JAVA请求vllm的api服务报错Unsupported upgrade request、 Invalid HTTP request received.

环境：

vllm 0.8.5

java 17

Qwen3-32B-FP8

问题描述：

JAVA请求vllm的api服务报错Unsupported upgrade request、 Invalid HTTP request received.

WARNING:  Unsupported upgrade request.
INFO:      - "POST /v1/chat/completions HTTP/1.1" 400 Bad Request
WARNING:  Invalid HTTP request received.

服务端:

解决方案：

1.原来请求脚本

import okhttp3.*;public class VllmApiDemo (public static void main(String[] args) throws Exception {OkHttpClient client = new OkHttpClient();String json = "{"+ "\"model\": \"Qwen3-32B-FP8\","+ "\"messages\": [{\"role\": \"user\", \"content\": \"你好\")]"+ "}";RequestBody body = RequestBody.create(json, MediaType.parse("application/json"));Request request = new Request.Builder().url("http://192.168.16.2:8700/v1/chat/completions").post(body).build();Response response = client.newCall(request).execute();System.out.println(response.body().string());}
}

错误日志分析：

WARNING:  Unsupported upgrade request.
INFO:      - "POST /v1/chat/completions HTTP/1.1" 400 Bad Request
WARNING:  Invalid HTTP request received.

服务端提示请求格式有误，导致 400 错误。 Java 代码，有几处明显的语法和格式问题，可能导致请求体JSON格式不正确，服务端无法解析：

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1.代码语法错误

• 第一行 mport okhttp3.*; 应为 import okhttp3.*;
• 类定义括号用错了，应该是 { 而不是 (
• JSON 字符串中，messages 数组结尾用了 )]，应为 }]
• JSON 字符串最后的引号关闭处格式有问题

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2. 正确的 JSON 请求体应为

{"model": "Qwen3-32B-FP8","messages": [{"role": "user","content": "你好"}]
}

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3. 修正后的 Java 示例代码

import okhttp3.*;public class VllmApiDemo {public static void main(String[] args) throws Exception {OkHttpClient client = new OkHttpClient();String json = "{"+ "\"model\": \"Qwen3-32B-FP8\","+ "\"messages\": [{\"role\": \"user\", \"content\": \"你好\"}]"+ "}";RequestBody body = RequestBody.create(json, MediaType.parse("application/json"));Request request = new Request.Builder().url("http://192.168.16.2:8700/v1/chat/completions").post(body).build();Response response = client.newCall(request).execute();System.out.println(response.body().string());}
}

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4. 重点说明

• JSON格式正确，数组和对象括号匹配
• 类定义和import语句正确
• 请求地址和模型名称确认无误
• 请求体内容用 MediaType.parse("application/json") 指定媒体类型

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4. 建议调试步骤

• 你可以先用 curl 命令测试接口，确认服务端正常响应，例如：

curl -X POST http://192.168.16.2:8700/v1/chat/completions \
-H "Content-Type: application/json" \
-d '{"model":"Qwen3-32B-FP8","messages":[{"role":"user","content":"你好"}]}'

• 确认 curl 成功返回后，再运行 Java 程序。

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