HttpClient 是JDK11提供的一個全新HTTP客戶端Api蒂阱，超級好用琳水。
Multipart 請求
HttpClient 并沒有提供 Multipart 請求體的構(gòu)建Api丽涩。但是可以使用apache的開源httpmime庫來進行構(gòu)建滋恬。
<!-- https://mvnrepository.com/artifact/org.apache.httpcomponents/httpmime -->
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpmime</artifactId>
<version>4.5.13</version>
</dependency>
構(gòu)建一個 MultipartBody
// 構(gòu)建Multipart請求
HttpEntity httpEntity = MultipartEntityBuilder.create()
// 表單數(shù)據(jù)
.addPart("name", new StringBody(UriUtils.encode("SpringBoot中文社區(qū)", StandardCharsets.UTF_8), ContentType.APPLICATION_FORM_URLENCODED))
// JSON數(shù)據(jù)
.addPart("info", new StringBody("{\"site\": \"https://springboot.io\", \"now\": 2021}", ContentType.APPLICATION_JSON))
// 文件數(shù)據(jù)
.addBinaryBody("file", file, ContentType.APPLICATION_OCTET_STREAM, "eclipse-jee-2019-12-R-win32-x86_64.zip")
.build();
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream((int) httpEntity.getContentLength());
// 把body寫入到內(nèi)存
httpEntity.writeTo(byteArrayOutputStream);
Multipart 請求可以一次性post多個子body幼苛，通常用來上傳本地磁盤上的文件超全。所以這種請求體可能會異常龐大。甚至內(nèi)存不能完整的存入整個請求體穷绵。那么這個時候有2種辦法可以解決。
- 先把構(gòu)建好的Body數(shù)據(jù)寫入到磁盤特愿，再通過IO磁盤數(shù)據(jù)仲墨，提交給服務器
- 使用管道流，在讀取磁盤數(shù)據(jù)進行body構(gòu)建的時候揍障，直接通過管道提交到遠程服務器
管道流
管道流目养，顧名思義，可以往一邊寫毒嫡，從另一邊讀癌蚁。
// 創(chuàng)建讀取流
PipedInputStream pipedInputStream = new PipedInputStream();
// 創(chuàng)建寫入流
PipedOutputStream pipedOutputStream = new PipedOutputStream();
// 連接寫入和讀取流
pipedInputStream.connect(pipedOutputStream);
通過往pipedOutputStream寫入數(shù)據(jù)，就可以在pipedInputStream 讀取兜畸。
不能使用單線程既讀又寫努释，因為讀寫都是阻塞方法。任何一方阻塞住了了咬摇，另一方就會一直處于等待狀態(tài)伐蒂，導致死鎖
完整Demo
客戶端
package io.springcloud.test;
import java.io.IOException;
import java.io.InputStream;
import java.io.PipedInputStream;
import java.io.PipedOutputStream;
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpRequest.BodyPublishers;
import java.net.http.HttpResponse;
import java.net.http.HttpResponse.BodyHandlers;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Paths;
import org.apache.http.HttpEntity;
import org.apache.http.entity.ContentType;
import org.apache.http.entity.mime.MultipartEntityBuilder;
import org.apache.http.entity.mime.content.StringBody;
import org.springframework.web.util.UriUtils;
public class MainTest {
public static void main(String[] args) throws Exception {
// 管道流
PipedInputStream pipedInputStream = new PipedInputStream();
PipedOutputStream pipedOutputStream = new PipedOutputStream();
pipedInputStream.connect(pipedOutputStream);
// 本地文件
InputStream file = Files.newInputStream(Paths.get("D:\\eclipse-jee-2019-12-R-win32-x86_64.zip"));
// 構(gòu)建Multipart請求
HttpEntity httpEntity = MultipartEntityBuilder.create()
// 表單數(shù)據(jù)
.addPart("name", new StringBody(UriUtils.encode("SpringBoot中文社區(qū)", StandardCharsets.UTF_8), ContentType.APPLICATION_FORM_URLENCODED))
// JSON數(shù)據(jù)
.addPart("info", new StringBody("{\"site\": \"https://springboot.io\", \"now\": 2021}", ContentType.APPLICATION_JSON))
// 文件數(shù)據(jù)
.addBinaryBody("file", file, ContentType.APPLICATION_OCTET_STREAM, "eclipse-jee-2019-12-R-win32-x86_64.zip")
.build();
// 異步寫入數(shù)據(jù)到管道流
new Thread(() -> {
try (file; pipedOutputStream){
httpEntity.writeTo(pipedOutputStream);
} catch (IOException e) {
e.printStackTrace();
}
}).start();
HttpClient httpClient = HttpClient.newHttpClient();
try (pipedInputStream){
// 創(chuàng)建請求和請求體
HttpRequest request = HttpRequest
.newBuilder(new URI("http://localhost/upload"))
// 設(shè)置ContentType
.header("Content-Type", httpEntity.getContentType().getValue())
.header("Accept", "text/plain")
// 從管道流讀取數(shù)據(jù)，提交給服務器
.POST(BodyPublishers.ofInputStream(() -> pipedInputStream))
.build();
// 執(zhí)行請求肛鹏，獲取響應
HttpResponse<String> responseBody = httpClient.send(request, BodyHandlers.ofString(StandardCharsets.UTF_8));
System.out.println(responseBody.body());
}
}
}
服務端
package io.springcloud.web.controller;
import java.nio.charset.StandardCharsets;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestPart;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.util.UriUtils;
import com.google.gson.JsonObject;
@RestController
@RequestMapping("/upload")
public class UploadController {
private static final Logger LOGGER = LoggerFactory.getLogger(UploadController.class);
@PostMapping
public Object upload (@RequestPart("file") MultipartFile file,
@RequestPart("info") JsonObject info,
@RequestPart("name") String name) {
LOGGER.info("file: name={}, size={}", file.getOriginalFilename(), file.getSize());
LOGGER.info("info: {}", info.toString());
LOGGER.info("name: {}", UriUtils.decode(name, StandardCharsets.UTF_8));
return ResponseEntity.ok("success");
}
}
啟動服務端后逸邦，執(zhí)行客戶端請求恩沛，服務端日志輸出
2021-09-24 13:38:15.067 INFO 2660 --- [ XNIO-1 task-1] i.s.web.controller.UploadController : file: name=eclipse-jee-2019-12-R-win32-x86_64.zip, size=369653147
2021-09-24 13:38:15.067 INFO 2660 --- [ XNIO-1 task-1] i.s.web.controller.UploadController : info: {"site":"https://springboot.io","now":2021}
2021-09-24 13:38:15.067 INFO 2660 --- [ XNIO-1 task-1] i.s.web.controller.UploadController : name: SpringBoot中文社區(qū)
