feat(crypto): optimize the code

Author: Federico2014

chainbase/src/main/java/org/tron/common/utils/LocalWitnesses.java

@@ -46,7 +46,7 @@ public LocalWitnesses(List<String> privateKeys) {
   }
 
   public byte[] getWitnessAccountAddress(boolean isECKeyCryptoEngine) {
-    if (witnessAccountAddress == null && !this.privateKeys.isEmpty()) {
+    if (witnessAccountAddress == null && !CollectionUtils.isEmpty(privateKeys)) {
       byte[] privateKey = ByteArray.fromHexString(getPrivateKey());
       final SignInterface cryptoEngine = SignUtils.fromPrivate(privateKey, isECKeyCryptoEngine);
       this.witnessAccountAddress = cryptoEngine.getAddress();
@@ -59,7 +59,7 @@ public void setWitnessAccountAddress(final byte[] localWitnessAccountAddress) {
   }
 
   public void initWitnessAccountAddress(boolean isECKeyCryptoEngine) {
-    if (witnessAccountAddress == null && !this.privateKeys.isEmpty()) {
+    if (witnessAccountAddress == null && !CollectionUtils.isEmpty(privateKeys)) {
       byte[] privateKey = ByteArray.fromHexString(getPrivateKey());
       final SignInterface ecKey = SignUtils.fromPrivate(privateKey,
           isECKeyCryptoEngine);

crypto/src/main/java/org/tron/common/crypto/ECKey.java

@@ -285,7 +285,7 @@ public static ECKey fromPrivate(BigInteger privKey) {
    * @return -
    */
   public static ECKey fromPrivate(byte[] privKeyBytes) {
-    if (Objects.isNull(privKeyBytes) || privKeyBytes.length == 0) {
+    if (ByteUtil.isNullOrZeroArray(privKeyBytes)) {
       return null;
     }
     return fromPrivate(new BigInteger(1, privKeyBytes));

crypto/src/main/java/org/tron/common/crypto/sm2/SM2.java

@@ -247,7 +247,7 @@ public static SM2 fromPrivate(BigInteger privKey) {
    * @return -
    */
   public static SM2 fromPrivate(byte[] privKeyBytes) {
-    if (Objects.isNull(privKeyBytes) || privKeyBytes.length == 0) {
+    if (ByteUtil.isNullOrZeroArray(privKeyBytes)) {
       return null;
     }
     return fromPrivate(new BigInteger(1, privKeyBytes));

framework/src/main/java/org/tron/core/metrics/node/NodeMetricManager.java

@@ -5,6 +5,7 @@
 import org.springframework.stereotype.Component;
 import org.tron.common.backup.BackupManager;
 import org.tron.common.parameter.CommonParameter;
+import org.tron.common.utils.ByteUtil;
 import org.tron.core.ChainBaseManager;
 import org.tron.core.config.args.Args;
 import org.tron.program.Version;
@@ -38,8 +39,8 @@ private void setNodeInfo(NodeInfo nodeInfo) {
 
     byte[] witnessAccountAddress = Args.getLocalWitnesses()
         .getWitnessAccountAddress(CommonParameter.getInstance().isECKeyCryptoEngine());
-    ByteString witnessAddress =
-        witnessAccountAddress != null ? ByteString.copyFrom(witnessAccountAddress) : null;
+    ByteString witnessAddress = !ByteUtil.isNullOrZeroArray(witnessAccountAddress) ? ByteString
+        .copyFrom(witnessAccountAddress) : null;
     if (chainBaseManager.getWitnessScheduleStore().getActiveWitnesses().contains(witnessAddress)) {
       nodeInfo.setNodeType(1);
     } else {