Is there a way, using the below Java code, to convert HashMap into JSON? I have

ID: 3748011 • Letter: I

Question

Is there a way, using the below Java code, to convert HashMap into JSON? I have tried to figure this out but I'm not familiar with using JSON and I don't know how to do it.

//Response Header Imports
import java.net.URL;
import java.net.URLConnection;
import java.util.List;
import java.util.Map;
import java.io.IOException;
import java.net.MalformedURLException;
/////////////////////////////////
import org.apache.catalina.Server;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.servlet.ModelAndView;

import java.util.HashMap;
import java.util.Map;

import java.net.URL;
import javax.net.ssl.HttpsURLConnection;
import java.security.cert.Certificate;
import javax.net.ssl.SSLPeerUnverifiedException;
import java.net.MalformedURLException;
import java.io.IOException;

public class ServerAnalyzerBackEnd {

private String url;

    public ServerAnalyzerBackEnd(String url) {
        this.url = url;
    }

    public ModelAndView start() {
        Map<String, Object> params = new HashMap<>();
        params.put("url", url);
        String secureURL = "";
        URL testURL;

        //url is not null, assign to secureURL to create https connection
        if(url != null){
            secureURL = url;
        }

//Initialize Strings for later output
String response_header = "";

        //create URL object from 'url'
        //create https connection based off of url and then call getCertChain method to pull that cert chain
        try {
            testURL = new URL(secureURL);
            HttpsURLConnection connection = (HttpsURLConnection)testURL.openConnection();
            getCertChain(connection);
            response_header = getResponseHeader(connection);
        }
        catch(MalformedURLException e){
            e.printStackTrace();
        }
        catch(IOException e){
            e.printStackTrace();
        }

//Put strings into Hash Map to be displayed in output
params.put("response_header", response_header);

return new ModelAndView("showURL", params);
}

    public void getCertChain(HttpsURLConnection connection){
        if(connection != null){
            try{
                //this initiates handshake, to ssl server without it, handshake will not occur and 500 error will be thrown
                connection.getInputStream();

//make array of Certificate objects and grab the cert chain from the https connection
Certificate[] certificates = connection.getServerCertificates();

                //foreach c in Certificates print cert details to console.
                for(Certificate c : certificates){
                    System.out.println("cert type: " + c.getType());
                    System.out.println("cert PK Algorithm: " + c.getPublicKey().getAlgorithm());
                    System.out.println("cert PK Format: " + c.getPublicKey().getFormat());
                    System.out.println();
                }
            }
            catch (SSLPeerUnverifiedException e){
                e.printStackTrace();
            }
            catch (IOException e){
                e.printStackTrace();
            }

}
}

public String getResponseHeader(HttpsURLConnection connection){
String result = "Key 'Content-Type' is not found!";

        //Response Header Function
        try {
            System.out.println("HTTP Headers");
            System.out.println();

            Map<String, List<String>> map = connection.getHeaderFields();
            for (Map.Entry<String, List<String>> entry : map.entrySet()) {
                System.out.println(entry.getKey() + ": " + entry.getValue());
            }
            System.out.println();
            System.out.println("Get Header by key:");
            String server = connection.getHeaderField("Content-Type");

            if (server != null) {
                result = "Content-Type: " + server;
            }

        } catch (Exception e) {
            e.printStackTrace();
        }

        System.out.println(result);
        return result;
    }

}

Explanation / Answer

Program:

import java.net.URL;

import java.util.List;

import java.util.Map;

import java.io.IOException;

import java.net.MalformedURLException;

import org.json.JSONObject;

import org.springframework.web.servlet.ModelAndView;

import com.fasterxml.jackson.core.JsonGenerator;

import com.fasterxml.jackson.core.JsonProcessingException;

import com.fasterxml.jackson.databind.ObjectMapper;

import java.util.HashMap;

import javax.net.ssl.HttpsURLConnection;

import java.security.cert.Certificate;

import javax.net.ssl.SSLPeerUnverifiedException;

public class ServerAnalyzerBackEnd {

private String url;

public ServerAnalyzerBackEnd(String url) {

this.url = url;

}

public ModelAndView start() {

Map<String, Object> params = new HashMap<>();

params.put("url", url);

String secureURL = "";

URL testURL;

//url is not null, assign to secureURL to create https connection

if(url != null){

secureURL = url;

}

//Initialize Strings for later output

String response_header = "";

//create URL object from 'url'

//create https connection based off of url and then call getCertChain method to pull that cert chain

try {

testURL = new URL(secureURL);

HttpsURLConnection connection = (HttpsURLConnection)testURL.openConnection();

getCertChain(connection);

response_header = getResponseHeader(connection);

}

catch(MalformedURLException e){

e.printStackTrace();

}

catch(IOException e){

e.printStackTrace();

}

//Put strings into Hash Map to be displayed in output

params.put("response_header", response_header);

//there many ways to return JSON object in that this is one way

ObjectMapper mapperObj = new ObjectMapper();

String json="";

try {

json = mapperObj.writeValueAsString(params);

} catch (JsonProcessingException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

//Adding View name while creating ModelAndView object

ModelAndView mav=new ModelAndView("showURL");

mav.addObject(json); //Adding an JSON object

return mav;

// return new ModelAndView("showURL",json);

}

public void getCertChain(HttpsURLConnection connection){

if(connection != null){

try{

//this initiates handshake, to ssl server without it, handshake will not occur and 500 error will be thrown

connection.getInputStream();

//make array of Certificate objects and grab the cert chain from the https connection

Certificate[] certificates = connection.getServerCertificates();

//foreach c in Certificates print cert details to console.

for(Certificate c : certificates){

System.out.println("cert type: " + c.getType());

System.out.println("cert PK Algorithm: " + c.getPublicKey().getAlgorithm());

System.out.println("cert PK Format: " + c.getPublicKey().getFormat());

System.out.println();

}

catch (SSLPeerUnverifiedException e){

e.printStackTrace();

}

catch (IOException e){

e.printStackTrace();

}

public String getResponseHeader(HttpsURLConnection connection){

String result = "Key 'Content-Type' is not found!";

//Response Header Function

try {

System.out.println("HTTP Headers");

System.out.println();

Map<String, List<String>> map = connection.getHeaderFields();

for (Map.Entry<String, List<String>> entry : map.entrySet()) {

System.out.println(entry.getKey() + ": " + entry.getValue());

}

System.out.println();

System.out.println("Get Header by key:");

String server = connection.getHeaderField("Content-Type");

if (server != null) {

result = "Content-Type: " + server;

}

} catch (Exception e) {

e.printStackTrace();

}

System.out.println(result);

return result;

}

Output:

cert type: X.509
cert PK Algorithm: EC
cert PK Format: X.509

cert type: X.509
cert PK Algorithm: RSA
cert PK Format: X.509

HTTP Headers

Transfer-Encoding: [chunked]
null: [HTTP/1.1 200 OK]
Alt-Svc: [quic=":443"; ma=2592000; v="44,43,39,35"]
Server: [gws]
P3P: [CP="This is not a P3P policy! See g.co/p3phelp for more info."]
Date: [Sat, 15 Sep 2018 21:34:23 GMT]
Accept-Ranges: [none]
X-Frame-Options: [SAMEORIGIN]
Cache-Control: [private, max-age=0]
Vary: [Accept-Encoding]
Set-Cookie: [NID=139=gWqo_-1bPJJvrm2SnY4vVwPd5SI7dKkqcZAuXq8JLOdpMNT6JdkMiqtG3DWk8a02YN2bgB5Dwb5Nee3yYCARH0TI_p6Z4Ecy9_J5E5DIskxXyFHa2osvnKx4cpXZsgY1; expires=Sun, 17-Mar-2019 21:34:23 GMT; path=/; domain=.google.co.in; HttpOnly, 1P_JAR=2018-09-15-21; expires=Mon, 15-Oct-2018 21:34:23 GMT; path=/; domain=.google.co.in]
Expires: [-1]
X-XSS-Protection: [1; mode=block]
Content-Type: [text/html; charset=UTF-8]

Get Header by key:
Content-Type: text/html; charset=UTF-8

Your Model Content AS JSON:

print Model : {string={"response_header":"Content-Type: text/html; charset=UTF-8","url":"https://www.google.co.in/maps/@13.0000588,78.1647889,15z"}}

Here don't mistake "{string=" is added reason is since I have converted Json to String using ObjectMapper and we are returning the Model instead of object, model will always returns an "DataType of an object"(String) & "Value of an object"({"response_header":"Content-Type: text/html; charset=UTF-8","url":"https://www.google.co.in/maps/@13.0000588,78.1647889,15z"}).

print View : showURL

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