HttpConnection Class
The HttpConnection class makes a HTTP connection to a given URI. You can use it to make GET and POST requests to other web services.
HTTPS calls are supported only for URIs that have standard security certificates.
When you call the execute method in HttpConnection, it executes the request, gets the response, and closes the connection. This means that a single object cannot be used multiple times. For multiple HTTP requests, instantiate multiple instances.
Note: Make sure that the URL is properly encoded when instantiating an HttpConnection object.
Constructor
You create an instance of HttpConnection using the new operator.
- Method signature
HttpConnection con = new HttpConnection(int methodType, String URI)
- methodType
- Sets the HTTP method type:
- CONSTANTS.HTTP.METHOD.GET for HTTP GET requests
- CONSTANTS.HTTP.METHOD.POST for HTTP POST requests
- String URI
- URI to which to connect
Methods
The methods are:
addHeader
Adds a key-value pair to the request header.
- Method signature
void addHeader(String key, String value)
- Parameters
- key - The name of the key
- value - The value of the key
- Return
- None
addParameter
Adds a parameter to an HTTP POST request. This methods throws an exception if it is called for an HTTP GET request.
- Method signature
void addParameter(String key, String value)
- Parameters
- key - The name of the key
- value - The value of the key
- Return
- None
execute
Executes the request and returns a standard HTTP response such as "200 - OK" or "404 - not found".
- Method signature
int execute()
- Parameters
- None
- Return
- Standard HTTP response
getResponse
Returns the response as a String.
- Method signature
String getResponse()
- Parameters
- None
- Return
- The response from the service
encode
Returns a String encoded from s.
- Method signature
String encode(String s)
- Parameters
-
- s - The string to encode
- Return
- The encoded string
getResponseHeaders
Retrieve the headers from the HTTP Response from an external server. It is a map of String Header Name/Header Value pairs.
For example, if the Header Content-Length is equal to 10008, then "Content-Length" is the Header Name and "10008" is the Header Value.
This method is to be called after execute method of HttpConnection.
- Method signature
- HashMap<String name, String value> getResponseHeaders()
- Parameters
- None
- Return
- A HashMap of Header Name/Header Value string pairs
setRequestBody
Specify the body of the request, the content type, and character set.
- Method signature
- HashMap<String name, String value> getResponseHeaders()
- Parameters
-
- content-Type - String. One of the valid Mime types for the body of a request. For example: "application/xml".
- charSet - String. The character set used in the request. For example: "utf-8".
- Return
- None
- Learn more:
HttpConnection Example
This example gets the result of a Google search for "IT Leaders".
<syntaxhighlight lang="java" enclose="div"> HttpConnection con = new HttpConnection(CONSTANTS.HTTP.METHOD.GET,
"http://www.google.com/search?hl=en&q=IT+Leaders&btnG=Google+Search");
int code= con.execute(); String response = con.getResponse(); </syntaxhighlight >