cURL和HttpURLConnection - 发布JSON数据

Question

如何使用HttpURLConnection发布JSON数据？我想这一点：

HttpURLConnection httpcon = (HttpURLConnection) ((new URL("a url").openConnection())); 
httpcon.setDoOutput(true); 
httpcon.setRequestProperty("Content-Type", "application/json"); 
httpcon.setRequestProperty("Accept", "application/json"); 
httpcon.setRequestMethod("POST"); 
httpcon.connect(); 

StringReader reader = new StringReader("{'value': 7.5}"); 
OutputStream os = httpcon.getOutputStream(); 

char[] buffer = new char[4096]; 
int bytes_read;  
while((bytes_read = reader.read(buffer)) != -1) { 
    os.write(buffer, 0, bytes_read);// I am getting compilation error here 
} 
os.close(); 

我得到的编译错误在第14行

卷曲请求：

curl -H "Accept: application/json" \ 
-H "Content-Type: application/json" \ 
-d "{'value': 7.5}" \ 
"a URL" 

这是处理卷曲请求的方式？任何信息对我都很有帮助。

谢谢。

Answer 1

OutputStream期望与字节一起使用，并且您将字符传递给它。试试这个：

HttpURLConnection httpcon = (HttpURLConnection) ((new URL("a url").openConnection())); 
httpcon.setDoOutput(true); 
httpcon.setRequestProperty("Content-Type", "application/json"); 
httpcon.setRequestProperty("Accept", "application/json"); 
httpcon.setRequestMethod("POST"); 
httpcon.connect(); 

byte[] outputBytes = "{'value': 7.5}".getBytes("UTF-8"); 
OutputStream os = httpcon.getOutputStream(); 
os.write(outputBytes); 

os.close(); 

Answer 2

您可能需要使用OutputStreamWriter类。

final String toWriteOut = "{'value': 7.5}"; 
final OutputStreamWriter osw = new OutputStreamWriter(connection.getOutputStream()); 
osw.write(toWriteOut); 
osw.close();