不可变的成员变量增加 final 修饰符

Author: Eric-Lee-Handyman

src/main/java/com/wechat/pay/contrib/apache/httpclient/auth/PrivateKeySigner.java

@@ -9,8 +9,8 @@
 
 public class PrivateKeySigner implements Signer {
 
-    protected String certificateSerialNumber;
-    protected PrivateKey privateKey;
+    protected final String certificateSerialNumber;
+    protected final PrivateKey privateKey;
 
     public PrivateKeySigner(String serialNumber, PrivateKey privateKey) {
         this.certificateSerialNumber = serialNumber;

src/main/java/com/wechat/pay/contrib/apache/httpclient/auth/Signer.java

@@ -6,8 +6,8 @@ public interface Signer {
 
     class SignatureResult {
 
-        protected String sign;
-        protected String certificateSerialNumber;
+        protected final String sign;
+        protected final String certificateSerialNumber;
 
         public SignatureResult(String sign, String serialNumber) {
             this.sign = sign;

src/main/java/com/wechat/pay/contrib/apache/httpclient/auth/WechatPay2Credentials.java

@@ -18,8 +18,8 @@ public class WechatPay2Credentials implements Credentials {
 
     protected static final String SYMBOLS = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
     protected static final SecureRandom RANDOM = new SecureRandom();
-    protected String merchantId;
-    protected Signer signer;
+    protected final String merchantId;
+    protected final Signer signer;
 
     public WechatPay2Credentials(String merchantId, Signer signer) {
         this.merchantId = merchantId;

src/main/java/com/wechat/pay/contrib/apache/httpclient/auth/WechatPay2Validator.java

@@ -22,7 +22,7 @@ public class WechatPay2Validator implements Validator {
 
     protected static final Logger log = LoggerFactory.getLogger(WechatPay2Validator.class);
 
-    protected Verifier verifier;
+    protected final Verifier verifier;
 
     public WechatPay2Validator(Verifier verifier) {
         this.verifier = verifier;