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詳解Android中使用OkHttp發(fā)送HTTP的post請(qǐng)求的方法

更新時(shí)間：2016年07月13日 16:49:50 作者：成富

OkHttp(github.com/square/okhttp)是近來(lái)人氣迅速攀升的一款第三方安卓HTTP支持包,這里我們就來(lái)詳解Android中使用OkHttp發(fā)送HTTP的post請(qǐng)求的方法

HTTP POST 和 PUT 請(qǐng)求可以包含要提交的內(nèi)容。只需要在創(chuàng)建 Request 對(duì)象時(shí)，通過(guò) post 和 put 方法來(lái)指定要提交的內(nèi)容即可。
HTTP POST 請(qǐng)求的基本示例：

public class PostString {
  public static void main(String[] args) throws IOException {
  OkHttpClient client = new OkHttpClient();
  MediaType MEDIA_TYPE_TEXT = MediaType.parse("text/plain");
  String postBody = "Hello World";

  Request request = new Request.Builder()
      .url("http://www.baidu.com")
      .post(RequestBody.create(MEDIA_TYPE_TEXT, postBody))
      .build();

  Response response = client.newCall(request).execute();
  if (!response.isSuccessful()) {
    throw new IOException("服務(wù)器端錯(cuò)誤: " + response);
  }

  System.out.println(response.body().string());
  }
}

以 String 類型提交內(nèi)容只適用于內(nèi)容比較小的情況。當(dāng)請(qǐng)求內(nèi)容較大時(shí)，應(yīng)該使用流來(lái)提交。

Post方式提交流

以流的方式POST提交請(qǐng)求體。請(qǐng)求體的內(nèi)容由流寫入產(chǎn)生。這個(gè)例子是流直接寫入 Okio 的BufferedSink。你的程序可能會(huì)使用 OutputStream ，你可以使用 BufferedSink.outputStream() 來(lái)獲取。

public static final MediaType MEDIA_TYPE_MARKDOWN
 = MediaType.parse("text/x-markdown; charset=utf-8");

private final OkHttpClient client = new OkHttpClient();

public void run() throws Exception {
 RequestBody requestBody = new RequestBody() {
  @Override public MediaType contentType() {
   return MEDIA_TYPE_MARKDOWN;
  }

  @Override public void writeTo(BufferedSink sink) throws IOException {
   sink.writeUtf8("Numbers\n");
   sink.writeUtf8("-------\n");
   for (int i = 2; i <= 997; i++) {
  sink.writeUtf8(String.format(" * %s = %s\n", i, factor(i)));
   }
  }

  private String factor(int n) {
   for (int i = 2; i < n; i++) {
  int x = n / i;
  if (x * i == n) return factor(x) + " × " + i;
   }
   return Integer.toString(n);
  }
 };

 Request request = new Request.Builder()
   .url("https://api.github.com/markdown/raw")
   .post(requestBody)
   .build();

 Response response = client.newCall(request).execute();
 if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);

 System.out.println(response.body().string());
}

Post方式提交文件

以文件作為請(qǐng)求體是十分簡(jiǎn)單的。

public static final MediaType MEDIA_TYPE_MARKDOWN
 = MediaType.parse("text/x-markdown; charset=utf-8");

private final OkHttpClient client = new OkHttpClient();

public void run() throws Exception {
 File file = new File("README.md");

 Request request = new Request.Builder()
   .url("https://api.github.com/markdown/raw")
   .post(RequestBody.create(MEDIA_TYPE_MARKDOWN, file))
   .build();

 Response response = client.newCall(request).execute();
 if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);

 System.out.println(response.body().string());
}

Post方式提交表單

使用 FormEncodingBuilder 來(lái)構(gòu)建和HTML <form> 標(biāo)簽相同效果的請(qǐng)求體。鍵值對(duì)將使用一種HTML兼容形式的URL編碼來(lái)進(jìn)行編碼。

private final OkHttpClient client = new OkHttpClient();

public void run() throws Exception {
 RequestBody formBody = new FormEncodingBuilder()
   .add("search", "Jurassic Park")
   .build();
 Request request = new Request.Builder()
   .url("https://en.wikipedia.org/w/index.php")
   .post(formBody)
   .build();

 Response response = client.newCall(request).execute();
 if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);

 System.out.println(response.body().string());
}

Post方式提交分塊請(qǐng)求

MultipartBuilder 可以構(gòu)建復(fù)雜的請(qǐng)求體，與HTML文件上傳形式兼容。多塊請(qǐng)求體中每塊請(qǐng)求都是一個(gè)請(qǐng)求體，可以定義自己的請(qǐng)求頭。這些請(qǐng)求頭可以用來(lái)描述這塊請(qǐng)求，例如他的 Content-Disposition 。如果 Content-Length 和 Content-Type 可用的話，他們會(huì)被自動(dòng)添加到請(qǐng)求頭中。

private static final String IMGUR_CLIENT_ID = "...";
private static final MediaType MEDIA_TYPE_PNG = MediaType.parse("image/png");

private final OkHttpClient client = new OkHttpClient();

public void run() throws Exception {
 // Use the imgur image upload API as documented at https://api.imgur.com/endpoints/image
 RequestBody requestBody = new MultipartBuilder()
   .type(MultipartBuilder.FORM)
   .addPart(
     Headers.of("Content-Disposition", "form-data; name=\"title\""),
     RequestBody.create(null, "Square Logo"))
   .addPart(
     Headers.of("Content-Disposition", "form-data; name=\"image\""),
     RequestBody.create(MEDIA_TYPE_PNG, new File("website/static/logo-square.png")))
   .build();

 Request request = new Request.Builder()
   .header("Authorization", "Client-ID " + IMGUR_CLIENT_ID)
   .url("https://api.imgur.com/3/image")
   .post(requestBody)
   .build();

 Response response = client.newCall(request).execute();
 if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);

 System.out.println(response.body().string());
}

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