Web多级联动下拉框（从数据库中获取数据，MVC模式,使用的是tomcat）
一、文件位置
java代码的位置
二、先编写一个jsp页面用来跳转到多级下拉框的jsp页面
随便编一个就行了,这里就叫index.jsp
1.index.jsp
<%@ page language="java" pageEncoding="UTF-8"%>
<%@ page contentType="text/html;charset=UTF-8" import="edu.model.*" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
首页
跳转到下拉框页面
2.Xlk.jsp
<%@ page language="java" pageEncoding="UTF-8"%>
<%@ page contentType="text/html;charset=UTF-8" import="edu.model.*,java.util.*,java.sql.*" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
四级联动获取数据库数据
三、Controller.java代码
1.DdbControl.java
package edu.controller;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import org.json.JSONArray;
import org.json.JSONObject;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import edu.model.DBOper;
import edu.model.Ddb;
import edu.model.User;
@Controller
public class DdbControl {
//二级联动获取数据库数据
//一级下拉框
@RequestMapping("/view/ddbone")
public String ddbone(HttpServletRequest request,HttpServletResponse response) throws IOException, ClassNotFoundException, SQLException {
//调用javabean处理
Ddb d=new Ddb();
ArrayList list=d.two();
request.setAttribute("list", list);
return "Xlk.jsp";
}
//二级下拉框
@RequestMapping("/view/ddbtwo")
public String ddbtwo(HttpServletRequest request,HttpServletResponse response) throws Exception{
response.setContentType("text/json; charset=UTF-8");
//获取部门ID
int id = Integer.parseInt(request.getParameter("Id"));
PrintWriter out = null;
Ddb d=new Ddb();
try{
out = response.getWriter();
}catch(Exception e){
e.printStackTrace();
}
JSONArray array = new JSONArray();
JSONObject member = null;
try{
//根据种类的Id 来查找种类下的所有商品
List ClassesList = d.two2(id);
for(Ddb classes:ClassesList){
member = new JSONObject();
member.put("classId", classes.getId_Pmenu());
member.put("className", classes.getThing());
member.put("Id_Brand", classes.getId_brand()); //三级下拉框的索引
array.put(member);
}
}catch(Exception e){
e.printStackTrace();
}
out.print(array.toString());
return null;
}
//三级下拉框
@RequestMapping("/view/ddbthree")
public String ddbthree(HttpServletRequest request,HttpServletResponse response) throws Exception{
response.setContentType("text/json; charset=UTF-8");
//获取部门ID
int id = Integer.parseInt(request.getParameter("Id"));
PrintWriter out = null;
Ddb d=new Ddb();
try{
out = response.getWriter();
}catch(Exception e){
e.printStackTrace();
}
JSONArray array = new JSONArray();
JSONObject member = null;
try{
//根据种类的Id 来查找种类下的所有商品
List ClassesList = d.three(id);
for(Ddb classes:ClassesList){
member = new JSONObject();
member.put("classId", classes.getId_brand());
member.put("className", classes.getBrand());
member.put("Id_Model", classes.getId_model()); //四级下拉框的索引
array.put(member);
}
}catch(Exception e){
e.printStackTrace();
}
out.print(array.toString());
return null;
}
//四级下拉框
@RequestMapping("/view/ddbfour")
public String ddbfour(HttpServletRequest request,HttpServletResponse response) throws Exception{
response.setContentType("text/json; charset=UTF-8");
//获取部门ID
int id = Integer.parseInt(request.getParameter("Id"));
PrintWriter out = null;
Ddb d=new Ddb();
try{
out = response.getWriter();
}catch(Exception e){
e.printStackTrace();
}
JSONArray array = new JSONArray();
JSONObject member = null;
try{
//根据种类的Id 来查找种类下的所有商品
List ClassesList = d.four(id);
for(Ddb classes:ClassesList){
member = new JSONObject();
member.put("Id_Model", classes.getId_model());
member.put("className", classes.getModel());
member.put("id_no", classes.getId_no());
array.put(member);
}
}catch(Exception e){
e.printStackTrace();
}
out.print(array.toString());
return null;
}
}
四、model代码
1.Ddb.java
package edu.model;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
public class Ddb {
//四级联动获取数据库数据
private String kind;
private String thing;
private String brand;
private String model;
private int id_menu;
private int id_Pmenu;
private int id_brand;
private int id_model;
public String getBrand() {
return brand;
}
public void setBrand(String brand) {
this.brand = brand;
}
public String getModel() {
return model;
}
public void setModel(String model) {
this.model = model;
}
public int getId_brand() {
return id_brand;
}
public void setId_brand(int id_brand) {
this.id_brand = id_brand;
}
public int getId_model() {
return id_model;
}
public void setId_model(int id_model) {
this.id_model = id_model;
}
public String getKind() {
return kind;
}
public void setKind(String kind) {
this.kind = kind;
}
public String getThing() {
return thing;
}
public void setThing(String thing) {
this.thing = thing;
}
public int getId_Pmenu() {
return id_Pmenu;
}
public void setId_Pmenu(int id_Pmenu) {
this.id_Pmenu = id_Pmenu;
}
public int getId_menu() {
return id_menu;
}
public void setId_menu(int id_menu) {
this.id_menu = id_menu;
}
//查询种类(一级下拉框)
public ArrayList two() throws SQLException, ClassNotFoundException{
DBOper db=new DBOper();
String sql="select * from dbo.[kind] ";
ResultSet rs=db.exeQuery(sql);
ArrayList list=new ArrayList();
while(rs.next()){
Ddb d=new Ddb();
d.setId_menu(rs.getInt(1));
d.setKind(rs.getString(2));
list.add(d);
}
return list;
}
//查询名称(二级下拉框)
public ArrayList two2(int id_Pmenu) throws SQLException, ClassNotFoundException{
DBOper db=new DBOper();
// String sql="select * from dbo.[menu2] where id_Pmenu='"+id_Pmenu+"'";
String sql="select * from dbo.[thing] where id_Pmenu='"+id_Pmenu+"'";
ResultSet rs=db.exeQuery(sql);
ArrayList list=new ArrayList();
while(rs.next()){
Ddb d=new Ddb();
d.setId_Pmenu(rs.getInt(1));
d.setThing(rs.getString(2));
d.setId_brand(rs.getInt(3)); //加了一个三级下拉框
list.add(d);
}
return list;
}
//查询品牌(三级下拉框)
public ArrayList three(int id_brand) throws SQLException, ClassNotFoundException{
DBOper db=new DBOper();
String sql="select * from dbo.[brand] where id_brand='"+id_brand+"'";
ResultSet rs=db.exeQuery(sql);
ArrayList list=new ArrayList();
while(rs.next()){
Ddb d=new Ddb();
d.setId_brand(rs.getInt(1));
d.setBrand(rs.getString(2));
d.setId_model(rs.getInt(3)); //加了一个四级下拉框
list.add(d);
}
return list;
}
//查询型号(四级下拉框)
public ArrayList four(int id_model) throws SQLException, ClassNotFoundException{
DBOper db=new DBOper();
String sql="select * from dbo.[model] where id_model='"+id_model+"'";
ResultSet rs=db.exeQuery(sql);
ArrayList list=new ArrayList();
while(rs.next()){
Ddb d=new Ddb();
d.setId_model(rs.getInt(1));
d.setModel(rs.getString(2));
d.setId_no(rs.getInt(3));
list.add(d);
}
return list;
}
}
2.连接数据库(这里用的是SQL Server，所以需要SQL Server的JDBC驱动，如果是MySql就换成MySql的驱动)
DBOper.java
package edu.model;
import java.sql.*;
public class DBOper {
private String uri="jdbc:sqlserver://localhost:1433;DatabaseName=wjDB";//数据库名字叫wjDB，这里改成自己建的数据库名
private String user="sa";
private String password="sa";
private Connection con;
private Statement st;
private ResultSet rs;
//构造方法
public DBOper() throws ClassNotFoundException, SQLException{
Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
con=DriverManager.getConnection(uri,user,password);
}
//执行查询
public ResultSet exeQuery(String sql) throws SQLException{
st=con.createStatement();
rs=st.executeQuery(sql);
return rs;
}
//执行更新
public void exeUpdate(String sql) throws SQLException{
st=con.createStatement();
st.executeUpdate(sql);
}
}
五、相关配置文件
1.web.xml
index.jsp
org.springframework.web.context.ContextLoaderListener
contextConfigLocation
WEB-INF/applicationContext.xml
springMVC
org.springframework.web.servlet.DispatcherServlet
contextConfigLocation
WEB-INF/springMVC.xml
1
springMVC
*.do
2.springMVC.xml
3.applicationContext.xml
六、数据库中的表
1.kind表
2.thing表
3.brand表
4.model表
注意:后面三张表的第一个数字要和前一张表对应
以上代码都能从文件中找到
附上文件连接链接：https://pan.baidu.com/s/1EOaBxsvpcH_nPQKccXavtA
提取码：rney
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