【JavaWeb】实现动态多条件查询
实体类对象：
package com.ysw.web.entity;
public class Book {
private Integer id; //编号
private String name; //书名
private Double price; //价格
private String category; //类型
private Integer pnum; //库存
private String imgurl; //图片路径
private String description; //描述
private String author; //作者
private Integer sales; //销售量
public Book() {
}
public Book(String name, Double price, String category, Integer pnum, String imgurl, String description, String author, Integer sales) {
this.name = name;
this.price = price;
this.category = category;
this.pnum = pnum;
this.imgurl = imgurl;
this.description = description;
this.author = author;
this.sales = sales;
}
public Book(Integer id, String name, Double price, String category, Integer pnum, String imgurl, String description, String author, Integer sales) {
this.id = id;
this.name = name;
this.price = price;
this.category = category;
this.pnum = pnum;
this.imgurl = imgurl;
this.description = description;
this.author = author;
this.sales = sales;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Double getPrice() {
return price;
}
public void setPrice(Double price) {
this.price = price;
}
public String getCategory() {
return category;
}
public void setCategory(String category) {
this.category = category;
}
public Integer getPnum() {
return pnum;
}
public void setPnum(Integer pnum) {
this.pnum = pnum;
}
public String getImgurl() {
return imgurl;
}
public void setImgurl(String imgurl) {
this.imgurl = imgurl;
}
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
public String getAuthor() {
return author;
}
public void setAuthor(String author) {
this.author = author;
}
public Integer getSales() {
return sales;
}
public void setSales(Integer sales) {
this.sales = sales;
}
@Override
public String toString() {
final StringBuffer sb = new StringBuffer("Book{");
sb.append("id=").append(id);
sb.append(", name='").append(name).append('\'');
sb.append(", price=").append(price);
sb.append(", category='").append(category).append('\'');
sb.append(", pnum=").append(pnum);
sb.append(", imgurl='").append(imgurl).append('\'');
sb.append(", description='").append(description).append('\'');
sb.append(", author='").append(author).append('\'');
sb.append(", sales=").append(sales);
sb.append('}');
return sb.toString();
}
}
Service层：
//多条件动态查询
public List search(Integer id, String name, Double maxPrice, Double minPrice,
String category, Integer maxPnum, Integer minPnum, String imgurl,
String description, String author, Integer maxSales,Integer minSales) {
return bookDao.search(id, name, maxPrice, minPrice, category, maxPnum, minPnum, imgurl,
description, author, maxSales, minSales);
} Dao层：
//复杂条件查询
public List search(Integer id, String name, Double maxPrice, Double minPrice,
String category, Integer maxPnum, Integer minPnum, String imgurl,
String description, String author, Integer maxSales,Integer minSales){
//这个是用于存储查询的结果的
List books = new ArrayList();
//这个用于存储查询的条件参数的
List list = new ArrayList();
Connection conn = null;
PreparedStatement pstmt = null;
ResultSet rs = null;
try {
//创建资源链接对象
conn = getConnection();
//定义sql语句
String sql = "select * from book where 1 = 1";
//书本编号不为空的时候
if (id != 0) {
sql = sql + " and id = ?";
list.add(id);
}
//去除掉姓名的空白位置
if (!"".equals(name.trim())){
sql = sql + " and name like ?";
list.add("%" + name.trim() + "%");
}
//最高价格
if (maxPrice != 0.0) {
sql = sql + " and price < ?";
list.add(maxPrice);
}
//最低价格
if (minPrice != 0.0) {
sql = sql + " and price > ?";
list.add(minPrice);
}
//如果类别名不为空
if (!"".equals(category.trim())) {
sql = sql + " and category like ?";
list.add("%" + category.trim() + "%");
}
//最大库存
if (maxPnum != 0) {
sql = sql + " and pnum < ?";
list.add(maxPnum);
}
//最小库存
if (minPnum != 0) {
sql = sql + " and pnum > ?";
list.add(minPnum);
}
//作品封面
if (!"".equals(imgurl.trim())) {
sql = sql + "and imgurl like ?";
list.add("%" + imgurl.trim() + "%");
}
//作品描述
if (!"".equals(description.trim())){
sql = sql + " and description like ?";
list.add("%" + description.trim() + "%");
}
//作者
if (!"".equals(author.trim())){
sql = sql + " and author like ?";
list.add("%" + author.trim() + "%");
}
//最大销量
if (maxSales != 0){
sql = sql + " and sales < ?";
list.add(maxSales);
}
//最低销量
if (minSales != 0){
sql = sql + " and sales > ?";
list.add(minSales);
}
//创建sql执行对象
pstmt = conn.prepareStatement(sql);
//给?参数进行赋值
if (list.size() > 0) {
for (int i = 0; i < list.size(); i++) {
pstmt.setObject(i+1,list.get(i));
}
}
//执行sql
rs = pstmt.executeQuery();
//遍历查询
while (rs.next()){
Book book = new Book();
book.setId(rs.getInt("id"));
book.setName(rs.getString("name"));
book.setPrice(rs.getDouble("price"));
book.setCategory(rs.getString("category"));
book.setPnum(rs.getInt("pnum"));
book.setImgurl(rs.getString("imgurl"));
book.setDescription(rs.getString("description"));
book.setAuthor(rs.getString("author"));
book.setSales(rs.getInt("sales"));
books.add(book);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
//关闭资源链接对象
close(rs,pstmt,conn);
}
//返回一个带有参数的list集合
return books;
} Jsp页面：
<%--
Created by IntelliJ IDEA.
User: Simon
Date: 2020/2/1
Time: 23:11
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
国际图书商城
国际图书商城
多条件动态查询
编号
书名
价格
类别
库存
封面
描述
作者
售量
<%--
使用foreach循环进行遍历输出
我们重新来理解一下foreach:
当我们在requestScope中传入一个books集合的时候，
我们的foreach容器就多了一个books集合,对其进行遍历也就是遍历books容器里面的每一个book对象
这样的话我们每一个book对象就可以通过"."的方式,把具体的属性值取出来,这里类似于mybatis
--%>
<%--
用于分页的：
--%>
<%--正常使用的/复杂查询使用的--%>
${vs.count}
${book.name}
${book.price}
${book.category}
${book.pnum}
${book.imgurl}
${book.description}
${book.author}
${book.sales}
<%--这里在路径上传了一个book的id=book.id过去给后台--%>
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共${pageBean.count}条记录,共${pageBean.totalPage}页
--%>
<%----%>
<%--上一页--%>
<%-- --%>
<%--第${pageBean.currentPage}页/共${pageBean.totalPage}页 --%>
<%----%>
<%--下一页>>--%>
<%----%>
<%--
--%>