.net core api 图片上传与加载

时间 2019-12-05

标签 core api 图片上传加载繁體版

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关于.net core API 图片上传与加载文件夹

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1.上传图片

1.配置Swagger 与文件夹、接口添加

1.创建.net core api 项目 下载 NuGet 包 Swashbuckle.AspNetCore 
2.进入 starup 中 ConfigureServices 配置 ，添加以下代码
3.点击项目右键属性->生成->XML 文档文件 ✔ 上，接着在取消显示警告添加1591->保存

services.AddSwaggerGen(s =>

           {

               s.SwaggerDoc("v1", new Info

               {

                   Title = "图片上传",

                   Description = "图片上传测试",

                   Version = "v1"

               });



               #region XML备注



               var basePath = Path.GetDirectoryName(AppContext.BaseDirectory);

               var imagePath = Path.Combine(basePath, "ImageDemo.xml");

               s.IncludeXmlComments(imagePath,true);



               #endregion

           });

4.进入 starup 中 Configure 配置 ，添加以下代码

app.UseSwagger();
app.UseSwaggerUI(s => s.SwaggerEndpoint("/swagger/v1/swagger.json", "v1版本"));

5.点击 Properties 编辑为下面

{
  /*"$schema": "http://json.schemastore.org/launchsettings.json",
  "iisSettings": {
    "windowsAuthentication": false, 
    "anonymousAuthentication": true, 
    "iisExpress": {
      "applicationUrl": "http://localhost:59623",
      "sslPort": 44385
    }
  },*/
  "profiles": {/*
    "IIS Express": {
      "commandName": "IISExpress",
      "launchBrowser": true,
      "launchUrl": "api/values",
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Development"
      }
    },*/
    "ImageDemo": {
      "commandName": "Project",
      "launchBrowser": true,
      "launchUrl": "swagger",
      "applicationUrl": "https://localhost:5001;http://localhost:5000",
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Development"
      }
    }
  }
}

6.运行项目，即可以看到结果，以上 Swagger 配置完毕

2.编写接口

添加三个文件夹前端
- Images 存储图片
  - 里面在设置一个名称为 6 的文件夹
- IRepositories 接口文件夹
  - 新建接口类 IImagesResource
- Repositories 实现类文件夹
  - 新建实现类 ImagesResource
实现类代码git

using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;

namespace ImageDemo.IRepositories
{
    public interface IImagesResource
    {
        /// <summary>
        /// 加载图片
        /// </summary>
        /// <param name="path">路径</param>
        /// <param name="name">图片名</param>
        /// <returns></returns>
        FileContentResult LoadingPhoto(string path, string name);

        /// <summary>
        /// 上传图片
        /// </summary>
        /// <param name="formFile">图片</param>
        /// <param name="path">路径</param>
        /// <param name="name">图片名字</param>
        /// <returns></returns>
        CustomStatusCode UpLoadPhoto(IFormFile formFile, string path);
    }
}

2.实现图片上传

先上代码
实现类总代码github

using System;
using System.IO;
using System.Linq;
using ImageDemo.IRepositories;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;

namespace ImageDemo.Repositories
{
    public class ImagesResource:ControllerBase,IImagesResource
    {
        public static string[] LimitPictureType = {".PNG", ".JPG", ".JPEG", ".BMP", ".ICO"};

        /// <summary>
        /// 加载图片
        /// </summary>
        /// <param name="path"></param>
        /// <param name="name"></param>
        /// <returns></returns>
        public FileContentResult LoadingPhoto(string path, string name)
        {
            path = Directory.GetCurrentDirectory() + path + name + ".jpeg";
            FileInfo fi=new FileInfo(path);
            if (!fi.Exists)
            {
                return null;
            }

            FileStream fs = fi.OpenRead();
            byte[] buffer=new byte[fi.Length];
            //读取图片字节流
            //从流中读取一个字节块，并在给定的缓冲区中写入数据。
            fs.Read(buffer, 0, Convert.ToInt32(fi.Length));
            var resource = File(buffer, "image/jpeg");
            fs.Close();
            return resource;
        }

        /// <summary>
        /// 上传图片
        /// </summary>
        /// <param name="formFile"></param>
        /// <param name="path">路劲</param>
        /// <returns></returns>
        public CustomStatusCode UpLoadPhoto(IFormFile formFile, string path)
        {
            CustomStatusCode code;
            var currentPictureWithoutExtension = Path.GetFileNameWithoutExtension(formFile.FileName);
            var currentPictureExtension = Path.GetExtension(formFile.FileName).ToUpper();
            path = Directory.GetCurrentDirectory() + path;
            if (LimitPictureType.Contains(currentPictureExtension))
            {
                if (!Directory.Exists(path))
                {
                    Directory.CreateDirectory(path);
                }

                string name = currentPictureWithoutExtension + ".jpeg";
                path += name;
                using (var fs=System.IO.File.Create(path))
                {
                    formFile.CopyTo(fs);
                    //Stream 都有 Flush() 方法，
                    //根据官方文档的说法
                    //“使用此方法将全部信息从基础缓冲区移动到其目标或清除缓冲区，或者同时执行这两种操做”
                    fs.Flush();
                }
                code = new CustomStatusCode
                {
                    Status = "200",
                    Message = $"图片 {name} 上传成功"
                };
                return code;
            }
            code = new CustomStatusCode
            {
                Status = "400",
                Message = $"图片上传失败，格式错误"
            };
            return code;
        }
    }
}

上面有个重点是实现类还继承了 ControllerBase，而且继承位置要在IImagesResource以前
其中 CustomStatusCode 类是信息返回类下面贴下数据库

namespace ImageDemo
{
    public class CustomStatusCode
    {
        public object Status;
        public object Message { get; set; }
        public object Data { get; set; }
    }
}

取出里面的上传图片代码json

/// <summary>
        /// 上传图片
        /// </summary>
        /// <param name="formFile">图片</param>
        /// <param name="path">路劲</param>
        /// <returns></returns>
        public CustomStatusCode UpLoadPhoto(IFormFile formFile, string path)
        {
            CustomStatusCode code;
            var currentPictureWithoutExtension = Path.GetFileNameWithoutExtension(formFile.FileName);
            var currentPictureExtension = Path.GetExtension(formFile.FileName).ToUpper();
            path = Directory.GetCurrentDirectory() + path;
            if (LimitPictureType.Contains(currentPictureExtension))
            {
                if (!Directory.Exists(path))
                {
                    Directory.CreateDirectory(path);
                }

                string name = currentPictureWithoutExtension + ".jpeg";
                path += name;
                using (var fs=System.IO.File.Create(path))
                {
                    formFile.CopyTo(fs);
                    //Stream 都有 Flush() 方法，
                    //根据官方文档的说法
                    //“使用此方法将全部信息从基础缓冲区移动到其目标或清除缓冲区，或者同时执行这两种操做”
                    fs.Flush();
                }
                code = new CustomStatusCode
                {
                    Status = "200",
                    Message = $"图片 {name} 上传成功"
                };
                return code;
            }
            code = new CustomStatusCode
            {
                Status = "400",
                Message = $"图片上传失败，格式错误"
            };
            return code;
        }

解释阶段windows

IFormFile
- 是上传的文件
var currentPictureWithoutExtension = Path.GetFileNameWithoutExtension(formFile.FileName);
- 获取没有后缀扩展名的文件名，如传过来的是 image.png,通过上面 currentPictureWithoutExtension = image
var currentPictureExtension = Path.GetExtension(formFile.FileName).ToUpper();
- 获得 formFile 的扩展名并将其大写
path = Directory.GetCurrentDirectory() + path;
- Directory.GetCurrentDirectory()获得当前程序的路劲，也就是和 Starup.cs 文件同等级的存在
string name = currentPictureWithoutExtension + “.jpeg”;
- 这段代码是为了保存图片将后缀名统一，由于提取图片须要后缀名，之后提取图片方便点，这是个很次的写法，当时没想到其余的方法，这个方法不怎么可取后面我会改，先留个坑
fs.Flush();
- 这个解释是看网上的说明
- Stream 都有 Flush() 方法，根据官方文档的说法“使用此方法将全部信息从基础缓冲区移动到其目标或清除缓冲区，或者同时执行这两种操做”api

3.加载图片

贴代码app

/// <summary>
       /// 加载图片
       /// </summary>
       /// <param name="path"></param>
       /// <param name="name"></param>
       /// <returns></returns>
       public FileContentResult LoadingPhoto(string path, string name)
       {
           path = Directory.GetCurrentDirectory() + path + name + ".jpeg";
           FileInfo fi=new FileInfo(path);
           if (!fi.Exists)
           {
               return null;
           }

           FileStream fs = fi.OpenRead();
           byte[] buffer=new byte[fi.Length];
           //读取图片字节流
           //从流中读取一个字节块，并在给定的缓冲区中写入数据。
           fs.Read(buffer, 0, Convert.ToInt32(fi.Length));
           var resource = File(buffer, "image/jpeg");
           fs.Close();
           return resource;
       }

File(buffer, “image/jpeg”)
- 这个方法继承自 ControllerBase 并非来自 using System.IO 中
- 至于怎样用 using System.IO; 把图片取出来…我还没学，望大佬教教

4.Controller 控制器

贴代码测试

using ImageDemo.Db;
using ImageDemo.IRepositories;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Logging;
using System.Collections.Generic;
using System.IO;

namespace ImageDemo.Controllers
{
[Route(“api/[controller]”)]
[ApiController]
public class ValuesController : ControllerBase
{
#region Inistial

private readonly DbContext _dbContext;
    private readonly IImagesResource _imagesResource;

    private readonly ILogger<ValuesController> _logger;

    public ValuesController(
        ILogger<ValuesController> logger,
        DbContext dbContext,
        IImagesResource imagesResource)
    {
        _logger = logger;
        _dbContext = dbContext;
        _imagesResource = imagesResource;
    }

    #endregion

    /// <summary>
    /// 批量上传图片
    /// </summary>
    /// <param name="file"></param>
    /// <param name="formCollection"></param>
    [HttpPost]
    public IActionResult Post([FromForm] IFormFileCollection formCollection)
    {
        IList<CustomStatusCode> code=new List<CustomStatusCode>();
            if (formCollection.Count > 0)
            foreach (IFormFile file in formCollection)
            {
                var currentCode=_imagesResource.UpLoadPhoto(file, @"\images\6\");
                code.Add(currentCode);
            }

            return StatusCode(200,code);
    }

    /// <summary>
    /// 获取图片
    /// </summary>
    /// <param name="imgName"></param>
    /// <returns></returns>
    [HttpGet]
    public IActionResult Get(string imgName)
    {
        var image = _imagesResource.LoadingPhoto("\\Images\\6\\", imgName);
        if (image == null)
        {
            _logger.LogInformation($"图片 {imgName} 不存在");
            var code = new CustomStatusCode
            {
                Status = "404",
                Message = $"图片 {imgName} 加载不存在"
            };
            return StatusCode(404, code);
        }

        return image;

        #region MyRegion

        /*string[] LimitPictureType =
            {".PNG", ".JPG", ".JPEG", ".BMP", ".GIF", ".ICO"};
        GetFileName(di);
        

        

        
        string path = Directory.GetCurrentDirectory()+ $@"\Images\6\{imgName}"+".jpeg";

        FileInfo fi = new FileInfo(path);
        FileStream fs = fi.OpenRead(); ;
        byte[] buffer = new byte[fi.Length];
        //读取图片字节流
        fs.Read(buffer, 0, Convert.ToInt32(fi.Length));
        var response = File(buffer, "image/jpeg");
        fs.Close();
        return response;
        */

        #endregion
    }

    private static IList<string> path = new List<string>(); //保存你图片名称
    DirectoryInfo di = new DirectoryInfo(Directory.GetCurrentDirectory()+@"\Images\6\");

    /// <summary>
    /// 加载目录内文件夹名
    /// </summary>
    /// <param name="info"></param>
    public static void GetFileName(DirectoryInfo info)
    {
        //获取该路径下的全部文件的列表
        FileInfo[] fileInfo = info.GetFiles();

        //开始获得图片名称
        foreach (FileInfo subinfo in fileInfo)
        {
            //判断扩展名是否相同
            // if (subinfo.Extension == extension)
            // {
            string strname = subinfo.Name; //获取文件名称

            path.Add(strname); //把文件名称保存在泛型集合中
            // }
        }
    }
}

}

5.想法，问题与 GitHub

问题：

上传图片能够多张上传，加载图片的方法原本也想多张加载，当时多张的话，图片就会变成字符串的形式，不知为什么，求解

若是不用 ControllerBse 中的 File 那么该如何向页面传递图片

有两个想法，朋友提的：

那个加载图片直接创建一个html网页，将图片放进去，前端这样能够访问图片，应该可行，不知效率怎样

那个改后缀的实属下策，能够用创建数据库，两列，一列存储图片名，一列存储图片后缀，存储的时候能够将图片的名字改下，若是是用户头像，能够改成用户 Id 这样数字就惟一了