例子7：更新记录——更新数据库中表的数据（JSP）_系统需要记录每一条记录更新时间和更新人jsp-优快云博客

本文展示了一个使用JSP和MySQL进行产品信息更新的示例，包括前端表单收集、后台数据处理及数据库更新过程。

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一、文件目录结构图示

二、运行效果显示

三、代码示例

index.jsp

<%@ page contentType="text/html;charset=GB2312" %>
<%@ taglib tagdir="/WEB-INF/tags" prefix="inquire"%>
<HTML><BODY ><FONT size=2>
<FORM action="newResult.jsp" method=post>
<table border=1>
<tr><td> 输入要更新的产品的产品号：</td>
<td><Input type="text" name="number"></td></tr>
<tr><td>输入新的名称：</td><td><Input type="text" name="name"></td></tr>
<tr><td>输入新的生产日期：</td><td><Input type="text" name="madeTime"></td></tr>
<tr><td>输入新的价格：</td><td><Input type="text" name="price"></td></tr>
</table>
<BR><Input type="submit" name="b" value="提交更新">
<BR>product表更新前的数据记录是：
<inquire:QueryTag  dataBaseName="warehouse"
                   tableName="product" 
                   user="root" password=""/> 
<BR> <%=queryResult %>
</Font></BODY></HTML>

newResult.jsp

<%@ page contentType="text/html;charset=GB2312" %>
<%@ taglib tagdir="/WEB-INF/tags" prefix="renew"%>
<%@ taglib tagdir="/WEB-INF/tags" prefix="inquire"%>
<HTML><BODY bgcolor=pink><Font size=2>
<% String nu=request.getParameter("number");
   String na=request.getParameter("name");
   String mT=request.getParameter("madeTime");
   String pr=request.getParameter("price");
   byte bb[]=na.getBytes("iso-8859-1");
   na=new String(bb);
%>
 <renew:NewRecord number="<%=nu%>"name="<%=na%>"madeTime="<%=mT%>"price="<%=pr%>"/> 
 <BR>product表更新后的数据记录是：
 <inquire:QueryTag  dataBaseName="warehouse"tableName="product"user="root"password=""/> 
<BR> <%= queryResult%>
</Font>
</BODY>
</HTML>

QueryTag.tag

<%@ tag pageEncoding="GB2312" %>
<%@ tag import="java.sql.*" %>
<%@ attribute name="dataBaseName" required="true" %>
<%@ attribute name="tableName" required="true" %> 
<%@ attribute name="user" required="true" %>  
<%@ attribute name="password" required="false" %>  
<%@ variable name-given="biao" scope="AT_END" %>
<%@ variable name-given="queryResult" scope="AT_END" %>
<%  StringBuffer result;     
    result=new StringBuffer();
    try{  Class.forName("com.mysql.jdbc.Driver");
    }
    catch(Exception e){} 
    Connection con;
    Statement sql; 
    ResultSet rs;
    try{  result.append("<table border=1>"); 
          String uri="jdbc:mysql://127.0.0.1/"+dataBaseName;
          con=DriverManager.getConnection(uri,user,password);
          DatabaseMetaData metadata=con.getMetaData();
          ResultSet rs1=metadata.getColumns(null,null,tableName,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();
          rs=sql.executeQuery("SELECT * FROM "+tableName);
          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("请输入正确的用户名和密码");
}
//返回对象queryResult： 
    jspContext.setAttribute("queryResult",new String(result)); 
    jspContext.setAttribute("biao",tableName);          //返回biao对象
%>

newRecord.tag

<%@ tag pageEncoding="GB2312" %>
<%@ tag import="java.sql.*" %>
<%@ attribute name="number" required="true" %>
<%@ attribute name="name" required="true" %>
<%@ attribute name="madeTime" required="true" %>
<%@ attribute name="price" required="true" %>
<%  float p=Float.parseFloat(price);
    String condition1="UPDATE product SET name= '"+name+
                   "' WHERE number="+"'"+number+"'" ,
           condition2="UPDATE product SET madeTime= '"+madeTime+
                   "' WHERE number="+"'"+number+"'",
           condition3="UPDATE product SET price= "+price+
                      " WHERE number="+"'"+number+"'" ;
    try{   Class.forName("com.mysql.jdbc.Driver");
    }
    catch(Exception e){} 
    Connection con;
    Statement sql; 
    ResultSet rs;
   try{  String uri=
        "jdbc:mysql://127.0.0.1/warehouse?"+
         "user=root&password=&characterEncoding=gbk";
         con=DriverManager.getConnection(uri);
         sql=con.createStatement();
         sql.executeUpdate(condition1);
         sql.executeUpdate(condition2);
         sql.executeUpdate(condition3);
         con.close();
   }
   catch(Exception e){
         out.print(""+e);
   }
%>