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这篇文章主要介绍.Net Core开发如何实现图片文件上传下载功能,文中介绍的非常详细,具有一定的参考价值,感兴趣的小伙伴们一定要看完!
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当下.Net Core项目可是如雨后春笋一般发展起来,作为.Net大军中的一员,我热忱地拥抱了.Net Core并且积极使用其进行业务的开发,我们先介绍下.Net Core项目下实现文件上传下载接口。
一、开发环境
毋庸置疑,宇宙第一IDE VisualStudio 2017

二、项目结构
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FilesController 文件上传下载控制器
PictureController 图片上传下载控制器
Return_Helper_DG 返回值帮助类
三、关键代码
1、首先我们来看Startup.cs 这个是我们的程序启动配置类,在这里我们进行一系列的配置。
跨域配置:
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当然跨域少不了dll的引用,我们使用Nuget引用相关的引用包

服务器资源路径置换,这样可以防止客户端猜测服务端文件路径,制造一个虚拟的隐射进行访问,提高了安全性。
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Startup.cs的完整代码如下:
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.FileProviders;
using Microsoft.Extensions.Logging;
using System.IO;
namespace QX_Core.FilesCenter
{
public class Startup
{
public Startup(IHostingEnvironment env)
{
var builder = new ConfigurationBuilder()
.SetBasePath(env.ContentRootPath)
.AddJsonFile("appsettings.json", optional: false, reloadOnChange: true)
.AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true)
.AddEnvironmentVariables();
Configuration = builder.Build();
}
public IConfigurationRoot Configuration { get; }
// This method gets called by the runtime. Use this method to add services to the container.
public void ConfigureServices(IServiceCollection services)
{
// Add framework services.
services.AddMvc();
#region CORS
services.AddCors(options =>
{
options.AddPolicy("AllowSpecificOrigin",
builder => builder.WithOrigins("http://localhost:3997").AllowAnyHeader().AllowAnyOrigin().AllowAnyMethod());
});
#endregion
}
// This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
{
//loggerFactory.AddConsole(Configuration.GetSection("Logging"));
//loggerFactory.AddDebug();
app.UseMvc();
// Shows UseCors with named policy.
app.UseCors("AllowSpecificOrigin");
app.UseStaticFiles(new StaticFileOptions()
{
FileProvider = new PhysicalFileProvider(Path.Combine(Directory.GetCurrentDirectory(), @"wwwroot/Files")),
RequestPath = new PathString("/src")
});
}
}
}2、Return_Helper_DG类用户设置一个统一的返回值反馈到客户端
Return_Helper_DG类的代码如下:
using System.Net;
/**
* author:qixiao
* create:2017-5-19 15:15:05
* */
namespace QX_Core.FilesCenter.QX_Core.Helper
{
public abstract class Return_Helper_DG
{
public static object IsSuccess_Msg_Data_HttpCode(bool isSuccess, string msg, dynamic data, HttpStatusCode httpCode = HttpStatusCode.OK)
{
return new { isSuccess = isSuccess, msg = msg, httpCode = httpCode, data = data };
}
public static object Success_Msg_Data_DCount_HttpCode(string msg, dynamic data = null, int dataCount = 0, HttpStatusCode httpCode = HttpStatusCode.OK)
{
return new { isSuccess = true, msg = msg, httpCode = httpCode, data = data, dataCount = dataCount };
}
public static object Error_Msg_Ecode_Elevel_HttpCode(string msg, int errorCode = 0, int errorLevel = 0, HttpStatusCode httpCode = HttpStatusCode.InternalServerError)
{
return new { isSuccess = false, msg = msg, httpCode = httpCode, errorCode = errorCode, errorLevel = errorLevel };
}
}
}3、FilesController是我们的文件上传控制器接口,这里定义了对上传的文件的接收操作,并且在控制器上启用跨域配置
using Microsoft.AspNetCore.Cors;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Net.Http.Headers;
using QX_Core.FilesCenter.QX_Core.Helper;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
namespace QX_Core.FilesCenter.Controllers
{
//[Produces("application/json")]
[Route("api/[controller]")]
[EnableCors("AllowSpecificOrigin")]
public class FilesController : Controller
{
private IHostingEnvironment hostingEnv;
public FilesController(IHostingEnvironment env)
{
this.hostingEnv = env;
}
[HttpPost]
public IActionResult Post()
{
var files = Request.Form.Files;
long size = files.Sum(f => f.Length);
//size > 100MB refuse upload !
if (size > 104857600)
{
return Json(Return_Helper_DG.Error_Msg_Ecode_Elevel_HttpCode("files total size > 100MB , server refused !"));
}
List filePathResultList = new List();
foreach (var file in files)
{
var fileName = ContentDispositionHeaderValue.Parse(file.ContentDisposition).FileName.Trim('"');
string filePath = hostingEnv.WebRootPath + $@"\Files\Files\";
if (!Directory.Exists(filePath))
{
Directory.CreateDirectory(filePath);
}
fileName = Guid.NewGuid() + "." + fileName.Split('.')[1];
string fileFullName = filePath + fileName;
using (FileStream fs = System.IO.File.Create(fileFullName))
{
file.CopyTo(fs);
fs.Flush();
}
filePathResultList.Add($"/src/Files/{fileName}");
}
string message = $"{files.Count} file(s) /{size} bytes uploaded successfully!";
return Json(Return_Helper_DG.Success_Msg_Data_DCount_HttpCode(message, filePathResultList, filePathResultList.Count));
}
}
} 在上述的代码中,我们对上传的文件的大小进行了限制,并且对文件的大小进行反馈。
4、PictureController 图片上传控制器接口,类似于文件,不过对上传的图片类型进行了校验和限制
using Microsoft.AspNetCore.Cors;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Net.Http.Headers;
using QX_Core.FilesCenter.QX_Core.Helper;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
namespace QX_Core.FilesCenter.Controllers
{
//[Produces("application/json")]
[Route("api/[controller]")]
[EnableCors("AllowSpecificOrigin")]
public class PicturesController : Controller
{
private IHostingEnvironment hostingEnv;
string[] pictureFormatArray = { "png", "jpg", "jpeg", "bmp", "gif","ico", "PNG", "JPG", "JPEG", "BMP", "GIF","ICO" };
public PicturesController(IHostingEnvironment env)
{
this.hostingEnv = env;
}
[HttpPost]
public IActionResult Post()
{
var files = Request.Form.Files;
long size = files.Sum(f => f.Length);
//size > 100MB refuse upload !
if (size > 104857600)
{
return Json(Return_Helper_DG.Error_Msg_Ecode_Elevel_HttpCode("pictures total size > 100MB , server refused !"));
}
List filePathResultList = new List();
foreach (var file in files)
{
var fileName = ContentDispositionHeaderValue.Parse(file.ContentDisposition).FileName.Trim('"');
string filePath = hostingEnv.WebRootPath + $@"\Files\Pictures\";
if (!Directory.Exists(filePath))
{
Directory.CreateDirectory(filePath);
}
string suffix = fileName.Split('.')[1];
if (!pictureFormatArray.Contains(suffix))
{
return Json(Return_Helper_DG.Error_Msg_Ecode_Elevel_HttpCode("the picture format not support ! you must upload files that suffix like 'png','jpg','jpeg','bmp','gif','ico'."));
}
fileName = Guid.NewGuid() + "." + suffix;
string fileFullName = filePath + fileName;
using (FileStream fs = System.IO.File.Create(fileFullName))
{
file.CopyTo(fs);
fs.Flush();
}
filePathResultList.Add($"/src/Pictures/{fileName}");
}
string message = $"{files.Count} file(s) /{size} bytes uploaded successfully!";
return Json(Return_Helper_DG.Success_Msg_Data_DCount_HttpCode(message, filePathResultList, filePathResultList.Count));
}
}
} 到此,我们的文件图片上传代码已经全部完成,下面我们对文件上传的客户端进行实现
四、客户端的实现
客户端我们很简单地用jQuery Ajax的方式进行图片文件的提交,客户端代码的实现:
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五、代码测试
1.启动服务器

我们可以看到一个控制台和一个web自动启动,并且web显示默认的Values控制器的请求返回值。
2.图片上传
我们使用ajax的方式进行图片的上传操作,打开测试web页面,并且选择图片,点击上传,查看控制台返回的结果:

可以看到,一张图片上传成功!
输入返回的地址,我们可以看到成功访问到了图片,特别注意这里服务器路径的改变:
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多图片上传:


可见,多图片上传没有任何问题!
同样进行文件上传的测试:


同样,文件上传也没有任何问题!
以上是.Net Core开发如何实现图片文件上传下载功能的所有内容,感谢各位的阅读!希望分享的内容对大家有帮助,更多相关知识,欢迎关注创新互联行业资讯频道!