Java调用post 上传文件带参

Java调用post上传文件带参可以使用Apache HttpComponents库来实现，具体步骤如下：

1. 引入HttpComponents库

<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
    <version>4.5.13</version>
</dependency>

2. 创建HttpPost请求

HttpPost httpPost = new HttpPost(url);

3. 创建MultipartEntityBuilder

MultipartEntityBuilder builder = MultipartEntityBuilder.create();

4. 添加文件参数

builder.addBinaryBody("file", file);

5. 添加其他参数

builder.addTextBody("param1", "value1");

6. 构建HttpEntity

HttpEntity entity = builder.build();

7. 设置请求实体

httpPost.setEntity(entity);

8. 执行请求

CloseableHttpClient httpClient = HttpClients.createDefault();
CloseableHttpResponse response = httpClient.execute(httpPost);

完整代码示例：

import org.apache.http.HttpEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.mime.MultipartEntityBuilder;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

import java.io.File;
import java.io.IOException;

public class HttpUpload {

    public static void main(String[] args) {
        String url = "http://localhost:8080/upload";
        File file = new File("test.txt");

        HttpPost httpPost = new HttpPost(url);
        MultipartEntityBuilder builder = MultipartEntityBuilder.create();
        builder.addBinaryBody("file", file);
        builder.addTextBody("param1", "value1");
        HttpEntity entity = builder.build();
        httpPost.setEntity(entity);

        try (CloseableHttpClient httpClient = HttpClients.createDefault();
             CloseableHttpResponse response = httpClient.execute(httpPost)) {
            HttpEntity responseEntity = response.getEntity();
            System.out.println(EntityUtils.toString(responseEntity));
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}