Yii框架2使用表单进行文件上传的实例讲解

yii2用表单上传文件经常用到的，该怎样上传呢？

1、单个文件上传

首先建立一个模型models/UploadForm.php,内容如下

namespace appmodels;

use yiiaseModel;
use yiiwebUploadedFile;

/**
 * UploadForm is the model behind the upload form.
 */
class UploadForm extends Model
{
  /**
   * @var UploadedFile file attribute
   */
  public $file;

  /**
   * @return array the validation rules.
   */
  public function rules()
  {
    return [
      [['file'], 'file'],
    ];
  }
}

再建立一个视图文件，内容如下

<?php
use yiiwidgetsActiveForm;
?>

<?php $form = ActiveForm::begin(['options' => ['enctype' => 'multipart/form-data']]) ?>

<?= $form->field($model, 'file')->fileInput() ?>

<button>Submit</button>

<?php ActiveForm::end() ?>

最后建立控制器文件，内容如下

namespace appcontrollers;

use Yii;
use yiiwebController;
use appmodelsUploadForm;
use yiiwebUploadedFile;

class SiteController extends Controller
{
  public function actionUpload()
  {
    $model = new UploadForm();

    if (Yii::$app->request->isPost) {
      $model->file = UploadedFile::getInstance($model, 'file');

      if ($model->file && $model->validate()) {        
        $model->file->saveAs('uploads/' . $model->file->baseName . '.' . $model->file->extension);
      }
    }

    return $this->render('upload', ['model' => $model]);
  }
}

注意这里我们没有用model->load(...)，而是用了UploadedFile::getInstance(...)。区别是后者不会执行$model->validate()，所以需要手动的去执行$model->validate()来检验数据的合法性。如果检验通过了，上传的文件保存在uploads文件夹下，即web目录下的uploads里。

一些可选的配置选项

上传文件不能为空

public function rules()
{
  return [
    [['file'], 'file', 'skipOnEmpty' => false],
  ];
}

上传类型，不仅可以根据扩展名检验，还可以根据文件的内容进行检验

public function rules()
{
  return [
    [['file'], 'file', 'extensions' => 'jpg, png', 'mimeTypes' => 'image/jpeg, image/png',],
  ];
}

2、多文件上传

如果你想一次上传多个文件，只需调节几个参数就可以达到目的

Model：

class UploadForm extends Model
{
  /**
   * @var UploadedFile|Null file attribute
   */
  public $file;

  /**
   * @return array the validation rules.
   */
  public function rules()
  {
    return [
      [['file'], 'file', 'maxFiles' => 10], // <--- here!
    ];
  }
}

View：

<?php
use yiiwidgetsActiveForm;

$form = ActiveForm::begin(['options' => ['enctype' => 'multipart/form-data']]);
?>

<?= $form->field($model, 'file[]')->fileInput(['multiple' => true]) ?>

  <button>Submit</button>

<?php ActiveForm::end(); ?>

与单文件上传不同的是下面这句

$form->field($model, 'file[]')->fileInput(['multiple' => true])

Controller:

namespace appcontrollers;

use Yii;
use yiiwebController;
use appmodelsUploadForm;
use yiiwebUploadedFile;

class SiteController extends Controller
{
  public function actionUpload()
  {
    $model = new UploadForm();

    if (Yii::$app->request->isPost) {
      $model->file = UploadedFile::getInstances($model, 'file');

      if ($model->file && $model->validate()) {
        foreach ($model->file as $file) {
          $file->saveAs('uploads/' . $file->baseName . '.' . $file->extension);
        }
      }
    }

    return $this->render('upload', ['model' => $model]);
  }
}

这样就可以实现多文件上传了。

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