Question

我对Java很新，但是当使用带有HttpUrlConnection的POST请求的OutputStreamWriter和DataOutputStream时，我有不同的结果。

我可以在使用DataOutputStream时附加参数。

URL url = new URL("https://www.google-analytics.com/debug/collect");
HttpURLConnection conn = (HttpURLConnection) url.openConnection();

conn.setDoOutput(true);
conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded;");
conn.setRequestMethod("POST");

String parameters = "v=1&tid=UA-62749954-12&cid=test.clientid.456&t=event&ec=offline_cv&ea=register";

DataOutputStream writer = new DataOutputStream(conn.getOutputStream());
writer.writeBytes(parameters);

writer.close();
conn.connect();

响应：

{  "hitParsingResult": [ {    "valid": true,    "parserMessage": [ ],    "hit": "/debug/collect?v=1\u0026tid=UA-62749954-12\u0026cid=test.clientid.456\u0026t=event\u0026ec=offline_cv\u0026ea=register"  } ],  "parserMessage": [ {    "messageType": "INFO",    "description": "Found 1 hit in the request."  } ]}

但是，使用OutputStreamWriter时无法附加参数。

OutputStreamWriter writer = new OutputStreamWriter(conn.getOutputStream());
writer.write(URLEncoder.encode(parameters, "UTF-8"));

响应：

{  "hitParsingResult": [ {    "valid": false,    "parserMessage": [ {      "messageType": "ERROR",      "description": "A value is required for parameter 'v'. Please see https://developers.google.com/analytics/devguides/collection/protocol/v1/parameters#v for details.",      "messageCode": "VALUE_REQUIRED",      "parameter": "v"    } ],    "hit": "/debug/collect"  } ],  "parserMessage": [ {    "messageType": "INFO",    "description": "Found 1 hit in the request."  } ]}

是因为DataOutputStream与String兼容，而OutputStreamWriter不兼容吗？

Answer 1

1）问题在于：

URLEncoder.encode(parameters, "UTF-8")

您的参数已经过网址编码。调用此方法会使它们格式不正确。

2）使用一些工具来监控HTTP请求，以了解请求和响应会发生什么。

DataOutputStream和OutputStreamWriter之间的区别：字符串兼容性？

1 个答案: