Bael 6188: Extract CN from X509Certificate in Java (#14681)

* #BAEL-6188:add unit tests * #BAEL-6188:add dependencies * #BAEL-6188:add certificate * #BAEL-6188:add extract CN using Regex * #BAEL-6188:refactor CN using Regex * #BAEL-6188:refactor test case name * #BAEL-6188:add properties for dependency version
2023-09-10 22:41:22 +03:30
parent 53f3cf70a1
commit d2a1340d5c
3 changed files with 132 additions and 0 deletions
@@ -0,0 +1,94 @@
+package com.baeldung.certificate;
+
+import org.bouncycastle.asn1.x500.RDN;
+import org.bouncycastle.asn1.x500.X500Name;
+import org.bouncycastle.asn1.x500.style.BCStyle;
+import org.bouncycastle.asn1.x500.style.IETFUtils;
+import org.bouncycastle.jce.provider.BouncyCastleProvider;
+import org.cryptacular.util.CertUtil;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import javax.naming.ldap.LdapName;
+import javax.naming.ldap.Rdn;
+import javax.security.auth.x500.X500Principal;
+import java.io.FileInputStream;
+import java.security.Security;
+import java.security.cert.CertificateFactory;
+import java.security.cert.X509Certificate;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class ExtractCommonNameUnitTest {
+
+    private static final String EXPECTED_CN = "Baeldung";
+
+    private String certificatePath = "src/main/resources/Baeldung.cer";
+
+    private X509Certificate certificate;
+
+    @BeforeEach
+    public void setUp() throws Exception {
+        Security.addProvider(new BouncyCastleProvider());
+        CertificateFactory certificateFactory = CertificateFactory.getInstance("X.509", "BC");
+        certificate = (X509Certificate) certificateFactory.generateCertificate(new FileInputStream(certificatePath));
+    }
+
+    @Test
+    void whenUsingBouncyCastle_thenExtractCommonName() {
+        X500Principal principal = certificate.getSubjectX500Principal();
+        X500Name x500Name = new X500Name(principal.getName());
+        RDN[] rdns = x500Name.getRDNs(BCStyle.CN);
+        List<String> names = new ArrayList<>();
+        for (RDN rdn : rdns) {
+            String name = IETFUtils.valueToString(rdn.getFirst().getValue());
+            names.add(name);
+        }
+
+        for (String commonName : names) {
+            assertEquals(EXPECTED_CN, commonName);
+        }
+    }
+
+    @Test
+    void whenUsingLDAPAPI_thenExtractCommonName() throws Exception {
+        X500Principal principal = certificate.getSubjectX500Principal();
+        LdapName ldapDN = new LdapName(principal.getName());
+        List<String> names = new ArrayList<>();
+        for (Rdn rdn : ldapDN.getRdns()) {
+            if (rdn.getType().equalsIgnoreCase("cn")) {
+                String name = rdn.getValue().toString();
+                names.add(name);
+            }
+        }
+
+        for (String commonName : names) {
+            assertEquals(EXPECTED_CN, commonName);
+        }
+    }
+
+    @Test
+    void whenUsingCryptacular_thenExtractCommonName() {
+        String commonName = CertUtil.subjectCN(certificate);
+        assertEquals(EXPECTED_CN, commonName);
+    }
+
+    @Test
+    void whenUsingRegex_thenExtractCommonName() {
+        X500Principal principal = certificate.getSubjectX500Principal();
+        List<String> names = new ArrayList<>();
+        Pattern pattern = Pattern.compile("CN=([^,]+)");
+        Matcher matcher = pattern.matcher(principal.getName());
+        while (matcher.find()) {
+            names.add(matcher.group(1));
+        }
+
+        for (String commonName : names) {
+            assertEquals(EXPECTED_CN, commonName);
+        }
+    }
+}