Apacheのhttpclientを利用してServiceNow REST API（ Table API）をJavaでたたく方法

前記事

ここではJavaのプレーンなものでGETを実行しました。

Apacheのhttpclientを利用してGETを実行

import java.io.*;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.util.Base64;

import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.HttpClientBuilder;

public class App {

    public static void main(String[] args) throws ClientProtocolException, IOException {
        getMethodByApache();
    }

    private static void getMethodByApache() throws ClientProtocolException, IOException {
        // ユーザーIDやパスワードは適切なものに書き換えてください
        String user = "admin";
        String pass = "xxxx";
        // URLは適切なものに書き換えてください
        String url = "https://xxxxxxx.service-now.com/api/now/table/incident?sysparm_limit=1";

        HttpGet request = new HttpGet(url);
        request.addHeader("Content-Type", "application/json");
        request.addHeader("Accept", "application/json");
        request.addHeader("user", user
                + ":"
                + pass);
        String authString = getAuthorizationString(user, pass);
        request.addHeader("Authorization", "Basic "
                + authString);
        HttpClient client = HttpClientBuilder.create().build();
        HttpResponse response = client.execute(request);
        int httpStatusCode = response.getStatusLine().getStatusCode();
        if (httpStatusCode == 200) {
            BufferedReader br = new BufferedReader(new InputStreamReader((response.getEntity().getContent())));
            String output;
            while ((output = br.readLine()) != null) {
                System.out.println(output);
            }
        }
    }

    private static String getAuthorizationString(String user, String password) {
        Charset charset = StandardCharsets.UTF_8;
        String userPassword = user
                + ":"
                + password;
        //byte[] authEncodedBytes = Base64.encodeBase64(userPassword.getBytes());
        byte[] authEncodedBytes = Base64.getEncoder().encode(userPassword.getBytes(charset));
        String authString = new String(authEncodedBytes);
        return authString;
    }

}

pom.xmlについて

Mavenを使っていたのでライブラリはpom.xmlで既存のものに対して以下のように追記した。

        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
            <version>4.5.13</version>
        </dependency>