java调用c#如何处理回调

发布时间:2024-12-01 15:30:21

阅读量:90

在Java中调用C#代码并处理回调，可以通过以下几种方式实现：

使用Java Native Interface (JNI)：通过JNI，你可以在Java代码中调用C#方法。首先，你需要在C#中创建一个Java Native Interface (JNI) 类，然后在Java代码中加载这个类并调用相应的方法。

C# 示例：

using System;
using System.Runtime.InteropServices;

public class JniWrapper
{
    [DllImport("kernel32.dll")]
    public static extern void Java_com_example_myapp_MyClass_nativeCallback(string message);

    public static void CallNativeCallback(string message)
    {
        nativeCallback(message);
    }
}

Java 示例：

public class MyClass {
    static {
        System.loadLibrary("jniwrapper");
    }

    public native void nativeCallback(String message);

    public static void main(String[] args) {
        MyClass myClass = new MyClass();
        myClass.nativeCallback("Hello from Java!");
    }
}

使用Web API或REST服务：如果你有一个C#后端服务，你可以创建一个Web API或REST服务，让Java客户端通过HTTP请求与C#后端进行通信。这种方法不需要在Java和C#之间直接调用，而是通过网络协议进行通信。

C# 示例（ASP.NET Core）：

using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;

[ApiController]
[Route("api/[controller]")]
public class MyController : ControllerBase
{
    [HttpPost]
    public async Task HandleRequest([FromBody] string message)
    {
        // 处理请求并调用回调方法
        await Task.Delay(1000);
        Console.WriteLine("Received message: " + message);
        return Ok();
    }
}

Java 示例：

import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.URL;

public class MyClient {
    public static void main(String[] args) {
        try {
            URL url = new URL("http://localhost:5000/api/my");
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            connection.setRequestMethod("POST");
            connection.setDoOutput(true);
            connection.setRequestProperty("Content-Type", "application/json; utf-8");

            String input = "{\"message\":\"Hello from Java!\"}";
            byte[] inputBytes = input.getBytes("utf-8");

            connection.setFixedLengthStreamingMode(inputBytes.length);
            try (OutputStream os = connection.getOutputStream()) {
                os.write(inputBytes);
            }

            int responseCode = connection.getResponseCode();
            System.out.println("Response Code: " + responseCode);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

使用gRPC： gRPC是一个高性能、开源的通用RPC框架，可以在Java和C#之间进行通信。首先，你需要定义一个.proto文件，然后使用gRPC工具生成Java和C#客户端和服务端代码。

示例.proto文件：

syntax = "proto3";

package mygrpc;

service MyService {
    rpc CallMyMethod (MyRequest) returns (MyResponse);
}

message MyRequest {
    string message = 1;
}

message MyResponse {
    string result = 1;
}

C# 示例（服务器端）：

using System;
using System.Threading.Tasks;
using Grpc.Core;

public class MyService : MyService.MyServiceBase
{
    public override Task CallMyMethod(MyRequest request, ServerCallContext context)
    {
        // 处理请求并调用回调方法
        Console.WriteLine("Received message: " + request.Message);
        return Task.FromResult(new MyResponse { Result = "Hello from C#" });
    }
}

Java 示例（客户端）：

import io.grpc.ManagedChannel;
import io.grpc.ManagedChannelBuilder;
import mygrpc.MyServiceGrpc;
import mygrpc.MyServiceOuterClass;

public class MyClient {
    public static void main(String[] args) throws Exception {
        ManagedChannel channel = ManagedChannelBuilder.forAddress("localhost", 50051).usePlaintext().build();
        MyServiceGrpc.MyServiceClient client = MyServiceGrpc.newClient(channel);

        MyServiceOuterClass.MyRequest request = MyServiceOuterClass.MyRequest.newBuilder().setMessage("Hello from Java!").build();
        MyServiceOuterClass.MyResponse response = client.callMyMethod(request);
        System.out.println("Response: " + response.getResult());

        channel.shutdown();
    }
}