Java 使用 HttpURLConnection 提交 json POST 请求
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Using HttpURLConnection to submit a json POST request
提问by Austin
I am trying to submit a json post request using HttpURLConnection in Scala. I followed along to two tutorials and produced this:
我正在尝试使用 Scala 中的 HttpURLConnection 提交一个 json post 请求。我跟着两个教程制作了这个：
def sendPost(url: String, jsonHash: String) {
val conn: HttpURLConnection = new URL(url).openConnection().asInstanceOf[HttpURLConnection]
conn.setRequestMethod("POST")
conn.setRequestProperty("Content-Type", "application/json")
conn.setRequestProperty("Accept", "application/json")
conn.setDoOutput(true)
conn.connect()
val wr = new DataOutputStream(conn.getOutputStream)
wr.writeBytes(jsonHash)
wr.flush()
wr.close()
val responseCode = conn.getResponseCode
println("Sent: " + jsonHash + " to " + url + " received " + responseCode)
val in = new BufferedReader(new InputStreamReader(conn.getInputStream))
var response: String = ""
while(response != null) {
response = in.readLine()
println(response)
}
in.close()
}
It responds with:
它回应：
Sent: '{"schedule":"R/2014-02-02T00:00:00Z/PT24H", "name":"Scala-Post-Test", "command":"which scalac", "epsilon":"PT15M", "owner":"[email protected]", "async":false}' to http://localhost:4040/scheduler/iso8601 received 500
java.io.IOException: Server returned HTTP response code: 500 for URL: http://localhost:4040/scheduler/iso8601
stemming from
源于
val in = new BufferedReader(new InputStreamReader(conn.getInputStream))
but if I rebuild it as a curlrequest, it works fine:
但如果我根据curl请求重建它，它工作正常：
curl -X POST -H 'Content-Type: application/json' -d '{"schedule":"R/2014-02-02T00:00:00Z/PT24H", "name":"Scala-Post-Test", "command":"which scalac", "epsilon":"PT15M", "owner":"[email protected]", "async":false}' http://localhost:4040/scheduler/iso8601
requirement failed: Vertex already exists in graph Scala-Post-Test
(which is what I expect)
（这是我所期望的）
Any insight to what is wrong? I'm trying to sniff the packets now to determine what is different.
对什么是错的任何见解？我现在试图嗅探数据包以确定有什么不同。
(Note: I had previously given up on sys.process._)
（注意：我之前已经放弃了sys.process._）
采纳答案by Brian Roach
The issue is here:
问题在这里：
Sent: '{"schedule":"R/2014-02-02T00:00:00Z/PT24H", "name":"Scala-Post-Test", "command":"which scalac", "epsilon":"PT15M", "owner":"[email protected]", "async":false}' to http://localhost:4040/scheduler/iso8601 received 500
You'll note your JSON is surrounded by single quotes. This makes it invalid.
您会注意到您的 JSON 被单引号包围。这使它无效。
Also worth noting is that while this code works, you are using a DataOutputStream.writeBytes()to output your data. This would be problematic if your string including anything but single-byte characters; it strips the high 8 bits off each char(Java uses 2-byte chars to hold UTF-16 codepoints).
另外值得注意的是，虽然此代码有效，但您正在使用 aDataOutputStream.writeBytes()来输出您的数据。如果您的字符串包含除单字节字符以外的任何内容，这将是有问题的；它每个去掉高 8 位char（Java 使用 2 字节字符来保存 UTF-16 代码点）。
It's better to use something more suited for Stringoutput. The same technique you use for input, for example:
最好使用更适合String输出的东西。用于输入的相同技术，例如：
BufferedWriter out =
new BufferedWriter(new OutputStreamWriter(conn.getOutputStream));
out.write(jsonString);
out.close();
