hutool工具

引入Hutool工具使用ExcelWriter，可以将数据写出到EXCEL
https://www.hutool.cn/docs/#/poi/Excel%E5%B7%A5%E5%85%B7-ExcelUtil

引入pom依赖

<dependency>
    <groupId>cn.hutool</groupId>
    <artifactId>hutool-all</artifactId>
    <version>5.7.20</version>
</dependency>
 <dependency>
     <groupId>org.apache.poi</groupId>
     <artifactId>poi-ooxml</artifactId>
     <version>4.1.2</version>
 </dependency>

后台

UserController.java–export接口

写一个export接口

/**
     * 导出接口
     */
    @GetMapping("/export")
    public void export(HttpServletResponse response) throws Exception {
        // 从数据库查询出所有的数据
        List<User> list = userService.list();
        // 通过工具类创建writer 写出到磁盘路径
//        ExcelWriter writer = ExcelUtil.getWriter(filesUploadPath + "/用户信息.xlsx");
        // 在内存操作，写出到浏览器
        ExcelWriter writer = ExcelUtil.getWriter(true);
        //自定义标题别名
        writer.addHeaderAlias("username", "用户名");
        writer.addHeaderAlias("password", "密码");
        writer.addHeaderAlias("nickname", "昵称");
        writer.addHeaderAlias("email", "邮箱");
        writer.addHeaderAlias("phone", "电话");
        writer.addHeaderAlias("address", "地址");
        writer.addHeaderAlias("createTime", "创建时间");
        writer.addHeaderAlias("avatarUrl", "头像");

        // 一次性写出list内的对象到excel，使用默认样式，强制输出标题
        writer.write(list, true);

        // 设置浏览器响应的格式
        response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet;charset=utf-8");
        String fileName = URLEncoder.encode("用户信息", "UTF-8");
        response.setHeader("Content-Disposition", "attachment;filename=" + fileName + ".xlsx");

        ServletOutputStream out = response.getOutputStream();
        writer.flush(out, true);
        out.close();
        writer.close();

    }

导出文件：
在这里插入图片描述

UserController.java–import接口

导入接口
记得在User实体类，里加入@ToString

/**
     * excel 导入
     * @param file
     * @throws Exception
     */
    @PostMapping("/import")
    public Boolean imp(MultipartFile file) throws Exception {
        InputStream inputStream = file.getInputStream();
        ExcelReader reader = ExcelUtil.getReader(inputStream);
        // 方式1：(推荐) 通过 javabean的方式读取Excel内的对象，但是要求表头必须是英文，跟javabean的属性要对应起来
//        List<User> list = reader.readAll(User.class);

        // 方式2：忽略表头的中文，直接读取表的内容
        List<List<Object>> list = reader.read(1);
        List<User> users = CollUtil.newArrayList();
        for (List<Object> row : list) {
            User user = new User();
            user.setUsername(row.get(0).toString());
            user.setPassword(row.get(1).toString());
            user.setNickname(row.get(2).toString());
            user.setEmail(row.get(3).toString());
            user.setPhone(row.get(4).toString());
            user.setAddress(row.get(5).toString());
            user.setAvatarUrl(row.get(6).toString());
            users.add(user);
        }

        userService.saveBatch(users);
        return true;
    }

导入文件记得把ID和创建时间列删掉
在这里插入图片描述

前端代码 User.vue

导入[element组件]

<el-upload action="http://localhost:9090/user/import" :show-file-list="false" accept="xlsx" :on-success="handleExcelImportSuccess" style="display: inline-block">
  <el-button type="primary" class="ml-5">导入 <i class="el-icon-bottom"></i></el-button>
</el-upload>

handleExcelImportSuccess() {
    this.$message.success("导入成功")
    this.load()
}

导出

<el-button type="primary" @click="exp" class="ml-5">导出 <i class="el-icon-top"></i></el-button>

exp() {
	window.open("http://localhost:9090/user/export")
}

完整代码

<template>
  <div>
    <div style="margin: 10px 0">
      <el-input style="width: 200px" placeholder="请输入名称" suffix-icon="el-icon-search" v-model="username"></el-input>
      <el-input style="width: 200px" placeholder="请输入邮箱" suffix-icon="el-icon-message" class="ml-5" v-model="email"></el-input>
      <el-input style="width: 200px" placeholder="请输入地址" suffix-icon="el-icon-position" class="ml-5" v-model="address"></el-input>
      <el-button class="ml-5" type="primary" @click="load">搜索</el-button>
      <el-button type="warning" @click="reset">重置</el-button>
    </div>

    <div style="margin: 10px 0">
      <el-button type="primary" @click="handleAdd">新增 <i class="el-icon-circle-plus-outline"></i></el-button>
      <el-popconfirm
          class="ml-5"
          confirm-button-text='确定'
          cancel-button-text='我再想想'
          icon="el-icon-info"
          icon-color="red"
          title="您确定批量删除这些数据吗？"
          @confirm="delBatch"
      >
        <el-button type="danger" slot="reference">批量删除 <i class="el-icon-remove-outline"></i></el-button>
      </el-popconfirm>
      <el-upload action="http://localhost:9090/user/import" :show-file-list="false" accept="xlsx" :on-success="handleExcelImportSuccess" style="display: inline-block">
        <el-button type="primary" class="ml-5">导入 <i class="el-icon-bottom"></i></el-button>
      </el-upload>
      <el-button type="primary" @click="exp" class="ml-5">导出 <i class="el-icon-top"></i></el-button>
    </div>

    <el-table :data="tableData" border stripe :header-cell-class-name="'headerBg'"  @selection-change="handleSelectionChange">
      <el-table-column type="selection" width="55"></el-table-column>
      <el-table-column prop="id" label="ID" width="80"></el-table-column>
      <el-table-column prop="username" label="用户名" width="140"></el-table-column>
      <el-table-column prop="nickname" label="昵称" width="120"></el-table-column>
      <el-table-column prop="email" label="邮箱"></el-table-column>
      <el-table-column prop="phone" label="电话"></el-table-column>
      <el-table-column prop="address" label="地址"></el-table-column>
      <el-table-column label="操作"  width="200" align="center">
        <template slot-scope="scope">
          <el-button type="success" @click="handleEdit(scope.row)">编辑 <i class="el-icon-edit"></i></el-button>
          <el-popconfirm
              class="ml-5"
              confirm-button-text='确定'
              cancel-button-text='我再想想'
              icon="el-icon-info"
              icon-color="red"
              title="您确定删除吗？"
              @confirm="del(scope.row.id)"
          >
            <el-button type="danger" slot="reference">删除 <i class="el-icon-remove-outline"></i></el-button>
          </el-popconfirm>
        </template>
      </el-table-column>
    </el-table>
    <div style="padding: 10px 0">
      <el-pagination
          @size-change="handleSizeChange"
          @current-change="handleCurrentChange"
          :current-page="pageNum"
          :page-sizes="[2, 5, 10, 20]"
          :page-size="pageSize"
          layout="total, sizes, prev, pager, next, jumper"
          :total="total">
      </el-pagination>
    </div>

    <el-dialog title="用户信息" :visible.sync="dialogFormVisible" width="30%" >
      <el-form label-width="80px" size="small">
        <el-form-item label="用户名">
          <el-input v-model="form.username" autocomplete="off"></el-input>
        </el-form-item>
        <el-form-item label="昵称">
          <el-input v-model="form.nickname" autocomplete="off"></el-input>
        </el-form-item>
        <el-form-item label="邮箱">
          <el-input v-model="form.email" autocomplete="off"></el-input>
        </el-form-item>
        <el-form-item label="电话">
          <el-input v-model="form.phone" autocomplete="off"></el-input>
        </el-form-item>
        <el-form-item label="地址">
          <el-input v-model="form.address" autocomplete="off"></el-input>
        </el-form-item>
      </el-form>
      <div slot="footer" class="dialog-footer">
        <el-button @click="dialogFormVisible = false">取 消</el-button>
        <el-button type="primary" @click="save">确 定</el-button>
      </div>
    </el-dialog>
  </div>
</template>

<script>
export default {
  name: "User",
  data() {
    return {
      tableData: [],
      total: 0,
      pageNum: 1,
      pageSize: 2,
      username: "",
      email: "",
      address: "",
      form: {},
      dialogFormVisible: false,
      multipleSelection: []
    }
  },
  created() {
    this.load()
  },
  methods: {
    load() {
      this.request.get("/user/page", {
        params: {
          pageNum: this.pageNum,
          pageSize: this.pageSize,
          username: this.username,
          email: this.email,
          address: this.address,
        }
      }).then(res => {
        console.log(res)

        this.tableData = res.records
        this.total = res.total

      })
    },
    save() {
      this.request.post("/user", this.form).then(res => {
        if (res) {
          this.$message.success("保存成功")
          this.dialogFormVisible = false
          this.load()
        } else {
          this.$message.error("保存失败")
        }
      })
    },
    handleAdd() {
      this.dialogFormVisible = true
      this.form = {}
    },
    handleEdit(row) {
      this.form = row
      this.dialogFormVisible = true
    },
    del(id) {
      this.request.delete("/user/" + id).then(res => {
        if (res) {
          this.$message.success("删除成功")
          this.load()
        } else {
          this.$message.error("删除失败")
        }
      })
    },
    handleSelectionChange(val) {
      console.log(val)
      this.multipleSelection = val
    },
    delBatch() {
      let ids = this.multipleSelection.map(v => v.id)  // [{}, {}, {}] => [1,2,3]
      this.request.post("/user/del/batch", ids).then(res => {
        if (res) {
          this.$message.success("批量删除成功")
          this.load()
        } else {
          this.$message.error("批量删除失败")
        }
      })
    },
    reset() {
      this.username = ""
      this.email = ""
      this.address = ""
      this.load()
    },
    handleSizeChange(pageSize) {
      console.log(pageSize)
      this.pageSize = pageSize
      this.load()
    },
    handleCurrentChange(pageNum) {
      console.log(pageNum)
      this.pageNum = pageNum
      this.load()
    },
    exp() {
      window.open("http://localhost:9090/user/export")
    },
    handleExcelImportSuccess() {
      this.$message.success("导入成功")
      this.load()
    }
  }
}
</script>


<style>
.headerBg {
  background: #eee!important;
}
</style>