diff --git a/weixin-java-common/src/main/java/me/chanjar/weixin/common/util/SignUtils.java b/weixin-java-common/src/main/java/me/chanjar/weixin/common/util/SignUtils.java
index 9ea33b123..fc3579d45 100644
--- a/weixin-java-common/src/main/java/me/chanjar/weixin/common/util/SignUtils.java
+++ b/weixin-java-common/src/main/java/me/chanjar/weixin/common/util/SignUtils.java
@@ -1,12 +1,14 @@
 package me.chanjar.weixin.common.util;
 
-import lombok.extern.slf4j.Slf4j;
-import org.apache.commons.codec.binary.Hex;
-
-import javax.crypto.Mac;
-import javax.crypto.spec.SecretKeySpec;
+import java.nio.charset.StandardCharsets;
 import java.security.InvalidKeyException;
 import java.security.NoSuchAlgorithmException;
+import javax.crypto.Mac;
+import javax.crypto.spec.SecretKeySpec;
+
+import org.apache.commons.codec.binary.Hex;
+
+import lombok.extern.slf4j.Slf4j;
 
 /**
  * <pre>
@@ -27,9 +29,9 @@ public class SignUtils {
   public static String createHmacSha256Sign(String message, String key) {
     try {
       Mac sha256 = Mac.getInstance("HmacSHA256");
-      SecretKeySpec secretKeySpec = new SecretKeySpec(key.getBytes(), "HmacSHA256");
+      SecretKeySpec secretKeySpec = new SecretKeySpec(key.getBytes(StandardCharsets.UTF_8), "HmacSHA256");
       sha256.init(secretKeySpec);
-      byte[] bytes = sha256.doFinal(message.getBytes());
+      byte[] bytes = sha256.doFinal(message.getBytes(StandardCharsets.UTF_8));
       return Hex.encodeHexString(bytes).toUpperCase();
     } catch (NoSuchAlgorithmException | InvalidKeyException e) {
       SignUtils.log.error(e.getMessage(), e);
diff --git a/weixin-java-common/src/main/java/me/chanjar/weixin/common/util/crypto/PKCS7Encoder.java b/weixin-java-common/src/main/java/me/chanjar/weixin/common/util/crypto/PKCS7Encoder.java
index 8ce94cbac..efe7867ba 100755
--- a/weixin-java-common/src/main/java/me/chanjar/weixin/common/util/crypto/PKCS7Encoder.java
+++ b/weixin-java-common/src/main/java/me/chanjar/weixin/common/util/crypto/PKCS7Encoder.java
@@ -1,22 +1,22 @@
-/**
+/*
  * 对公众平台发送给公众账号的消息加解密示例代码.
  *
  * @copyright Copyright (c) 1998-2014 Tencent Inc.
  */
 
-// ------------------------------------------------------------------------
-
 package me.chanjar.weixin.common.util.crypto;
 
 import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
 
 /**
- * 提供基于PKCS7算法的加解
+ * 提供基于PKCS7算法的加解.
+ *
+ * @author tencent
  */
 public class PKCS7Encoder {
-
-  private static final Charset CHARSET = Charset.forName("utf-8");
+  private static final Charset CHARSET = StandardCharsets.UTF_8;
   private static final int BLOCK_SIZE = 32;
 
   /**
@@ -28,20 +28,17 @@ public class PKCS7Encoder {
   public static byte[] encode(int count) {
     // 计算需要填充的位数
     int amountToPad = BLOCK_SIZE - (count % BLOCK_SIZE);
-    if (amountToPad == 0) {
-      amountToPad = BLOCK_SIZE;
-    }
     // 获得补位所用的字符
     char padChr = chr(amountToPad);
-    String tmp = new String();
+    StringBuilder tmp = new StringBuilder();
     for (int index = 0; index < amountToPad; index++) {
-      tmp += padChr;
+      tmp.append(padChr);
     }
-    return tmp.getBytes(CHARSET);
+    return tmp.toString().getBytes(CHARSET);
   }
 
   /**
-   * 删除解密后明文的补位字符
+   * 删除解密后明文的补位字符.
    *
    * @param decrypted 解密后的明文
    * @return 删除补位字符后的明文
@@ -55,12 +52,12 @@ public class PKCS7Encoder {
   }
 
   /**
-   * 将数字转化成ASCII码对应的字符，用于对明文进行补码
+   * 将数字转化成ASCII码对应的字符，用于对明文进行补码.
    *
    * @param a 需要转化的数字
    * @return 转化得到的字符
    */
-  public static char chr(int a) {
+  private static char chr(int a) {
     byte target = (byte) (a & 0xFF);
     return (char) target;
   }
diff --git a/weixin-java-common/src/main/java/me/chanjar/weixin/common/util/crypto/WxCryptUtil.java b/weixin-java-common/src/main/java/me/chanjar/weixin/common/util/crypto/WxCryptUtil.java
index f16d3bd3e..73aa6d7a1 100755
--- a/weixin-java-common/src/main/java/me/chanjar/weixin/common/util/crypto/WxCryptUtil.java
+++ b/weixin-java-common/src/main/java/me/chanjar/weixin/common/util/crypto/WxCryptUtil.java
@@ -1,21 +1,21 @@
 package me.chanjar.weixin.common.util.crypto;
 
-import org.apache.commons.codec.binary.Base64;
-import org.w3c.dom.Document;
-import org.w3c.dom.Element;
-import org.xml.sax.InputSource;
-
+import java.io.StringReader;
+import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
+import java.util.Arrays;
+import java.util.Random;
 import javax.crypto.Cipher;
 import javax.crypto.spec.IvParameterSpec;
 import javax.crypto.spec.SecretKeySpec;
 import javax.xml.parsers.DocumentBuilder;
 import javax.xml.parsers.DocumentBuilderFactory;
 import javax.xml.parsers.ParserConfigurationException;
-import java.io.StringReader;
-import java.nio.charset.Charset;
-import java.nio.charset.StandardCharsets;
-import java.util.Arrays;
-import java.util.Random;
+
+import org.apache.commons.codec.binary.Base64;
+import org.w3c.dom.Document;
+import org.w3c.dom.Element;
+import org.xml.sax.InputSource;
 
 /**
  * <pre>
@@ -25,6 +25,8 @@ import java.util.Random;
  * 需要导入架包commons-codec-1.9（或commons-codec-1.8等其他版本）
  * 官方下载地址：http://commons.apache.org/proper/commons-codec/download_codec.cgi
  * </pre>
+ *
+ * @author Tencent
  */
 public class WxCryptUtil {
 
@@ -164,8 +166,7 @@ public class WxCryptUtil {
     ByteGroup byteCollector = new ByteGroup();
     byte[] randomStringBytes = randomStr.getBytes(CHARSET);
     byte[] plainTextBytes = plainText.getBytes(CHARSET);
-    byte[] bytesOfSizeInNetworkOrder = number2BytesInNetworkOrder(
-      plainTextBytes.length);
+    byte[] bytesOfSizeInNetworkOrder = number2BytesInNetworkOrder(plainTextBytes.length);
     byte[] appIdBytes = this.appidOrCorpid.getBytes(CHARSET);
 
     // randomStr + networkBytesOrder + text + appid
@@ -252,7 +253,7 @@ public class WxCryptUtil {
       throw new RuntimeException(e);
     }
 
-    String xmlContent, from_appid;
+    String xmlContent, fromAppid;
     try {
       // 去除补位字符
       byte[] bytes = PKCS7Encoder.decode(original);
@@ -264,14 +265,14 @@ public class WxCryptUtil {
 
       xmlContent = new String(Arrays.copyOfRange(bytes, 20, 20 + xmlLength),
         CHARSET);
-      from_appid = new String(
+      fromAppid = new String(
         Arrays.copyOfRange(bytes, 20 + xmlLength, bytes.length), CHARSET);
     } catch (Exception e) {
       throw new RuntimeException(e);
     }
 
     // appid不相同的情况
-    if (!from_appid.equals(this.appidOrCorpid)) {
+    if (!fromAppid.equals(this.appidOrCorpid)) {
       throw new RuntimeException("AppID不正确");
     }
 
diff --git a/weixin-java-common/src/main/java/me/chanjar/weixin/common/util/http/URIUtil.java b/weixin-java-common/src/main/java/me/chanjar/weixin/common/util/http/URIUtil.java
index 7e42aba72..4e45c65d6 100644
--- a/weixin-java-common/src/main/java/me/chanjar/weixin/common/util/http/URIUtil.java
+++ b/weixin-java-common/src/main/java/me/chanjar/weixin/common/util/http/URIUtil.java
@@ -1,9 +1,9 @@
 package me.chanjar.weixin.common.util.http;
 
 
-import org.apache.commons.lang3.StringUtils;
+import java.nio.charset.StandardCharsets;
 
-import java.io.UnsupportedEncodingException;
+import org.apache.commons.lang3.StringUtils;
 
 public class URIUtil {
 
@@ -16,27 +16,22 @@ public class URIUtil {
 
     int l = input.length();
     StringBuilder o = new StringBuilder(l * 3);
-    try {
-      for (int i = 0; i < l; i++) {
-        String e = input.substring(i, i + 1);
-        if (ALLOWED_CHARS.indexOf(e) == -1) {
-          byte[] b = e.getBytes("utf-8");
-          o.append(getHex(b));
-          continue;
-        }
-        o.append(e);
+    for (int i = 0; i < l; i++) {
+      String e = input.substring(i, i + 1);
+      if (!ALLOWED_CHARS.contains(e)) {
+        byte[] b = e.getBytes(StandardCharsets.UTF_8);
+        o.append(getHex(b));
+        continue;
       }
-      return o.toString();
-    } catch (UnsupportedEncodingException e) {
-      e.printStackTrace();
+      o.append(e);
     }
-    return input;
+    return o.toString();
   }
 
-  private static String getHex(byte buf[]) {
+  private static String getHex(byte[] buf) {
     StringBuilder o = new StringBuilder(buf.length * 3);
-    for (int i = 0; i < buf.length; i++) {
-      int n = buf[i] & 0xff;
+    for (byte aBuf : buf) {
+      int n = aBuf & 0xff;
       o.append("%");
       if (n < 0x10) {
         o.append("0");
diff --git a/weixin-java-pay/src/main/java/com/github/binarywang/wxpay/bean/notify/WxPayRefundNotifyResult.java b/weixin-java-pay/src/main/java/com/github/binarywang/wxpay/bean/notify/WxPayRefundNotifyResult.java
index f738984a8..9ba49ccff 100644
--- a/weixin-java-pay/src/main/java/com/github/binarywang/wxpay/bean/notify/WxPayRefundNotifyResult.java
+++ b/weixin-java-pay/src/main/java/com/github/binarywang/wxpay/bean/notify/WxPayRefundNotifyResult.java
@@ -1,6 +1,7 @@
 package com.github.binarywang.wxpay.bean.notify;
 
 import java.io.Serializable;
+import java.nio.charset.StandardCharsets;
 import javax.crypto.Cipher;
 import javax.crypto.spec.SecretKeySpec;
 
@@ -48,7 +49,7 @@ public class WxPayRefundNotifyResult extends BaseWxPayResult implements Serializ
     String reqInfoString = result.getReqInfoString();
     try {
       final String keyMd5String = DigestUtils.md5Hex(mchKey).toLowerCase();
-      SecretKeySpec key = new SecretKeySpec(keyMd5String.getBytes(), "AES");
+      SecretKeySpec key = new SecretKeySpec(keyMd5String.getBytes(StandardCharsets.UTF_8), "AES");
 
       Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
       cipher.init(Cipher.DECRYPT_MODE, key);
diff --git a/weixin-java-pay/src/main/java/com/github/binarywang/wxpay/bean/result/BaseWxPayResult.java b/weixin-java-pay/src/main/java/com/github/binarywang/wxpay/bean/result/BaseWxPayResult.java
index ad014fc2a..47015df92 100644
--- a/weixin-java-pay/src/main/java/com/github/binarywang/wxpay/bean/result/BaseWxPayResult.java
+++ b/weixin-java-pay/src/main/java/com/github/binarywang/wxpay/bean/result/BaseWxPayResult.java
@@ -4,6 +4,7 @@ import java.io.ByteArrayInputStream;
 import java.io.IOException;
 import java.io.Serializable;
 import java.math.BigDecimal;
+import java.nio.charset.StandardCharsets;
 import java.util.List;
 import java.util.Map;
 import javax.xml.parsers.DocumentBuilderFactory;
@@ -192,7 +193,7 @@ public abstract class BaseWxPayResult implements Serializable {
       this.xmlDoc = DocumentBuilderFactory
         .newInstance()
         .newDocumentBuilder()
-        .parse(new ByteArrayInputStream(this.xmlString.getBytes("UTF-8")));
+        .parse(new ByteArrayInputStream(this.xmlString.getBytes(StandardCharsets.UTF_8)));
       return xmlDoc;
     } catch (SAXException | IOException | ParserConfigurationException e) {
       throw new RuntimeException("非法的xml文本内容：" + this.xmlString);
diff --git a/weixin-java-pay/src/main/java/com/github/binarywang/wxpay/service/impl/EntPayServiceImpl.java b/weixin-java-pay/src/main/java/com/github/binarywang/wxpay/service/impl/EntPayServiceImpl.java
index 5be2113b3..d694f42e7 100644
--- a/weixin-java-pay/src/main/java/com/github/binarywang/wxpay/service/impl/EntPayServiceImpl.java
+++ b/weixin-java-pay/src/main/java/com/github/binarywang/wxpay/service/impl/EntPayServiceImpl.java
@@ -3,6 +3,7 @@ package com.github.binarywang.wxpay.service.impl;
 import java.io.File;
 import java.io.FileReader;
 import java.io.IOException;
+import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.security.PublicKey;
@@ -126,7 +127,7 @@ public class EntPayServiceImpl implements EntPayService {
           .getPublicKey((SubjectPublicKeyInfo) reader.readObject());
 
         cipher.init(Cipher.ENCRYPT_MODE, publicKey);
-        byte[] encrypt = cipher.doFinal(srcString.getBytes());
+        byte[] encrypt = cipher.doFinal(srcString.getBytes(StandardCharsets.UTF_8));
         return Base64.encodeBase64String(encrypt);
       }
     } catch (Exception e) {
@@ -138,7 +139,7 @@ public class EntPayServiceImpl implements EntPayService {
     try {
       String publicKeyStr = this.getPublicKey();
       Path tmpFile = Files.createTempFile("payToBank", ".pem");
-      Files.write(tmpFile, publicKeyStr.getBytes());
+      Files.write(tmpFile, publicKeyStr.getBytes(StandardCharsets.UTF_8));
       return tmpFile.toFile();
     } catch (Exception e) {
       throw new WxPayException("生成加密公钥文件时发生异常", e);
@@ -162,7 +163,7 @@ public class EntPayServiceImpl implements EntPayService {
       "p7kM7BoaY2goFgYAe4DsI8Fh33dCOiKyVwIDAQAB\n" +
       "-----END RSA PUBLIC KEY-----";
     Path tmpFile = Files.createTempFile("payToBank", ".pem");
-    Files.write(tmpFile, key.getBytes());
+    Files.write(tmpFile, key.getBytes(StandardCharsets.UTF_8));
     System.out.println(new EntPayServiceImpl(null).encryptRSA(tmpFile.toFile(), "111111"));
   }
 
diff --git a/weixin-java-pay/src/test/java/com/github/binarywang/wxpay/bean/notify/WxPayRefundNotifyResultTest.java b/weixin-java-pay/src/test/java/com/github/binarywang/wxpay/bean/notify/WxPayRefundNotifyResultTest.java
index 4b99b7693..ba7ed5450 100644
--- a/weixin-java-pay/src/test/java/com/github/binarywang/wxpay/bean/notify/WxPayRefundNotifyResultTest.java
+++ b/weixin-java-pay/src/test/java/com/github/binarywang/wxpay/bean/notify/WxPayRefundNotifyResultTest.java
@@ -1,19 +1,20 @@
 package com.github.binarywang.wxpay.bean.notify;
 
+import java.math.BigInteger;
+import java.nio.charset.StandardCharsets;
+import java.security.MessageDigest;
+import javax.crypto.Cipher;
+import javax.crypto.spec.SecretKeySpec;
+import javax.inject.Inject;
+
+import org.apache.commons.codec.binary.Base64;
+import org.testng.annotations.*;
+
 import com.github.binarywang.wxpay.config.WxPayConfig;
 import com.github.binarywang.wxpay.exception.WxPayException;
 import com.github.binarywang.wxpay.testbase.ApiTestModule;
-import org.apache.commons.codec.binary.Base64;
-import org.testng.annotations.Guice;
-import org.testng.annotations.Test;
 
-import javax.crypto.Cipher;
-import javax.crypto.spec.SecretKeySpec;
-import javax.inject.Inject;
-import java.math.BigInteger;
-import java.security.MessageDigest;
-
-import static org.testng.Assert.assertNotNull;
+import static org.testng.Assert.*;
 
 /**
  * <pre>
@@ -71,10 +72,10 @@ public class WxPayRefundNotifyResultTest {
 
     Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
     final MessageDigest md5 = MessageDigest.getInstance("MD5");
-    md5.update(this.wxPayConfig.getMchKey().getBytes());
+    md5.update(this.wxPayConfig.getMchKey().getBytes(StandardCharsets.UTF_8));
     final String keyMd5String = new BigInteger(1, md5.digest()).toString(16).toLowerCase();
-    SecretKeySpec key = new SecretKeySpec(keyMd5String.getBytes(), "AES");
+    SecretKeySpec key = new SecretKeySpec(keyMd5String.getBytes(StandardCharsets.UTF_8), "AES");
     cipher.init(Cipher.ENCRYPT_MODE, key);
-    System.out.println(Base64.encodeBase64String(cipher.doFinal(xml.getBytes())));
+    System.out.println(Base64.encodeBase64String(cipher.doFinal(xml.getBytes(StandardCharsets.UTF_8))));
   }
 }