1.1 request.js请求工具

//定制请求的实例

//导入axios  npm install axios
import axios from 'axios';
//定义一个变量,记录公共的前缀  ,  baseURL
const baseURL = '/api';
const instance = axios.create({baseURL})


//添加响应拦截器
instance.interceptors.response.use(
    result=>{
        return result.data;
    },
    err=>{
        alert('服务异常');
        return Promise.reject(err);//异步的状态转化成失败的状态
    }
)

export default instance;

2.1 编写注册接口

//导入request.js请求工具
import request from '@/utils/request.js'

//提供调用注册接口的函数
export const userRegisterService = (registerData)=>{
    //借助于UrlSearchParams完成传递
    const params = new URLSearchParams()
    for(let key in registerData){
        params.append(key,registerData[key]);
    }
    return request.post('/user/register',params);
}

3.1 编写页面

3.2 给表单绑定数据

3.3 定义表单校验规则

3.4 调用注册接口

```html
<script setup>
import { User, Lock } from '@element-plus/icons-vue'
import { ref } from 'vue'
//控制注册与登录表单的显示， 默认显示注册
const isRegister = ref(false)

//定义数据模型
const registerData = ref({
    username: '',
    password: '',
    rePassword: ''
})

//校验密码的函数
const checkRePassword = (rule, value, callback) => {
    if (value === '') {
        callback(new Error('请再次确认密码'))
    } else if (value !== registerData.value.password) {
        callback(new Error('请确保两次输入的密码一样'))
    } else {
        callback()
    }
}

//定义表单校验规则
const rules = {
    username: [
        { required: true, message: '请输入用户名', trigger: 'blur' },
        { min: 5, max: 16, message: '长度为5~16位非空字符', trigger: 'blur' }
    ],
    password: [
        { required: true, message: '请输入密码', trigger: 'blur' },
        { min: 5, max: 16, message: '长度为5~16位非空字符', trigger: 'blur' }
    ],
    rePassword: [
        { validator: checkRePassword, trigger: 'blur' }
    ]
}

//调用后台接口,完成注册
import { userRegisterService} from '@/api/user.js'
const register = async () => {
    //registerData是一个响应式对象,如果要获取值,需要.value
    let result = await userRegisterService(registerData.value);
    if (result.code === 0) {
        //成功了
        alert(result.msg ? result.msg : '注册成功');
    }else{
        //失败了
        alert('注册失败')
    } 
    //alert(result.msg ? result.msg : '注册成功');
    // ElMessage.success(result.msg ? result.msg : '注册成功')
}

</script>

<template>
    <el-row class="login-page">
        <el-col :span="12" class="bg"></el-col>
        <el-col :span="6" :offset="3" class="form">
            <!-- 注册表单 -->
            <el-form ref="form" size="large" autocomplete="off" v-if="isRegister" :model="registerData" :rules="rules">
                <el-form-item>
                    <h1>注册</h1>
                </el-form-item>
                <el-form-item prop="username">
                    <el-input :prefix-icon="User" placeholder="请输入用户名" v-model="registerData.username"></el-input>
                </el-form-item>
                <el-form-item prop="password">
                    <el-input :prefix-icon="Lock" type="password" placeholder="请输入密码"
                        v-model="registerData.password"></el-input>
                </el-form-item>
                <el-form-item prop="rePassword">
                    <el-input :prefix-icon="Lock" type="password" placeholder="请输入再次密码"
                        v-model="registerData.rePassword"></el-input>
                </el-form-item>
                <!-- 注册按钮 -->
                <el-form-item>
                    <el-button class="button" type="primary" auto-insert-space @click="register">
                        注册
                    </el-button>
                </el-form-item>
                <el-form-item class="flex">
                    <el-link type="info" :underline="false" @click="isRegister = false">
                        ← 返回
                    </el-link>
                </el-form-item>
            </el-form>
            <!-- 登录表单 -->
            <el-form ref="form" size="large" autocomplete="off" v-else>
                <el-form-item>
                    <h1>登录</h1>
                </el-form-item>
                <el-form-item>
                    <el-input :prefix-icon="User" placeholder="请输入用户名"></el-input>
                </el-form-item>
                <el-form-item>
                    <el-input name="password" :prefix-icon="Lock" type="password" placeholder="请输入密码"></el-input>
                </el-form-item>
                <el-form-item class="flex">
                    <div class="flex">
                        <el-checkbox>记住我</el-checkbox>
                        <el-link type="primary" :underline="false">忘记密码？</el-link>
                    </div>
                </el-form-item>
                <!-- 登录按钮 -->
                <el-form-item>
                    <el-button class="button" type="primary" auto-insert-space>登录</el-button>
                </el-form-item>
                <el-form-item class="flex">
                    <el-link type="info" :underline="false" @click="isRegister = true">
                        注册 →
                    </el-link>
                </el-form-item>
            </el-form>
        </el-col>
    </el-row>
</template>

<style lang="scss" scoped>
/* 样式 */
.login-page {
    height: 100vh;
    background-color: #fff;

    .bg {
        background: url('@/assets/logo2.png') no-repeat 60% center / 240px auto,
            url('@/assets/login_bg.jpg') no-repeat center / cover;
        border-radius: 0 20px 20px 0;
    }

    .form {
        display: flex;
        flex-direction: column;
        justify-content: center;
        user-select: none;

        .title {
            margin: 0 auto;
        }

        .button {
            width: 100%;
        }

        .flex {
            width: 100%;
            display: flex;
            justify-content: space-between;
        }
    }
}
</style>
```

3.1 跨域问题

3.1.1 修改request.js

//定制请求的实例

//导入axios  npm install axios
import axios from 'axios';
//定义一个变量,记录公共的前缀  ,  baseURL
const baseURL = '/api';
const instance = axios.create({baseURL})


//添加响应拦截器
instance.interceptors.response.use(
    result=>{
        return result.data;
    },
    err=>{
        alert('服务异常');
        return Promise.reject(err);//异步的状态转化成失败的状态
    }
)

export default instance;

3.1.2 修改vite.config.js

import { fileURLToPath, URL } from 'node:url'

import { defineConfig } from 'vite'
import vue from '@vitejs/plugin-vue'

// https://vitejs.dev/config/
export default defineConfig({
  plugins: [
    vue(),
  ],
  resolve: {
    alias: {
      '@': fileURLToPath(new URL('./src', import.meta.url))
    }
  },
  server:{
    proxy:{
      '/api':{//获取路径中包含了/api的请求
          target:'http://localhost:8080',//后台服务所在的源
          changeOrigin:true,//修改源
          rewrite:(path)=>path.replace(/^\/api/,'')///api替换为''
      }
    }
  }
})

4.1 测试