okhttp學習-------post方式實作

在項目應用中常見的http請求方式主要有get,post兩種請求方式，常用post方式又有四種不同方式HTTP常用post請求方式，okhttp對post 方式提供了很好的支援。

在okhttp中，http封包體抽象為RequestBody類，RequestBody既是各類封包body的基類，又是其工廠類，提供了重載的create用于建立RequestBody對象，相關類圖如下

對于postbody為Json資料的請求可以直接使用RequestBody的create 方法。

FormBody實作

private long writeOrCountBytes(BufferedSink sink, boolean countBytes) {
    long byteCount = L;

    Buffer buffer;
    if (countBytes) {
      buffer = new Buffer();
    } else {
      buffer = sink.buffer();
    }
    ／／向緩沖區寫入key和value值：遵循格式key1=value1&key2＝value2...
    for (int i = , size = encodedNames.size(); i < size; i++) {
      if (i > ) buffer.writeByte('&');
      buffer.writeUtf8(encodedNames.get(i));
      buffer.writeByte('=');
      buffer.writeUtf8(encodedValues.get(i));
    }
    if (countBytes) {
      byteCount = buffer.size();
      buffer.clear();
    }
    return byteCount;
  }
           

2.MultiPartBody實作代碼（參考表單送出的格式定義）

private long writeOrCountBytes(BufferedSink sink, boolean countBytes) throws IOException {
    long byteCount = ;
    Buffer byteCountBuffer = null;
    if (countBytes) {
      sink = byteCountBuffer = new Buffer();
    }
／／循環寫入part到緩沖區
    for (int p = , partCount = parts.size(); p < partCount; p++) {
      Part part = parts.get(p);
      Headers headers = part.headers;
      RequestBody body = part.body;

      sink.write(DASHDASH);／／{':', ' '}
      sink.write(boundary);／／part分割标記
      sink.write(CRLF);／／換行\r\n
      if (headers != null) {
        for (int h = , headerCount = headers.size(); h < headerCount; h++) {
          sink.writeUtf8(headers.name(h))
              .write(COLONSPACE)／／{':', ' '}
              .writeUtf8(headers.value(h))
              .write(CRLF);
        }
      }
      MediaType contentType = body.contentType();
      if (contentType != null) {
        sink.writeUtf8("Content-Type: ")
            .writeUtf8(contentType.toString())
            .write(CRLF);
      }
      long contentLength = body.contentLength();
      if (contentLength != -) {
        sink.writeUtf8("Content-Length: ")
            .writeDecimalLong(contentLength)
            .write(CRLF);
      } else if (countBytes) {
        // We can't measure the body's size without the sizes of its components.
        byteCountBuffer.clear();
        return -;
      }

      sink.write(CRLF);

      if (countBytes) {
        byteCount += contentLength;
      } else {
        body.writeTo(sink);
      }
      sink.write(CRLF);
    }

    sink.write(DASHDASH);
    sink.write(boundary);
    sink.write(DASHDASH);
    sink.write(CRLF);
    if (countBytes) {
      byteCount += byteCountBuffer.size();
      byteCountBuffer.clear();
    }
    return byteCount;
  }
           

3.建立Json格式的RequestBody對象

JSONbject json= createJson();
RequestBody body=RequestBody.create(MediaType.parse("application/json"),json.toJsonString)；