添加分类例子

最新推荐文章于 2021-04-28 21:26:37 发布

最新推荐文章于 2021-04-28 21:26:37 发布 · 123 阅读

文章标签：

#SQL #Oracle #CSS #JSP #Cache

本文介绍了一个使用Java Web技术实现的分类添加功能示例，包括数据库操作、动态页面更新等关键技术点。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

添加分类例子:

数据库语句(Oracle):（如父类’A_1’,子类’A_!_2’）

-- Create table
create table TESTCLASS
(
ID NUMBER not null,
CATE_ID VARCHAR2(50),
CATE_PIDVARCHAR2(50),
CATE_NAME VARCHAR2(50)
)
tablespace USERS
pctfree 10
initrans 1
maxtrans 255
storage
(
initial 64K
minextents 1
maxextents unlimited
);
-- Create/Recreate primary, unique and foreign key constraints
alter table TESTCLASS
add constraint TID_PK primary key (ID)
disable;

Index.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>

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>

<title>添加分类测试成功</title>

<!--

-->

var XMLHttpReq; //创建XMLHttpRequest对象

function createXMLHttpRequest() {

if(window.XMLHttpRequest) { //Mozilla 浏览器

XMLHttpReq = new XMLHttpRequest();

}

else if (window.ActiveXObject) { // IE浏览器

try {

XMLHttpReq = new ActiveXObject("Msxml2.XMLHTTP");

} catch(e){

try {

XMLHttpReq = new ActiveXObject("Microsoft.XMLHTTP");

} catch (e) {}

}

//发送请求函数

function sendRequest() {

createXMLHttpRequest();

var url = "optionsServlet";

XMLHttpReq.open("GET", url);

XMLHttpReq.onreadystatechange = processResponse;//指定响应函数

XMLHttpReq.send(null);// 发送请求

}

// 处理返回信息函数

function processResponse() {

if (XMLHttpReq.readyState == 4) { // 判断对象状态

if (XMLHttpReq.status == 200) { // 信息已经成功返回，开始处理信息

display();

setTimeout("sendRequest()", 10000); //10秒后刷新

} else { //页面不正常

window.alert("您所请求的页面有异常。");

}

// 显示更新数据信息的函数

function display() {

var optionsText = XMLHttpReq.responseText;

document.getElementById("selects").innerHTML = optionsText;

}

</script>

</head>

<td>

<div align="right">用户分类名：</div>

</td>

</tr>

<tr>

</tr>

</table>

</form>

</body>

</html>

addShow.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>

<%@ page import="cc.yiyao.dbConn.JdbcUtil,java.sql.*" %>

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>

<title>My JSP 'addShow.jsp' starting page</title>

<!--

-->

</head>

<body>

Connection conn = JdbcUtil.getConnection();

conn.setAutoCommit(false);

Statement stmt = conn.createStatement();

String dbCate_id = "";//将来数据库中插入的字段

String temp_cateid ="";

String cate_pid = request.getParameter("cate_pid");

String sqlSel = "select * from testClass where cate_pid = '"+cate_pid+"' order by id desc"; //(实际上只要返回一条记录,不过oracle不能用top1

ResultSet rs = null;

rs= stmt.executeQuery(sqlSel);

if(rs.next()){//有相同类别的数据,取出最大值，再加上1;

temp_cateid = rs.getString("cate_id");

//分离出数字,后再加1,如A_2_1,分离出最后一个数字，再加1。

int k = temp_cateid.lastIndexOf("_");

//获得最后一部分的数字

String strLastPart = temp_cateid.substring(k+1,temp_cateid.length());

out.println("strLastPart="+strLastPart);

//获得字符串的前一部分

String strFirstPart = temp_cateid.substring(0,k+1);

out.println("strFirstPart="+strFirstPart);

//将最后的数字加1,最后合起来

dbCate_id = strFirstPart + (Integer.parseInt(strLastPart)+1);

out.println("dbCate_id"+dbCate_id);

}else{

//没有相同类别的数据，初始化开始值

if(!cate_pid.equals("0")){//没有相同类别的数据(开始的子类别为父类别+”_1"，初始化开始值(select 中以"0"为开始,没有相同类别又等于0说明数据库中都没有数据)

dbCate_id = cate_pid+"_1";

}else{//说明数据库未插入 //select 中以"0"为开始,没有相同类别又等于0说明数据库中都没有数据

dbCate_id = "A_1";

}

String className = request.getParameter("cate_name");

String sql = "insert into testClass values (5,'"+dbCate_id+"','"+cate_pid+"','"+className+"')";

stmt.executeUpdate(sql);

conn.commit();

conn.setAutoCommit(true);

out.println("dbCate_id2"+dbCate_id);

if(stmt!= null) {

stmt.close();

}

if(conn!= null) {

conn.close();

}

</body>

</html>

Servlet:

package test;

import java.io.IOException;

import java.io.PrintWriter;

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.sql.Statement;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class RefreshOptionsServlet extends HttpServlet {

public RefreshOptionsServlet() {

super();

}

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

response.setContentType("text/html;charset=gb2312");

response.setHeader("Cache-Control", "no-cache");//注意设置页面不缓存，不然就看不到刷新的效果了！！

PrintWriter out = response.getWriter();

StringBuffer optionsText = new StringBuffer("");

Connection conn = null;

try {

Class.forName("oracle.jdbc.driver.OracleDriver");

conn = DriverManager.getConnection(

"jdbc:oracle:thin:@localhost:1521:Oracle1",

"system",

"system"

);

Statement stmt = conn.createStatement();

String sql = "select * from testClass";//sql = "select * from testClass where cate_pid = 0";

ResultSet rs = null;

rs = stmt.executeQuery(sql);

String cate_pid = ""; //父编号

String cate_name = ""; //名称

String cate_id = ""; //编号

String sql2 = "select * from testClass where cate_pid='";

optionsText = optionsText.append("<select name='cate_pid'><option value='0'>无</option>");

while(rs.next()){

cate_id = rs.getString("cate_id");

cate_name = rs.getString("cate_name");

cate_pid = rs.getString("cate_pid");

optionsText = optionsText.append("<option value='"+cate_id+"'>"+cate_name+"</option>");

}

} catch (ClassNotFoundException e) {

e.p