jsp+servlet+javabean实现简单的查询
使用到的还是access数据库，采用不用配置数据源的方法连接access数据库，无需配置数据源的方法在上一篇随笔中有提到
首先是查询界面cha.jsp，接受两个变量，查询类别(condition)和查询的关键字(name)
<%@ page contentType="text/html; charset=gb2312" language="java" import="java.sql.*" errorPage="" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>无标题文档</title>
</head>
<body bgcolor="cyan">
<center>
<h1>请输入要查询的关键字</h1>
<form action="/test5/Book1" method="post">
请选择查询条件<select name="condition">
<option>作者</option>
<option selected="selected">书名</option>
</select>
请输入<input type="text" name="name" /><br />
<input type="submit" value="提交" />
</form>
</body>
</html>
之后是servlet部分，主要是检查查询的关键字是否为空
代码
package test;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
public class Book1 extends HttpServlet
{
public void init(ServletConfig config) throws ServletException
{
super.init(config);
}
public void service(HttpServletRequest request,HttpServletResponse response)throws ServletException,IOException
{
PrintWriter out=response.getWriter();
response.setContentType("text/html;charset=gb2312");
String condition=request.getParameter("condition");
String name=request.getParameter("name");
if(name.equals(""))
{
response.sendRedirect("cha.jsp");
}
else
{
HttpSession session=request.getSession(true);
session.setAttribute("condition",condition);
session.setAttribute("name",name);
response.sendRedirect("xian.jsp");
}
}
public void destroy()
{
}
}
接下来是实现数据库查询功能的javabean类
package test;
import java.sql.*;
import java.io.*;
import java.util.*;
public class BookCo
{
public String name,condition;
Connection con=null;
String strurl="jdbc:odbc:driver={Microsoft Access Driver (*.mdb)};DBQ=C:\\Program Files\\Apache Software Foundation\\tomcat 6.0\\webapps\\test5\\book.mdb";
Statement stmt=null;
ResultSet rs=null;
public BookCo()
{
name="";
condition="";
}
public void setKeyword(String s,String ss)
{
name=s;
condition=ss;
try
{
byte[] b=name.getBytes("iso-8859-1");
name=new String(b);
byte[] bb=condition.getBytes("iso-8859-1");
condition=new String(bb);
}
catch(Exception e){}
}
public ResultSet Boo()
{
String drivername="sun.jdbc.odbc.JdbcOdbcDriver";
String sql="select * from book";
try
{
Class.forName(drivername);
con=DriverManager.getConnection(strurl);
stmt=con.createStatement();
if(condition.equals("作者"))
{
sql="select * from book where book_author='"+name+"'";
}
if(condition.equals("书名"))
{
sql="select * from book where book_name='"+name+"'";
}
rs=stmt.executeQuery(sql);
}
catch (Exception e)
{
System.out.println("connection fail");
}
return rs;
}
}
最后是展示查询结果的jsp界面
<%@ page contentType="text/html; charset=gb2312" language="java" import="java.sql.*" errorPage="" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>无标题文档</title>
</head>
<%@ page import="test.BookCo" %>
<%@ page import="java.sql.*" %>
<body>
<jsp:useBean id="Co" class="test.BookCo" scope="application"></jsp:useBean>
<center>
<h1>图书信息</h1>
<table border="1" width="80%">
<th>书号</th><th>书名</th><th>作者</th><th>出版社</th><th>图书价格</th><th>出版日期</th>
<%
String name=(String)session.getAttribute("name");
String condition=(String)session.getAttribute("condition");
Co.setKeyword(name,condition);
//out.print(Co.name+Co.condition);
//out.print(Co.Boo());
ResultSet rs=Co.Boo();
while(rs.next())
{
out.print("<tr><td>"+rs.getInt(1)+"</td>");
out.print("<td>"+rs.getString(2)+"</td>");
out.print("<td>"+rs.getString(3)+"</td>");
out.print("<td>"+rs.getString(4)+"</td>");
out.print("<td>"+rs.getInt(5)+"</td>");
out.print("<td>"+rs.getString(6)+"</td></tr>");
}
rs.close();
%>
</table>
</center>
</body>
</html>
接下来的问题就是，如果我用<%=rs.getInt(1)%>来输出第一个字段的值时，会发生错误，我调试了很久也没有解决，
希望高手来帮我解决一下，谢谢
上面那个问题已经解决了，rs.getInt(1)这个函数是按顺序来取出数据库中的字段的，而且不能往回取，也就是只能取1次。
所以说如果<%=rs.getInt(1)%>这样的话。。前面out.print("<tr><td>"+rs.getInt(1)+"</td>");就不能写了，2个
只能选其一。
