httpclient发送post请求 带文件与参数

要使用HttpClient发送带文件和参数的POST请求，您可以按照以下步骤进行操作：

1. 导入所需的类：

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.ContentType;
import org.apache.http.entity.mime.MultipartEntityBuilder;
import org.apache.http.entity.mime.content.FileBody;
import org.apache.http.entity.mime.content.StringBody;
import org.apache.http.impl.client.HttpClients;

2. 创建HttpClient实例：

HttpClient httpClient = HttpClients.createDefault();

3. 创建HttpPost请求对象：

HttpPost httpPost = new HttpPost(url);

其中，`url`是目标URL。

4. 创建MultipartEntityBuilder对象，并添加文件和参数：

MultipartEntityBuilder builder = MultipartEntityBuilder.create();
builder.addPart("file", new FileBody(file)); // 添加文件
builder.addPart("param1", new StringBody(param1, ContentType.TEXT_PLAIN)); // 添加参数1
builder.addPart("param2", new StringBody(param2, ContentType.TEXT_PLAIN)); // 添加参数2

其中，`file`是要上传的文件，`param1`和`param2`是需要传递的参数。

5. 构建HttpEntity并设置给HttpPost请求对象：

HttpEntity multipartEntity = builder.build();
httpPost.setEntity(multipartEntity);

6. 执行HttpPost请求并获取响应：

HttpResponse response = httpClient.execute(httpPost);

7. 处理响应结果：

int statusCode = response.getStatusLine().getStatusCode();
HttpEntity responseEntity = response.getEntity();
// 处理响应实体

完整的示例代码如下：

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.ContentType;
import org.apache.http.entity.mime.MultipartEntityBuilder;
import org.apache.http.entity.mime.content.FileBody;
import org.apache.http.entity.mime.content.StringBody;
import org.apache.http.impl.client.HttpClients;

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

public class HttpClientExample {
    public static void main(String[] args) {
        String url = "http://example.com/upload";
        String filePath = "/path/to/file";
        String param1 = "value1";
        String param2 = "value2";

        HttpClient httpClient = HttpClients.createDefault();
        HttpPost httpPost = new HttpPost(url);

        MultipartEntityBuilder builder = MultipartEntityBuilder.create();
        builder.addPart("file", new FileBody(new File(filePath)));
        builder.addPart("param1", new StringBody(param1, ContentType.TEXT_PLAIN));
        builder.addPart("param2", new StringBody(param2, ContentType.TEXT_PLAIN));

        HttpEntity multipartEntity = builder.build();
        httpPost.setEntity(multipartEntity);

        try {
            HttpResponse response = httpClient.execute(httpPost);
            int statusCode = response.getStatusLine().getStatusCode();
            HttpEntity responseEntity = response.getEntity();
            // 处理响应实体
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

请注意，上述示例中使用的是Apache HttpClient 4.x版本。在使用之前，请确保已经添加相关的依赖。