• 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。

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  • 原文地址:https://www.cnblogs.com/cookies9/p/1892303.html
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