.NET6 webapi JWT示例代码

以下是使用.NET 6 Web API实现JWT认证的示例代码：

1. 首先，安装所需的NuGet包：

dotnet add package Microsoft.AspNetCore.Authentication.JwtBearer
dotnet add package System.IdentityModel.Tokens.Jwt

2. 在Program.cs文件中进行配置：

using Microsoft.IdentityModel.Tokens;

var builder = WebApplication.CreateBuilder(args);

// 添加JWT认证服务
builder.Services.AddAuthentication(JwtBearerDefaults.AuthenticationScheme)
    .AddJwtBearer(options =>
    {
        options.TokenValidationParameters = new TokenValidationParameters
        {
            ValidateIssuer = true,
            ValidateAudience = true,
            ValidateLifetime = true,
            ValidateIssuerSigningKey = true,
            ValidIssuer = "your_issuer", // 发行者
            ValidAudience = "your_audience", // 受众
            IssuerSigningKey = new SymmetricSecurityKey(Encoding.UTF8.GetBytes("your_secret_key")) // 密钥
        };
    });

builder.Services.AddControllers();

var app = builder.Build();

app.UseAuthentication();
app.UseAuthorization();

app.MapControllers();

app.Run();

3. 创建一个控制器来处理认证请求：

using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;
using System;
using System.IdentityModel.Tokens.Jwt;
using System.Security.Claims;
using System.Text;
using Microsoft.IdentityModel.Tokens;

[Authorize]
[ApiController]
[Route("api/[controller]")]
public class AuthController : ControllerBase
{
    [AllowAnonymous]
    [HttpPost("login")]
    public IActionResult Login(string username, string password)
    {
        // 假设这里是验证用户名和密码的逻辑

        // 如果验证通过，创建一个JWT token并返回给客户端
        var token = GenerateToken(username);
        return Ok(new { token });
    }

    [HttpGet("protected")]
    public IActionResult Protected()
    {
        // 受保护的路由，只有经过认证的用户才能访问
        return Ok("You have accessed the protected route.");
    }

    private string GenerateToken(string username)
    {
        var claims = new[]
        {
            new Claim(ClaimTypes.Name, username),
            // 可以添加其他自定义的claims
        };

        var key = new SymmetricSecurityKey(Encoding.UTF8.GetBytes("your_secret_key"));
        var creds = new SigningCredentials(key, SecurityAlgorithms.HmacSha256);

        var token = new JwtSecurityToken(
            issuer: "your_issuer",
            audience: "your_audience",
            claims: claims,
            expires: DateTime.Now.AddMinutes(30), // token过期时间
            signingCredentials: creds);

        return new JwtSecurityTokenHandler().WriteToken(token);
    }
}

以上示例代码演示了如何使用.NET 6 Web API和JWT来实现身份认证。请注意替换示例中的"your_issuer"、"your_audience"和"your_secret_key"为适合你的实际情况的值。