详解Android中使用OkHttp发送HTTP的post请求的方法
HTTP POST 和 PUT 请求可以包含要提交的内容。只需要在创建 Request 对象时,通过 post 和 put 方法来指定要提交的内容即可。
HTTP POST 请求的基本示例:
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("服务器端错误: " + response); } System.out.println(response.body().string()); } }
以 String 类型提交内容只适用于内容比较小的情况。当请求内容较大时,应该使用流来提交。
Post方式提交流
以流的方式POST提交请求体。请求体的内容由流写入产生。这个例子是流直接写入 Okio 的BufferedSink。你的程序可能会使用 OutputStream ,你可以使用 BufferedSink.outputStream() 来获取。
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
以文件作为请求体是十分简单的。
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方式提交表单
使用 FormEncodingBuilder 来构建和HTML <form> 标签相同效果的请求体。键值对将使用一种HTML兼容形式的URL编码来进行编码。
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方式提交分块请求
MultipartBuilder 可以构建复杂的请求体,与HTML文件上传形式兼容。多块请求体中每块请求都是一个请求体,可以定义自己的请求头。这些请求头可以用来描述这块请求,例如他的 Content-Disposition 。如果 Content-Length 和 Content-Type 可用的话,他们会被自动添加到请求头中。
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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