sale_tag"></span>            
                     <a href="product_detail.jsp?prdid=<%=item_id%>"><img alt="" class="imdis" src="<% out.println(imgpath); %>"></a><br/> 
            <a href="product_detail.jsp?prdid=<%=item_id%>" class="title"><% out.println(pna); %></a><br/> 
            <a href="#" class="category"><% out.println(pty); %></a> 
                     <p> <% out.println(item_id); %></p> 
            <p class="price"><% out.println(ppr); %></p> 
           </div> 
          </li>  ` 


         <% 
           } 
           a = a+1; 
} 





    } 
    catch(Exception ex){ 
     out.println(ex); 
    } 

我的主要問題是與此代碼

if(prdid[a].equals(com)) 
           { 




         %> 
         <li class="span3"> 
           <div class="product-box"> 
            <span class="sale_tag"></span>            
                     <a href="product_detail.jsp?prdid=<%=item_id%>"><img alt="" class="imdis" src="<% out.println(imgpath); %>"></a><br/> 
            <a href="product_detail.jsp?prdid=<%=item_id%>" class="title"><% out.println(pna); %></a><br/> 
            <a href="#" class="category"><% out.println(pty); %></a> 
                     <p> <% out.println(item_id); %></p> 
            <p class="price"><% out.println(ppr); %></p> 
           </div> 
          </li>  ` 


         <% 
           } 

Answer 1

看起來諾曼，它應該工作如果你的編碼是好​​的。 比較之前嘗試獲取和比較每個字符串的字節數：

byte[] utf8Bytes1 = firstString.getBytes("UTF-8"); 
byte[] utf8Bytes2 = secondString.getBytes("UTF-8"); 

然後打印這些陣列和比較的字節數。 由於數據庫編碼或其他原因，在分享結果後，可能字節不相等。

Answer 2

都能跟得上我彪這樣的事情：

try { 
       String firstString = "test1"; 
        byte[] utf8Bytes1 = firstString.getBytes("UTF-8"); 
       String secondString = "test2"; 
       byte[] utf8Bytes2 = secondString.getBytes("UTF-8"); 
       for (int i = 0; i < utf8Bytes1.length; i++) { 
        System.out.println("from first string: " + utf8Bytes1[i]); 
       } 

       for (int i = 0; i < utf8Bytes2.length; i++) { 
        System.out.println("from second string: " + utf8Bytes2[i]); 
       } 
       } catch (UnsupportedEncodingException e) { 
        e.printStackTrace(); 
       }