本文实例为大家分享了HttpClient实现表单提交上传文件的具体代码，供大家参考，具体内容如下
需求：如何利用HttpClient，发起post请求，模拟表单提交，在后端上传文件？
上传文件接口：
/**
* 文件上传测试接口
* @return
*/
@PostMapping("/upload")
public Object uploadFileTest(@RequestParam("file") MultipartFile file, @RequestParam("file_name") String file_name, @RequestParam("file_code") String file_code) {
System.out.println(file_name "," file_code);
return "OK";
}启动后，可以通过postman进行调用，最后打印OK，表示接口可以调用通
然后就是正式编码环节了
首先引入需要的包：
<dependency> <groupId>org.apache.httpcomponents</groupId> <artifactId>httpmime</artifactId> <version>4.5.3</version> </dependency>
编写main方法，直接发起调用
public static String httpClientUploadFile(String url, File file) {
CloseableHttpClient httpClient = HttpClients.createDefault();
String result = "";
//每个post参数之间的分隔。随意设定，只要不会和其他的字符串重复即可。
String boundary = "--------------4585696313564699";
try {
//文件名
String fileName = file.getName();
HttpPost httpPost = new HttpPost(url);
//设置请求头
httpPost.setHeader("Content-Type", "multipart/form-data; boundary=" boundary);
//HttpEntity builder
MultipartEntityBuilder builder = MultipartEntityBuilder.create();
//字符编码
builder.setCharset(Charset.forName("UTF-8"));
//模拟浏览器
builder.setMode(HttpMultipartMode.BROWSER_COMPATIBLE);
builder.setContentType(ContentType.MULTIPART_FORM_DATA);
//boundary
builder.setBoundary(boundary);
//multipart/form-data
builder.addPart("file", new FileBody(file, ContentType.DEFAULT_BINARY));
// binary
//builder.addBinaryBody("name=\"file\"; filename=\"mysql.docx\"", new FileInputStream(file), ContentType.MULTIPART_FORM_DATA, fileName);// 文件流
//其他参数
//builder.addTextBody("file_name", fileName, ContentType.create("text/plain", Consts.UTF_8));
builder.addTextBody("file_name", fileName, ContentType.MULTIPART_FORM_DATA);
builder.addTextBody("file_code", "111111", ContentType.MULTIPART_FORM_DATA);
//HttpEntity
HttpEntity entity = builder.build();
httpPost.setEntity(entity);
// 执行提交
HttpResponse response = httpClient.execute(httpPost);
//响应
HttpEntity responseEntity = response.getEntity();
if (responseEntity != null) {
// 将响应内容转换为字符串
result = EntityUtils.toString(responseEntity, Charset.forName("UTF-8"));
}
} catch (IOException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
httpClient.close();
} catch (IOException e) {
e.printStackTrace();
}
}
System.out.println("result" result);
return result;
}
//main 方法
public static void main(String[] args) {
httpClientUploadFile("http://127.0.0.1:8080/test/tempA/upload",new File("e:/tmp/mysql.docx"));
}最后返回OK，调用成功
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持Devmax。