📄 random.jsp

📁 一本jsp自学教材
💻 JSP
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<%@ page contentType="text/html; charset=gb2312" %>
<%@ page language="java" %>
<%@ page import="com.mysql.jdbc.Driver" %>
<%@ page import="java.sql.*" %>
<HTML>
<head>
<title>Random Selection</title>
</head>
<BODY>
<%
  //驱动程序名、数据库用户名、密码、数据库名、表名
  String driverName="com.mysql.jdbc.Driver";  
  String username="root";  
  String password="yesterdayn";  
  String dbName="study";  
  String tableName="product";
  //联结字符串 
  String url="jdbc:mysql://localhost/"+dbName+"?characterEncoding=GBK";
try{
  //加载驱动程序
  Class.forName("com.mysql.jdbc.Driver");
  //建立同数据库的连接对象
  Connection connection=DriverManager.getConnection(url,username,password);
  Statement statement = connection.createStatement();  
  String sql="SELECT * FROM "+tableName;
  //发送执行SQL语句
  ResultSet rs = statement.executeQuery(sql); 
  //获取结果集中的总记录行数
  rs.last();
  double total=rs.getRow();
  //获取一个小于最大行的随机行号
  double u=(Math.random())*total;
  if(u<=0.5) //以防出现小于0.5的值而出错
  u=1;
  int p=(int)Math.round(u);  
  out.print("数据库连接成功！随机数为："+u+"  指针位置:"+p+"<BR>");  
  out.print("<TABLE BORDER=1 bordercolorlight=#000000 >");
  out.print("<TR><TD width=40>序号</TD>");
  out.print("<TD width=60>代码</TD><TD width=80>商品名称</TD>");
  out.print("<TD width=60>品牌</TD>");
  out.print("<TD width=150>产品简介</TD><TD width=80>存货数量</TD>");
  out.print("<TD width=80>价格/元</TD></TR>");
     rs.absolute(p);    //将记录指针指向第p行
     out.print("<TR>");
     out.print("<TD>"+rs.getInt(1)+"</TD>");
     out.print("<TD>"+rs.getString("pdm")+"</TD>");
     out.print("<TD>"+rs.getString("pname")+"</TD>");     
     out.print("<TD>"+rs.getString("provider")+"</TD>");
     out.print("<TD>"+rs.getString("info")+"</TD>");
     out.print("<TD>"+rs.getString("stock")+"</TD>");
     out.print("<TD>"+rs.getString("price")+"</TD>");
     out.print("</TR>");
  out.print("</TABLE>"); 
  rs.close();   
  statement.close();   
  connection.close();
 }
catch(SQLException e)
  {
   out.print(e.toString()); 
  }  
%>  
</HTML>
</BODY>
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