例子4：条件查询数据库中表的数据（JSP）_jsp+mysql+servlet实现页面输入条件查询-优快云博客

index.jsp

<%@ page language="java" import="java.util.*" pageEncoding="gb2312"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>My JSP 'index.jsp' starting page</title>
	<meta http-equiv="pragma" content="no-cache">
	<meta http-equiv="cache-control" content="no-cache">
	<meta http-equiv="expires" content="0">    
	<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
	<meta http-equiv="description" content="This is my page">
	<!--
	<link rel="stylesheet" type="text/css" href="styles.css">
	-->
  </head>
  
  <body>
  <form action="byNumber.jsp" Method="post">
   <br>根据产品号查询
   <br/>输入产品号：<input type=text name="number">
   <br/><br>
   <input type=submit name="g" value="提交">
   </form>
   <form action="byPrice.jsp" Method="post">
   <br/><br>
   根据价格查询
   <br></br>价格在<input type=text name="priceMin" size=8>
   至<input type=text name="priceMax"size=8>之间
   <input type=submit value="提交">
   </form>
  </body>
</html>

byNumber.jsp

<%@ page language="java" import="java.util.*" pageEncoding="gb2312"%>
<%@ taglib tagdir="/WEB-INF/tags" prefix="com"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>My JSP 'byNumber.jsp' starting page</title>
    
	<meta http-equiv="pragma" content="no-cache">
	<meta http-equiv="cache-control" content="no-cache">
	<meta http-equiv="expires" content="0">    
	<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
	<meta http-equiv="description" content="This is my page">
	<!--
	<link rel="stylesheet" type="text/css" href="styles.css">
	-->

  </head>
  
  <body>
   <% String number=request.getParameter("number");
   if(number==null)
      number ="";
   byte [] bb =number.getBytes("iso-8859-1");
   number=new String(bb);
%>
 <com:NumberCondition number="<%=number%>" /> 
 根据产品号<%=number%>查询到的记录:
<BR><%=queryResultByNumber%>
  </body>
</html>

byPrice,jsp

<%@ page contentType="text/html;charset=GB2312" %>
<%@ taglib tagdir="/WEB-INF/tags" prefix="inquire"%>
<HTML><BODY><Font size=2>
<% String min=request.getParameter("priceMin");
   String max=request.getParameter("priceMax");
%>
 <inquire:PriceCondition  priceMin="<%=min %>" priceMax="<%=max%>" />
 价格在<%=min%>至 <%=max%>之间的记录:
 <BR><%=queryResultByPrice%>  <%--queryResultByPrice是Tag文件返回的对象--%>
</Font></BODY></HTML>

NumberCondition.tag

<%@ tag pageEncoding="GB2312" %>
<%@ tag import="java.sql.*" %>
<%@ attribute name="number" required="true" %>
<%@ variable name-given="queryResultByNumber" scope="AT_END" %>
<%  StringBuffer result;
    result=new StringBuffer();
    try{   Class.forName("com.mysql.jdbc.Driver");
    }
    catch(Exception e){} 
    Connection con;
    Statement sql; 
    ResultSet rs;
    int n=0;
    try{  result.append("<table border=1>"); 
          String uri=
          "jdbc:mysql://127.0.0.1/warehouse?"+
          "user=root&password=&characterEncoding=gb2312";
          con=DriverManager.getConnection(uri);
          DatabaseMetaData metadata=con.getMetaData();
          ResultSet rs1=metadata.getColumns(null,null,"product",null);
          int 字段个数=0;
          result.append("<tr>");
          while(rs1.next()){
             字段个数++;
             String clumnName=rs1.getString(4);
             result.append("<td>"+clumnName+"</td>");
          }
          result.append("</tr>");
          sql=con.createStatement();
          String condition=
          "SELECT * FROM product Where number ='"+number+"'";
          rs=sql.executeQuery(condition);
          while(rs.next()){
             result.append("<tr>");
             for(int k=1;k<=字段个数;k++) 
               result.append("<td>"+rs.getString(k)+"</td>");
               result.append("</tr>");
          }
          result.append("</table>");
          con.close();
    }
    catch(SQLException e){
          result.append(e);
    }
    jspContext.setAttribute("queryResultByNumber",new String(result)); 
%>

PriceCondition.tag

<%@ tag pageEncoding="GB2312" %>
<%@ tag import="java.sql.*" %>
<%@ attribute name="priceMax" required="true" %>
<%@ attribute name="priceMin" required="true" %>
<%@ variable name-given="queryResultByPrice" scope="AT_END" %>
<%  float max=Float.parseFloat(priceMax);
    float min=Float.parseFloat(priceMin);
    StringBuffer result;
    result=new StringBuffer();
    try{   Class.forName("com.mysql.jdbc.Drive");
    }
    catch(Exception e){} 
    Connection con;
    Statement sql; 
    ResultSet rs;
    int n=0;
    try{  result.append("<table border=1>"); 
          String uri="jdbc:mysql://127.0.0.1/warehouse";
          con=DriverManager.getConnection(uri,"root","");
          DatabaseMetaData metadata=con.getMetaData();
          ResultSet rs1=metadata.getColumns(null,null,"product",null);
          int 字段个数=0;
          result.append("<tr>");
          while(rs1.next()){
             字段个数++;
             String clumnName=rs1.getString(4);
             result.append("<td>"+clumnName+"</td>");
          }
          result.append("</tr>");
          sql=con.createStatement();
          String condition=
         "SELECT * FROM product Where price <="+
          max+" AND "+"price >= "+min;
          rs=sql.executeQuery(condition);
          while(rs.next()){
             result.append("<tr>");
             for(int k=1;k<=字段个数;k++) 
                result.append("<td>"+rs.getString(k)+"</td>");
             result.append("</tr>");
           }
          result.append("</table>");
          con.close();
    }
    catch(SQLException e){
         result.append(e);
    }
    jspContext.setAttribute("queryResultByPrice",new String(result)); 
%>

文件目录结构显示：