HTTP GET/POST Example

Following example can be used to send HTTP GET or POST request to web server using JAVA application.

// HTTP GET request
private void sendGet() throws Exception {

String url = "http://seguide.blogspot.com";

HttpClient client = new DefaultHttpClient();
HttpGet request = new HttpGet(url);

request.addHeader("User-Agent", USER_AGENT);

HttpResponse response = client.execute(request);

System.out.println("\nSending 'GET' request to URL : " + url);
System.out.println("Response Code : " + 
                       response.getStatusLine().getStatusCode());

BufferedReader rd = new BufferedReader(
                       new InputStreamReader(response.getEntity().getContent()));

StringBuffer result = new StringBuffer();
String line = "";
while ((line = rd.readLine()) != null) {
result.append(line);
}

System.out.println(result.toString());

}

// HTTP POST request
private void sendPost() throws Exception {

String url = "http://seguide.blogspot.com";

HttpClient client = new DefaultHttpClient();
HttpPost post = new HttpPost(url);

post.setHeader("User-Agent", USER_AGENT);

List urlParameters = new ArrayList();
urlParameters.add(new BasicNameValuePair("name", "sujith"));
urlParameters.add(new BasicNameValuePair("pass", "abc123"));
urlParameters.add(new BasicNameValuePair("param1", "param1"));
urlParameters.add(new BasicNameValuePair("param2", "param2"));

post.setEntity(new UrlEncodedFormEntity(urlParameters));

HttpResponse response = client.execute(post);
System.out.println("\nSending 'POST' request to URL : " + url);
System.out.println("Post parameters : " + post.getEntity());
System.out.println("Response Code : " + 
                                    response.getStatusLine().getStatusCode());

BufferedReader rd = new BufferedReader(
                        new InputStreamReader(response.getEntity().getContent()));

StringBuffer result = new StringBuffer();
String line = "";
while ((line = rd.readLine()) != null) {
result.append(line);
}

System.out.println(result.toString());

}

Change permission for user in Linux

Following set of commands can be used to change the permission of a user.

Change directory

           sujithde@ewaps1:~> cd delight/

Change permission for user oracle

           sujithde@ewaps1:~/delight> setfacl –R -m user:oracle:rwx .

Add user a mask

           sujithde@ewaps1:~/delight> setfacl –R -m mask:rwx .

Note : –R will recursively change permission for sub folders. 

Run SQL script in Background in MySQL server

Following command can be used to run SQL script in background in MySQL server.

mysql --user=sujith --pass=123suji --database=postdb --host=localhost script_file results.out &

This will return output of script  to result.out file.

JAVA 8 Lambda Expression

Following example explain how Lambda Expression can be implemented in JAVA 8.

    interface MathOperation {

        int execute(int a, int b);

    }

    public int calculate(int a, int b, MathOperation op) {

        return op.execute(a, b);

    }

    public static void main(String[] args) {

        Lamda lamda = new Lamda();

        MathOperation addition = (a, b) -> (a + b);

        MathOperation substract = (a, b) -> (a - b);

        System.out.println(lamda.calculate(4, 5, addition));

        System.out.println(lamda.calculate(4, 5, substract));

    }