Spring Boot + Ajax前后端分离实现三级联动

引言

本项目为前后端分离的项目，前端采用Ajax技术，后端采用Spring Boot实现前后端分离，一个简单的案例，让你更加理解前后端分离的好处

需求描述

在静态页面写调用服务端接口，获取省、市、县区的数据

调用接口后显示在静态页面上，初始化时应该加载省份信息，当选择省份后，后面的加载出对应的市，选择市后，后面加载出对应的县区

当选中一个后，想切换另一个，需要将之前的选择数据清空再加载对应的数据

技术栈介绍：前端采用Ajax、Jquery、Bootstrap框架，后端采用SpringBoot

请求采用Ajax，后端皆为Post请求

效果图

在这里插入图片描述

数据表准备

t_province省份表

CREATE TABLE `t_county` (
  `id` int(255) DEFAULT NULL,
  `name` varchar(765) COLLATE utf8mb4_unicode_ci DEFAULT NULL,
  `parent_id` int(255) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci

t_city市区表

CREATE TABLE `t_city` (
  `id` varchar(16) COLLATE utf8mb4_unicode_ci DEFAULT NULL,
  `name` varchar(32) COLLATE utf8mb4_unicode_ci DEFAULT NULL,
  `parent_id` varchar(16) COLLATE utf8mb4_unicode_ci DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci

t_county县区表

CREATE TABLE `t_county` (
  `id` int(255) DEFAULT NULL,
  `name` varchar(765) COLLATE utf8mb4_unicode_ci DEFAULT NULL,
  `parent_id` int(255) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci

==注意：由于数据过大，我会上传sql文件至百度网盘，需要的小伙伴可以在文末下载哦~==

项目结构

后端结构

在这里插入图片描述

前端为一个html页面，引用了Bootstrap框架

注意：文末有百度网盘项目源码

核心源码

前端核心

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<link rel="stylesheet" href="bootstrap/css/bootstrap.min.css">
<body>
    <div style="padding: 20px;">
        <label>
            行政地区：
        </label>
        <div class="form-inline">
            <div class="form-group">
                <select id="province" class="form-control">
                    <option value="">请选择省</option>
                </select>
            </div>
            <div class="form-group" >
                <select id="city" class="form-control" onchange="loadCounty()">
                    <option value="">请选择市</option>
                </select>
            </div>
            <div class="form-group">
                <select id="county" class="form-control">
                    <option value="">请选择县区</option>
                </select>
            </div>
        </div>
    </div>
</body>
</html>
<script src="js/jquery-3.6.0.js"></script>
<script>
    //初始化时加载此函数
    $(function () {
        //初始化时加载所有省份
        loadProvince();

        //当选择省份后加载所选择省份的市区
        $("#province").change(function () {
            let obj = $("#province").val();
            let url = "http://localhost:8345/springbootajax/ajax4/list_city";
            let data = JSON.stringify({parent_id:obj});
            $.ajax({
                url,
                data,
                type:'post',
                contentType : 'application/json;charset=utf-8',
                success(res) {
                    //删除之前选择的记录
                    $("option").remove('.op1');
                    res.data.map((obj) => {
                        $("#city").append("<option class='op1' value='"+obj.id+"'>"+obj.name+"</option>")
                    })
                }
            })
        });

        //当市区选择后加载选择市区的县区
        $("#city").change(function () {
            let obj = $("#city").val();
            let url = "http://localhost:8345/springbootajax/ajax4/list_county";
            let data = JSON.stringify({parent_id:obj});
            $.ajax({
                url,
                data,
                type:'post',
                contentType : 'application/json;charset=utf-8',
                success(res) {
                    console.log(res);
                    //删除之前选择的记录
                    $("#county option").remove('.op1');
                    res.data.map((obj) => {
                        $("#county").append("<option class='op1' value='"+obj.id+"'>"+obj.name+"</option>")
                    })
                }
            })
        })
    })

    //加载所有省份
    function loadProvince() {
        let url = "http://localhost:8345/springbootajax/ajax4/list_province";
        let data = {};
        $.post(url, data, function (res) {
            res.data.map((obj) => {
                $("#province").append("<option value='"+obj.id+"'>"+obj.name+"</option>");
            })
        }, 'json');
    }
</script>

后端核心

pom依赖文件

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.6.2</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.wanshi</groupId>
    <artifactId>test_springboot</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>test_springboot</name>
    <description>test_springboot</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-starter-logging</artifactId>
                </exclusion>

            </exclusions>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-log4j</artifactId>
            <version>1.3.8.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-test</artifactId>
            <version>2.1.7.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
            <version>5.1.9.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>

        <dependency>
            <groupId>com.google.code.gson</groupId>
            <artifactId>gson</artifactId>
            <version>2.8.5</version>
        </dependency>


        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.1.20</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.1.2</version>
        </dependency>

        <dependency>
            <groupId>joda-time</groupId>
            <artifactId>joda-time</artifactId>
            <version>2.10.5</version>
        </dependency>

        <dependency>
            <groupId>commons-codec</groupId>
            <artifactId>commons-codec</artifactId>
            <version>1.11</version>
        </dependency>
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
            <version>3.9</version>
        </dependency>

        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi-ooxml</artifactId>
            <version>5.0.0</version>
        </dependency>

        <dependency>
            <groupId>com.googlecode.juniversalchardet</groupId>
            <artifactId>juniversalchardet</artifactId>
            <version>1.0.3</version>
        </dependency>


    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>

        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
                <filtering>false</filtering>
            </resource>
            <resource>
                <directory>src/main/resources</directory>
            </resource>
            <resource>
                <directory>libs/</directory>
                <targetPath>libs</targetPath>
                <includes>
                    <include>**/*.jar</include>
                </includes>
            </resource>
        </resources>
    </build>

</project>

ResultBean统一返回风格类

package com.wanshi.bean;

public class ResultBean<C> {

    private Integer code;

    private String msg;

    private C data;


    private ResultBean(Integer code, String msg, C data) {
        this.code = code;
        this.msg = msg;
        this.data = data;
    }

    public static ResultBean create(Integer code, String msg, Object data) {
        ResultBean res = new ResultBean(code, msg, data);
        return res;
    }

    public Integer getCode() {
        return code;
    }

    public void setCode(Integer code) {
        this.code = code;
    }

    public String getMsg() {
        return msg;
    }

    public void setMsg(String msg) {
        this.msg = msg;
    }

    public C getData() {
        return data;
    }

    public void setData(C data) {
        this.data = data;
    }
}

XingzhengMapper数据访问层

package com.wanshi.mapper;

import com.wanshi.bean.City;
import com.wanshi.bean.County;
import com.wanshi.bean.Province;
import org.apache.ibatis.annotations.Select;

import java.util.List;

public interface XingzhengMapper {

    @Select("select * from t_province")
    List<Province> listProvince();

    @Select("select * from t_city where parent_id = #{parent_id}")
    List<City> listCity(City param);

    @Select("select * from t_county where parent_id = #{parent_id}")
    List<County> listCounty(County param);
}

XingzhengService核心业务类

package com.wanshi.service;

import com.wanshi.bean.City;
import com.wanshi.bean.County;
import com.wanshi.bean.Province;
import com.wanshi.bean.ResultBean;
import com.wanshi.mapper.XingzhengMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class XingzhengService {

    @Autowired
    private XingzhengMapper xingzhengMapper;

    public ResultBean<List<Province>> listProvince() {
        List<Province> provinceList = xingzhengMapper.listProvince();
        return ResultBean.create(0, "success", provinceList);
    }

    public ResultBean<List<City>> listCity(City param) {
        List<City> provinceCityList = xingzhengMapper.listCity(param);
        return ResultBean.create(0, "success", provinceCityList);
    }

    public ResultBean<List<County>> listCounty(County param) {
        List<County> cityCountyList = xingzhengMapper.listCounty(param);
        return ResultBean.create(0, "success", cityCountyList);
    }
}

XingzhengController访问层类

package com.wanshi.controller;

import com.wanshi.bean.City;
import com.wanshi.bean.County;
import com.wanshi.bean.Province;
import com.wanshi.bean.ResultBean;
import com.wanshi.service.XingzhengService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.List;

@CrossOrigin
@RestController
@RequestMapping("/ajax4")
public class XingzhengController {

    @Autowired
    private XingzhengService xingzhengService;

    @PostMapping("/list_province")
    public ResultBean<List<Province>> listProvince() {
        ResultBean<List<Province>> res = xingzhengService.listProvince();
        return res;
    }

    @PostMapping("/list_city")
    public ResultBean<List<City>> listCity(@RequestBody City param) {
        ResultBean<List<City>> res = xingzhengService.listCity(param);
        return res;
    }

    @PostMapping("/list_county")
    public ResultBean<List<County>> listCounty(@RequestBody County param) {
        ResultBean<List<County>> res = xingzhengService.listCounty(param);
        return res;
    }

}

SpringBootRunApplication主启动类

@EnableTransactionManagement
//扫描mapper层的包存入springioc容器
@MapperScan("com.wanshi.mapper")
@SpringBootApplication
public class TestSpringbootApplication {

    public static void main(String[] args) {
        SpringApplication.run(TestSpringbootApplication.class, args);
    }

}

结语

本项目为前后端分离的一个小项目，项目不难，逻辑稍微有点复杂，但也是简单的，通过本项目，相信你不断的练习，注入实战开发，你的开发能力会有一个质的飞跃，加油~

项目源码地址（百度网盘）：https://pan.baidu.com/s/1dal4kZxxlGt6CSwZd9NWGg 提取码: jrqu

Spring Boot + Ajax前后端分离实现三级联动

Spring Boot + Ajax前后端分离实现三级联动

引言

需求描述

效果图

数据表准备

项目结构

核心源码

前端核心

后端核心

结语

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