java无法从URLConnection获取JSON响应
我正在尝试使用JavaURLConnection读取来自googleapi的响应
在浏览器中,如果我查询 “https://www.googleapis.com/pagespeedonline/v2/runPagespeed?url=https%3A%2F%2Fwww.zauq.se&strategy=mobilez”
我得到JSON格式的响应
{
"error": {
"errors": [
{
"domain": "global",
"reason": "invalidParameter",
"message": "Invalid string value: 'mobilez'. Allowed values: [desktop, mobile]",
"locationType": "parameter",
"location": "strategy"
}
],
"code": 400,
"message": "Invalid string value: 'mobilez'. Allowed values: [desktop, mobile]"
}
}
但是当我使用下面的代码时
URL url = null;
System.setProperty("http.agent", "");
url = new URL("https://www.googleapis.com/pagespeedonline/v2/runPagespeed?url=https%3A%2F%2Fwww.zauq.se&strategy=mobilez");//"https://www.googleapis.com/pagespeedonline/v2/runPagespeed?url=" + paramUrl + "&strategy=" + paramStrategy);
URLConnection conn = url.openConnection();
conn.setRequestProperty("Accept", "application/json");
conn.setRequestProperty("User-Agent", "Mozilla/5.0");
BufferedReader br = new BufferedReader(new InputStreamReader(conn.getInputStream()));
String strTemp = "";
StringBuilder sb = new StringBuilder();
while ((null != (strTemp = br.readLine())))
{
sb.append(strTemp);
if (dump)
{
System.out.println(strTemp);
}
}
我得到IO异常
java.io.IOException: Server returned HTTP response code: 400 for URL: https://www.googleapis.com/pagespeedonline/v2/runPagespeed?url=https%3A%2F%2Fwww.zauq.se&strategy=mobilez
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1627)
at sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:254)
at amirTest.PageSpeedCheck.main(PageSpeedCheck.java:62)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:144)
/但我需要得到JSON响应
请告诉我需要做什么更改才能得到JSON作为响应
# 1 楼答案
谢谢@JB Nizet
它在我尝试读取错误流时起作用
# 2 楼答案
将连接强制转换为Http(s)URLConnection,并在出现错误时调用getErrorStream()以获取流
# 3 楼答案
API调用中使用的参数错误,因此服务器正在重新运行状态代码400。这意味着这是一个错误的要求
mobilz应该是移动的。此外,您使用的url不正确
# 4 楼答案
您只需按以下方式更改代码:
见原始答案here
参见以下类似的SO问题:
URLConnection Error - java.io.IOException: Server returned HTTP response code: 400 for URL
Server returned HTTP response code: 400
# 5 楼答案
对于:400:
您正在以移动z而不是移动发送策略
改变
https://www.googleapis.com/pagespeedonline/v2/runPagespeed?url=https%3A%2F%2Fwww.zauq.se&strategy=mobilez
到
https://www.googleapis.com/pagespeedonline/v2/runPagespeed?url=https%3A%2F%2Fwww.zauq.se&strategy=mobile
请注意URL末尾的z
获取JSON响应:
参考:How to Parse this JSON Response in JAVA