在分布式系统中，存在分布式事务的问题需要我们去解决，这是一个不可避免的问题，.Net中有一个开源的分布式框架可以供我们使用。我们先来看看它是如何使用的。
1-新建一个.Net Core3.1的WebApi项目
2-引入以下包
3-新建一个WebApi作为消息队列的发布方
PublishController
[Route("api/[controller]")]
[ApiController]
public class PublishController : ControllerBase
{
private readonly string ConnectionString = MyConst.mysqlCommectionString;//数据库连接地址
private readonly ICapPublisher _capBus;
public PublishController(ICapPublisher capPublisher)
{
_capBus = capPublisher;
}
[Route("adonet/transaction/publish")]
public IActionResult AdonetWithTransaction()
{
using (var connection = new MySqlConnection(ConnectionString))
{
using (var transaction = connection.BeginTransaction(_capBus, autoCommit: true))
{
//your business logic code
_capBus.Publish("product.services.time", DateTime.Now);//product.services.time为消息队列的名称
}
}
return Ok();
}
}
4-新建消息的订阅方
具体代码如下
public interface ISubscriberService
{
void ReceivedMessage(DateTime datetime);
}
public class SubscriberService : ISubscriberService, ICapSubscribe
{
[CapSubscribe("product.services.time")]
public void ReceivedMessage(DateTime datetime)
{
Console.WriteLine($"============{datetime}===========");
//throw new Exception($"异常重试!");
}
}
5-Startup.cs里面初始化DotNetCore.CAP框架内容
public class Startup
{
public Startup(IConfiguration configuration)
{
Configuration = configuration;
}
public IConfiguration Configuration { get; }
public void ConfigureServices(IServiceCollection services)
{
services.AddControllers();
services.AddTransient<ISubscriberService, SubscriberService>();
services.AddCap(x =>
{
x.UseMySql(MyConst.mysqlCommectionString);
x.UseRabbitMQ(options =>
{
options.UserName = "admin";//用户名
options.Password = "admin";//密码
options.HostName = "172.17.17.17";//rabbitmq ip
//options.Port = 15672;
});
x.UseDashboard();//DotNetCore.CAP框架管控台，地址是:http://localhost:端口/cap
});
}
// This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
if (env.IsDevelopment())
{
app.UseDeveloperExceptionPage();
}
app.UseRouting();
app.UseAuthorization();
app.UseEndpoints(endpoints =>
{
endpoints.MapControllers();
});
}
}
6-在数据库里面新建一个空的数据库，名字叫capdb,注意这个名字是可以自定义的，但注意在数据库连接地址的地址就要与你自定义的名字保持一致
7-我们请求地址
http://localhost:49237/api/Publish/adonet/transaction
8-这时订阅方即SubscriberService会收到消息
9-这时数据库里面会自动生成2张表，且里面会各自有一条数据，这表的作用可以认为就是分布式事务的事务日志表