[Improvement][alert] Refactor alert module to fix code smell (#4434)

* chore: Refactore dolphinscheduler-alert to fix code smell

* chore: Refactor code to fix codestyle error

dolphinscheduler-alert/src/main/java/org/apache/dolphinscheduler/alert/AlertServer.java

@@ -14,6 +14,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package org.apache.dolphinscheduler.alert;
 
 import org.apache.dolphinscheduler.alert.plugin.EmailAlertPlugin;
@@ -25,11 +26,12 @@ import org.apache.dolphinscheduler.common.thread.Stopper;
 import org.apache.dolphinscheduler.dao.AlertDao;
 import org.apache.dolphinscheduler.dao.DaoFactory;
 import org.apache.dolphinscheduler.dao.entity.Alert;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 import java.util.List;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 /**
  * alert of start
  */
@@ -40,8 +42,6 @@ public class AlertServer {
      */
     private AlertDao alertDao = DaoFactory.getDaoInstance(AlertDao.class);
 
-    private AlertSender alertSender;
-
     private static AlertServer instance;
 
     private FilePluginManager alertPluginManager;
@@ -61,7 +61,7 @@ public class AlertServer {
         alertPluginManager.addPlugin(new EmailAlertPlugin());
     }
 
-    public synchronized static AlertServer getInstance() {
+    public static synchronized AlertServer getInstance() {
         if (null == instance) {
             instance = new AlertServer();
         }
@@ -78,12 +78,11 @@ public class AlertServer {
                 Thread.currentThread().interrupt();
             }
             List<Alert> alerts = alertDao.listWaitExecutionAlert();
-            alertSender = new AlertSender(alerts, alertDao, alertPluginManager);
+            AlertSender alertSender = new AlertSender(alerts, alertDao, alertPluginManager);
             alertSender.run();
         }
     }
 
-
     public static void main(String[] args) {
         AlertServer alertServer = AlertServer.getInstance();
         alertServer.start();

dolphinscheduler-alert/src/main/java/org/apache/dolphinscheduler/alert/manager/DingTalkManager.java

@@ -14,23 +14,25 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package org.apache.dolphinscheduler.alert.manager;
 
 import org.apache.dolphinscheduler.alert.utils.Constants;
 import org.apache.dolphinscheduler.alert.utils.DingTalkUtils;
 import org.apache.dolphinscheduler.plugin.model.AlertInfo;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 import java.io.IOException;
 import java.util.HashMap;
 import java.util.Map;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 /**
  * Ding Talk Manager
  */
 public class DingTalkManager {
-    private static final Logger logger = LoggerFactory.getLogger(EnterpriseWeChatManager.class);
+    private static final Logger logger = LoggerFactory.getLogger(DingTalkManager.class);
 
     public Map<String, Object> send(AlertInfo alert) {
         Map<String, Object> retMap = new HashMap<>();
@@ -47,7 +49,6 @@ public class DingTalkManager {
     }
 
     private String buildMessage(AlertInfo alert) {
-        String msg = alert.getAlertData().getContent();
+        return alert.getAlertData().getContent();
-        return msg;
     }
 }

dolphinscheduler-alert/src/main/java/org/apache/dolphinscheduler/alert/plugin/EmailAlertPlugin.java

@@ -14,6 +14,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package org.apache.dolphinscheduler.alert.plugin;
 
 import org.apache.dolphinscheduler.alert.manager.DingTalkManager;
@@ -28,14 +29,19 @@ import org.apache.dolphinscheduler.plugin.api.AlertPlugin;
 import org.apache.dolphinscheduler.plugin.model.AlertData;
 import org.apache.dolphinscheduler.plugin.model.AlertInfo;
 import org.apache.dolphinscheduler.plugin.model.PluginName;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import java.util.*;
-
 /**
  * EmailAlertPlugin
- *
+ * <p>
  * This plugin is a default plugin, and mix up email and enterprise wechat, because adapt with former alert behavior
  */
 public class EmailAlertPlugin implements AlertPlugin {
@@ -125,7 +131,7 @@ public class EmailAlertPlugin implements AlertPlugin {
                 }
             }
 
-           if (DingTalkUtils.isEnableDingTalk) {
+            if (DingTalkUtils.IS_ENABLE_DING_TALK) {
                 logger.info("Ding Talk is enable.");
                 dingTalkManager.send(info);
             }

dolphinscheduler-alert/src/main/java/org/apache/dolphinscheduler/alert/template/AlertTemplateFactory.java

@@ -14,23 +14,22 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package org.apache.dolphinscheduler.alert.template;
 
 import org.apache.dolphinscheduler.alert.template.impl.DefaultHTMLTemplate;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 /**
  * the alert template factory
  */
 public class AlertTemplateFactory {
 
-    private static final Logger logger = LoggerFactory.getLogger(AlertTemplateFactory.class);
+    private AlertTemplateFactory() {
-
+    }
-    private AlertTemplateFactory(){}
 
     /**
      * get a template from alert.properties conf file
+     *
      * @return a template, default is DefaultHTMLTemplate
      */
     public static AlertTemplate getMessageTemplate() {

dolphinscheduler-alert/src/main/java/org/apache/dolphinscheduler/alert/template/impl/DefaultHTMLTemplate.java

@@ -14,21 +14,29 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package org.apache.dolphinscheduler.alert.template.impl;
 
-import com.fasterxml.jackson.databind.JsonNode;
+import static org.apache.dolphinscheduler.common.utils.Preconditions.checkNotNull;
-import com.fasterxml.jackson.databind.node.ArrayNode;
+
 import org.apache.dolphinscheduler.alert.template.AlertTemplate;
 import org.apache.dolphinscheduler.alert.utils.Constants;
 import org.apache.dolphinscheduler.common.enums.ShowType;
+import org.apache.dolphinscheduler.common.utils.JSONUtils;
 import org.apache.dolphinscheduler.common.utils.StringUtils;
+
+import java.util.Iterator;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Set;
+
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
-import org.apache.dolphinscheduler.common.utils.*;
-
-import java.util.*;
 
-import static org.apache.dolphinscheduler.common.utils.Preconditions.*;
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.node.ArrayNode;
 
 /**
  * the default html alert message template
@@ -37,7 +45,6 @@ public class DefaultHTMLTemplate implements AlertTemplate {
 
     public static final Logger logger = LoggerFactory.getLogger(DefaultHTMLTemplate.class);
 
-
     @Override
     public String getMessageFromTemplate(String content, ShowType showType, boolean showAll) {
 
@@ -45,7 +52,7 @@ public class DefaultHTMLTemplate implements AlertTemplate {
             case TABLE:
                 return getTableTypeMessage(content, showAll);
             case TEXT:
-                return getTextTypeMessage(content,showAll);
+                return getTextTypeMessage(content);
             default:
                 throw new IllegalArgumentException(String.format("not support showType: %s in DefaultHTMLTemplate", showType));
         }
@@ -53,6 +60,7 @@ public class DefaultHTMLTemplate implements AlertTemplate {
 
     /**
      * get alert message which type is TABLE
+     *
      * @param content message content
      * @param showAll weather to show all
      * @return alert message
@@ -73,9 +81,9 @@ public class DefaultHTMLTemplate implements AlertTemplate {
             String title = "";
             for (LinkedHashMap mapItems : mapItemsList) {
 
-                Set<Map.Entry<String, Object>> entries = mapItems.entrySet();
+                Set<Entry<String, Object>> entries = mapItems.entrySet();
 
-                Iterator<Map.Entry<String, Object>> iterator = entries.iterator();
+                Iterator<Entry<String, Object>> iterator = entries.iterator();
 
                 StringBuilder t = new StringBuilder(Constants.TR);
                 StringBuilder cs = new StringBuilder(Constants.TR);
@@ -103,11 +111,11 @@ public class DefaultHTMLTemplate implements AlertTemplate {
 
     /**
      * get alert message which type is TEXT
+     *
      * @param content message content
-     * @param showAll weather to show all
      * @return alert message
      */
-    private String getTextTypeMessage(String content,boolean showAll){
+    private String getTextTypeMessage(String content) {
 
         if (StringUtils.isNotEmpty(content)) {
             ArrayNode list = JSONUtils.parseArray(content);
@@ -127,6 +135,7 @@ public class DefaultHTMLTemplate implements AlertTemplate {
 
     /**
      * get alert message from a html template
+     *
      * @param title message title
      * @param content message content
      * @return alert message which use html template
@@ -134,7 +143,7 @@ public class DefaultHTMLTemplate implements AlertTemplate {
     private String getMessageFromHtmlTemplate(String title, String content) {
 
         checkNotNull(content);
-        String htmlTableThead = StringUtils.isEmpty(title) ? "" : String.format("<thead>%s</thead>\n",title);
+        String htmlTableThead = StringUtils.isEmpty(title) ? "" : String.format("<thead>%s</thead>%n", title);
 
         return Constants.HTML_HEADER_PREFIX + htmlTableThead + content + Constants.TABLE_BODY_HTML_TAIL;
     }

dolphinscheduler-alert/src/main/java/org/apache/dolphinscheduler/alert/utils/Constants.java

@@ -14,6 +14,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package org.apache.dolphinscheduler.alert.utils;
 
 /**
@@ -23,6 +24,7 @@ public class Constants {
     private Constants() {
         throw new IllegalStateException("Constants class");
     }
+
     /**
      * alert properties path
      */
@@ -174,7 +176,13 @@ public class Constants {
 
     public static final String DINGTALK_ENABLE = "dingtalk.isEnable";
 
-    public static final String HTML_HEADER_PREFIX = "<!DOCTYPE HTML PUBLIC '-//W3C//DTD HTML 4.01 Transitional//EN' 'http://www.w3.org/TR/html4/loose.dtd'><html><head><title>dolphinscheduler</title><meta name='Keywords' content=''><meta name='Description' content=''><style type=\"text/css\">table {margin-top:0px;padding-top:0px;border:1px solid;font-size: 14px;color: #333333;border-width: 1px;border-color: #666666;border-collapse: collapse;}table th {border-width: 1px;padding: 8px;border-style: solid;border-color: #666666;background-color: #dedede;text-align: left;}table td {border-width: 1px;padding: 8px;border-style: solid;border-color: #666666;background-color: #ffffff;text-align: left;}</style></head><body style=\"margin:0;padding:0\"><table border=\"1px\" cellpadding=\"5px\" cellspacing=\"-10px\"> ";
+    public static final String HTML_HEADER_PREFIX = "<!DOCTYPE HTML PUBLIC '-//W3C//DTD HTML 4.01 Transitional//EN' 'http://www.w3.org/TR/html4/loose.dtd'>"
+            + "<html><head><title>dolphinscheduler</title><meta name='Keywords' content=''>"
+            + "<meta name='Description' content=''>"
+            + "<style type=\"text/css\">table {margin-top:0px;padding-top:0px;border:1px solid;font-size: 14px;color: #333333;border-width: 1px;border-color: #666666;border-collapse: collapse;}"
+            + "table th {border-width: 1px;padding: 8px;border-style: solid;border-color: #666666;background-color: #dedede;text-align: left;}"
+            + "table td {border-width: 1px;padding: 8px;border-style: solid;border-color: #666666;background-color: #ffffff;text-align: left;}</style>"
+            + "/head><body style=\"margin:0;padding:0\"><table border=\"1px\" cellpadding=\"5px\" cellspacing=\"-10px\"> ";
 
     public static final String TABLE_BODY_HTML_TAIL = "</table></body></html>";
 

dolphinscheduler-alert/src/main/java/org/apache/dolphinscheduler/alert/utils/DingTalkUtils.java

@@ -14,10 +14,11 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package org.apache.dolphinscheduler.alert.utils;
 
+package org.apache.dolphinscheduler.alert.utils;
 
 import org.apache.dolphinscheduler.common.utils.*;
+
 import org.apache.commons.codec.binary.StringUtils;
 import org.apache.http.HttpEntity;
 import org.apache.http.HttpHost;
@@ -32,44 +33,50 @@ import org.apache.http.impl.client.BasicCredentialsProvider;
 import org.apache.http.impl.client.CloseableHttpClient;
 import org.apache.http.impl.client.HttpClients;
 import org.apache.http.util.EntityUtils;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 import java.io.IOException;
 import java.util.HashMap;
 import java.util.Map;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 /**
  * DingTalkUtils utils
  * support send msg to ding talk by robot message push function.
- * support proxy setting
+ * support PROXY setting
  */
 public class DingTalkUtils {
     public static final Logger logger = LoggerFactory.getLogger(DingTalkUtils.class);
 
-    public static final boolean isEnableDingTalk = PropertyUtils.getBoolean(Constants.DINGTALK_ENABLE);
+    public static final boolean IS_ENABLE_DING_TALK = PropertyUtils.getBoolean(Constants.DINGTALK_ENABLE);
-    private static final String dingTaskUrl = PropertyUtils.getString(Constants.DINGTALK_WEBHOOK);
+    private static final String DING_TASK_URL = PropertyUtils.getString(Constants.DINGTALK_WEBHOOK);
-    private static final String keyword = PropertyUtils.getString(Constants.DINGTALK_KEYWORD);
+    private static final String KEYWORD = PropertyUtils.getString(Constants.DINGTALK_KEYWORD);
-    private static final Boolean isEnableProxy = PropertyUtils.getBoolean(Constants.DINGTALK_PROXY_ENABLE);
+    private static final Boolean IS_ENABLE_PROXY = PropertyUtils.getBoolean(Constants.DINGTALK_PROXY_ENABLE);
-    private static final String proxy = PropertyUtils.getString(Constants.DINGTALK_PROXY);
+    private static final String PROXY = PropertyUtils.getString(Constants.DINGTALK_PROXY);
-    private static final String user = PropertyUtils.getString(Constants.DINGTALK_USER);
+    private static final String USER = PropertyUtils.getString(Constants.DINGTALK_USER);
-    private static final String passwd = PropertyUtils.getString(Constants.DINGTALK_PASSWORD);
+    private static final String PASSWD = PropertyUtils.getString(Constants.DINGTALK_PASSWORD);
-    private static final Integer port = PropertyUtils.getInt(Constants.DINGTALK_PORT);
+    private static final Integer PORT = PropertyUtils.getInt(Constants.DINGTALK_PORT);
+
+    private DingTalkUtils() {
+        throw new IllegalStateException(DingTalkUtils.class.getName());
+    }
 
     /**
      * send message interface
      * only support text message format now.
+     *
      * @param msg message context to send
      * @param charset charset type
      * @return result of sending msg
      * @throws IOException the IOException
      */
     public static String sendDingTalkMsg(String msg, String charset) throws IOException {
-        String msgToJson = textToJsonString(msg + "#" + keyword);
+        String msgToJson = textToJsonString(msg + "#" + KEYWORD);
         HttpPost httpPost = constructHttpPost(msgToJson, charset);
 
         CloseableHttpClient httpClient;
-        if (isEnableProxy) {
+        if (Boolean.TRUE.equals(IS_ENABLE_PROXY)) {
             httpClient = getProxyClient();
             RequestConfig rcf = getProxyConfig();
             httpPost.setConfig(rcf);
@@ -87,7 +94,7 @@ public class DingTalkUtils {
             } finally {
                 response.close();
             }
-            logger.info("Ding Talk send [{}], resp:{%s}", msg, resp);
+            logger.info("Ding Talk send [{}], resp:{%s}", msg);
             return resp;
         } finally {
             httpClient.close();
@@ -95,20 +102,18 @@ public class DingTalkUtils {
     }
 
     public static HttpPost constructHttpPost(String msg, String charset) {
-        HttpPost post =  new HttpPost(dingTaskUrl);
+        HttpPost post = new HttpPost(DING_TASK_URL);
         StringEntity entity = new StringEntity(msg, charset);
         post.setEntity(entity);
         post.addHeader("Content-Type", "application/json; charset=utf-8");
         return post;
     }
 
-
     public static CloseableHttpClient getProxyClient() {
-        HttpHost httpProxy = new HttpHost(proxy, port);
+        HttpHost httpProxy = new HttpHost(PROXY, PORT);
         CredentialsProvider provider = new BasicCredentialsProvider();
-        provider.setCredentials(new AuthScope(httpProxy), new UsernamePasswordCredentials(user, passwd));
+        provider.setCredentials(new AuthScope(httpProxy), new UsernamePasswordCredentials(USER, PASSWD));
-        CloseableHttpClient httpClient = HttpClients.custom().setDefaultCredentialsProvider(provider).build();
+        return HttpClients.custom().setDefaultCredentialsProvider(provider).build();
-        return httpClient;
     }
 
     public static CloseableHttpClient getDefaultClient() {
@@ -116,14 +121,14 @@ public class DingTalkUtils {
     }
 
     public static RequestConfig getProxyConfig() {
-        HttpHost httpProxy = new HttpHost(proxy, port);
+        HttpHost httpProxy = new HttpHost(PROXY, PORT);
         return RequestConfig.custom().setProxy(httpProxy).build();
     }
 
     public static String textToJsonString(String text) {
-        Map<String, Object> items = new HashMap<String, Object>();
+        Map<String, Object> items = new HashMap<>();
         items.put("msgtype", "text");
-        Map<String, String> textContent = new HashMap<String, String>();
+        Map<String, String> textContent = new HashMap<>();
         byte[] byt = StringUtils.getBytesUtf8(text);
         String txt = StringUtils.newStringUtf8(byt);
         textContent.put("content", txt);

dolphinscheduler-alert/src/main/java/org/apache/dolphinscheduler/alert/utils/EnterpriseWeChatUtils.java

@@ -60,9 +60,13 @@ public class EnterpriseWeChatUtils {
     private static final String ENTERPRISE_WE_CHAT_TEAM_SEND_MSG = PropertyUtils.getString(Constants.ENTERPRISE_WECHAT_TEAM_SEND_MSG);
     private static final String ENTERPRISE_WE_CHAT_USER_SEND_MSG = PropertyUtils.getString(Constants.ENTERPRISE_WECHAT_USER_SEND_MSG);
 
-    private static final String agentIdRegExp = "\\{agentId}";
+    private static final String AGENT_ID_REG_EXP = "\\{agentId}";
-    private static final String msgRegExp = "\\{msg}";
+    private static final String MSG_REG_EXP = "\\{msg}";
-    private static final String userRegExp = "\\{toUser}";
+    private static final String USER_REG_EXP = "\\{toUser}";
+
+    private EnterpriseWeChatUtils() {
+        throw new IllegalStateException(EnterpriseWeChatUtils.class.getName());
+    }
 
     /**
      * get Enterprise WeChat is enable
@@ -120,8 +124,8 @@ public class EnterpriseWeChatUtils {
      */
     public static String makeTeamSendMsg(String toParty, String agentId, String msg) {
         return ENTERPRISE_WE_CHAT_TEAM_SEND_MSG.replaceAll("\\{toParty}", toParty)
-                .replaceAll(agentIdRegExp, agentId)
+                .replaceAll(AGENT_ID_REG_EXP, agentId)
-                .replaceAll(msgRegExp, msg);
+                .replaceAll(MSG_REG_EXP, msg);
     }
 
     /**
@@ -135,8 +139,8 @@ public class EnterpriseWeChatUtils {
     public static String makeTeamSendMsg(Collection<String> toParty, String agentId, String msg) {
         String listParty = FuncUtils.mkString(toParty, "|");
         return ENTERPRISE_WE_CHAT_TEAM_SEND_MSG.replaceAll("\\{toParty}", listParty)
-                .replaceAll(agentIdRegExp, agentId)
+                .replaceAll(AGENT_ID_REG_EXP, agentId)
-                .replaceAll(msgRegExp, msg);
+                .replaceAll(MSG_REG_EXP, msg);
     }
 
     /**
@@ -148,9 +152,9 @@ public class EnterpriseWeChatUtils {
      * @return Enterprise WeChat send message
      */
     public static String makeUserSendMsg(String toUser, String agentId, String msg) {
-        return ENTERPRISE_WE_CHAT_USER_SEND_MSG.replaceAll("\\{toUser}", toUser)
+        return ENTERPRISE_WE_CHAT_USER_SEND_MSG.replaceAll(USER_REG_EXP, toUser)
-                .replaceAll(agentIdRegExp, agentId)
+                .replaceAll(AGENT_ID_REG_EXP, agentId)
-                .replaceAll(msgRegExp, msg);
+                .replaceAll(MSG_REG_EXP, msg);
     }
 
     /**
@@ -163,9 +167,9 @@ public class EnterpriseWeChatUtils {
      */
     public static String makeUserSendMsg(Collection<String> toUser, String agentId, String msg) {
         String listUser = FuncUtils.mkString(toUser, "|");
-        return ENTERPRISE_WE_CHAT_USER_SEND_MSG.replaceAll(userRegExp, listUser)
+        return ENTERPRISE_WE_CHAT_USER_SEND_MSG.replaceAll(USER_REG_EXP, listUser)
-                .replaceAll(agentIdRegExp, agentId)
+                .replaceAll(AGENT_ID_REG_EXP, agentId)
-                .replaceAll(msgRegExp, msg);
+                .replaceAll(MSG_REG_EXP, msg);
     }
 
     /**

dolphinscheduler-alert/src/main/java/org/apache/dolphinscheduler/alert/utils/ExcelUtils.java

@@ -14,23 +14,29 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package org.apache.dolphinscheduler.alert.utils;
 
 import org.apache.dolphinscheduler.common.utils.CollectionUtils;
+import org.apache.dolphinscheduler.common.utils.JSONUtils;
+
 import org.apache.poi.hssf.usermodel.HSSFCell;
 import org.apache.poi.hssf.usermodel.HSSFRow;
 import org.apache.poi.hssf.usermodel.HSSFSheet;
 import org.apache.poi.hssf.usermodel.HSSFWorkbook;
 import org.apache.poi.ss.usermodel.CellStyle;
 import org.apache.poi.ss.usermodel.HorizontalAlignment;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
-import java.util.*;
+import java.util.ArrayList;
-import org.apache.dolphinscheduler.common.utils.*;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * excel utils
@@ -38,8 +44,14 @@ import org.apache.dolphinscheduler.common.utils.*;
 public class ExcelUtils {
 
     private static final Logger logger = LoggerFactory.getLogger(ExcelUtils.class);
+
+    private ExcelUtils() {
+        throw new IllegalStateException(ExcelUtils.class.getName());
+    }
+
     /**
      * generate excel file
+     *
      * @param content the content
      * @param title the title
      * @param xlsFilePath the xls path
@@ -59,9 +71,7 @@ public class ExcelUtils {
 
         List<String> headerList = new ArrayList<>();
 
-        Iterator<Map.Entry<String, Object>> iter = headerMap.entrySet().iterator();
+        for (Map.Entry<String, Object> en : headerMap.entrySet()) {
-        while (iter.hasNext()){
-            Map.Entry<String, Object> en = iter.next();
             headerList.add(en.getKey());
         }
 
@@ -117,7 +127,6 @@ public class ExcelUtils {
             wb.write(fos);
 
         } catch (Exception e) {
-               logger.error("generate excel error",e);
             throw new RuntimeException("generate excel error", e);
         } finally {
             if (wb != null) {

dolphinscheduler-alert/src/main/java/org/apache/dolphinscheduler/alert/utils/FuncUtils.java

@@ -14,12 +14,17 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package org.apache.dolphinscheduler.alert.utils;
 
 import org.apache.dolphinscheduler.common.utils.StringUtils;
 
 public class FuncUtils {
 
+    private FuncUtils() {
+        throw new IllegalStateException(FuncUtils.class.getName());
+    }
+
     public static String mkString(Iterable<String> list, String split) {
 
         if (null == list || StringUtils.isEmpty(split)) {

dolphinscheduler-alert/src/main/java/org/apache/dolphinscheduler/alert/utils/MailUtils.java

@@ -14,23 +14,39 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package org.apache.dolphinscheduler.alert.utils;
 
 import org.apache.dolphinscheduler.alert.template.AlertTemplate;
 import org.apache.dolphinscheduler.alert.template.AlertTemplateFactory;
 import org.apache.dolphinscheduler.common.enums.ShowType;
-import org.apache.commons.mail.EmailException;
-import org.apache.commons.mail.HtmlEmail;
 import org.apache.dolphinscheduler.common.utils.CollectionUtils;
 import org.apache.dolphinscheduler.common.utils.StringUtils;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
-import javax.mail.*;
+import org.apache.commons.mail.EmailException;
-import javax.mail.internet.*;
+import org.apache.commons.mail.HtmlEmail;
-import java.io.*;
+
-import java.util.*;
+import java.io.File;
+import java.io.IOException;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Properties;
+
+import javax.mail.Authenticator;
+import javax.mail.Message;
+import javax.mail.MessagingException;
+import javax.mail.PasswordAuthentication;
+import javax.mail.Session;
+import javax.mail.Transport;
+import javax.mail.internet.InternetAddress;
+import javax.mail.internet.MimeBodyPart;
+import javax.mail.internet.MimeMessage;
+import javax.mail.internet.MimeMultipart;
+import javax.mail.internet.MimeUtility;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * mail utils
@@ -55,7 +71,7 @@ public class MailUtils {
 
     public static final Boolean MAIL_USE_SSL = PropertyUtils.getBoolean(Constants.MAIL_SMTP_SSL_ENABLE);
 
-    public static final String xlsFilePath = PropertyUtils.getString(Constants.XLS_FILE_PATH,"/tmp/xls");
+    public static final String XLS_FILE_PATH = PropertyUtils.getString(Constants.XLS_FILE_PATH, "/tmp/xls");
 
     public static final String STARTTLS_ENABLE = PropertyUtils.getString(Constants.MAIL_SMTP_STARTTLS_ENABLE);
 
@@ -70,8 +86,13 @@ public class MailUtils {
         System.setProperty("mail.mime.splitlongparameters", "false");
     }
 
+    private MailUtils() {
+        throw new IllegalStateException(MailUtils.class.getName());
+    }
+
     /**
      * send mail to receivers
+     *
      * @param receivers the receiver list
      * @param title the title
      * @param content the content
@@ -84,6 +105,7 @@ public class MailUtils {
 
     /**
      * send mail
+     *
      * @param receivers the receiver list
      * @param receiversCc cc list
      * @param title the title
@@ -149,6 +171,7 @@ public class MailUtils {
 
     /**
      * html table content
+     *
      * @param content the content
      * @param showAll if show the whole content
      * @return the html table form
@@ -159,6 +182,7 @@ public class MailUtils {
 
     /**
      * html table content
+     *
      * @param content the content
      * @return the html table form
      */
@@ -168,6 +192,7 @@ public class MailUtils {
 
     /**
      * html text content
+     *
      * @param content the content
      * @return text in html form
      */
@@ -177,9 +202,9 @@ public class MailUtils {
 
     /**
      * send mail as Excel attachment
+     *
      * @param receivers the receiver list
      * @param title the title
-     * @throws Exception
      */
     private static void attachment(Collection<String> receivers, Collection<String> receiversCc, String title, String content, String partContent) throws Exception {
         MimeMessage msg = getMimeMessage(receivers);
@@ -189,9 +214,9 @@ public class MailUtils {
 
     /**
      * get MimeMessage
+     *
      * @param receivers receivers
      * @return the MimeMessage
-     * @throws MessagingException
      */
     private static MimeMessage getMimeMessage(Collection<String> receivers) throws MessagingException {
 
@@ -223,7 +248,7 @@ public class MailUtils {
         props.setProperty(Constants.MAIL_SMTP_AUTH, Constants.STRING_TRUE);
         props.setProperty(Constants.MAIL_TRANSPORT_PROTOCOL, MAIL_PROTOCOL);
         props.setProperty(Constants.MAIL_SMTP_STARTTLS_ENABLE, STARTTLS_ENABLE);
-        if (SSL_ENABLE) {
+        if (Boolean.TRUE.equals(SSL_ENABLE)) {
             props.setProperty(Constants.MAIL_SMTP_SSL_ENABLE, "true");
             props.setProperty(Constants.MAIL_SMTP_SSL_TRUST, SSL_TRUST);
         }
@@ -241,16 +266,15 @@ public class MailUtils {
 
     /**
      * attach content
+     *
      * @param receiversCc the cc list
      * @param title the title
      * @param content the content
      * @param partContent the partContent
      * @param msg the message
-     * @throws MessagingException
-     * @throws IOException
      */
     private static void attachContent(Collection<String> receiversCc, String title, String content, String partContent, MimeMessage msg) throws MessagingException, IOException {
-        /**
+        /*
          * set receiverCc
          */
         if (CollectionUtils.isNotEmpty(receiversCc)) {
@@ -267,13 +291,13 @@ public class MailUtils {
         part1.setContent(partContent, Constants.TEXT_HTML_CHARSET_UTF_8);
         // set attach file
         MimeBodyPart part2 = new MimeBodyPart();
-        File file = new File(xlsFilePath + Constants.SINGLE_SLASH +  title + Constants.EXCEL_SUFFIX_XLS);
+        File file = new File(XLS_FILE_PATH + Constants.SINGLE_SLASH + title + Constants.EXCEL_SUFFIX_XLS);
         if (!file.getParentFile().exists()) {
             file.getParentFile().mkdirs();
         }
         // make excel file
 
-        ExcelUtils.genExcelFile(content,title,xlsFilePath);
+        ExcelUtils.genExcelFile(content, title, XLS_FILE_PATH);
 
         part2.attachFile(file);
         part2.setFileName(MimeUtility.encodeText(title + Constants.EXCEL_SUFFIX_XLS, Constants.UTF_8, "B"));
@@ -289,21 +313,21 @@ public class MailUtils {
 
     /**
      * the string object map
+     *
      * @param title the title
      * @param content the content
      * @param showType the showType
      * @param retMap the result map
      * @param email the email
      * @return the result map
-     * @throws EmailException
      */
     private static Map<String, Object> getStringObjectMap(String title, String content, String showType, Map<String, Object> retMap, HtmlEmail email) throws EmailException {
 
-        /**
+        /*
          * the subject of the message to be sent
          */
         email.setSubject(title);
-        /**
+        /*
          * to send information, you can use HTML tags in mail content because of the use of HtmlEmail
          */
         if (showType.equals(ShowType.TABLE.getDescp())) {
@@ -322,6 +346,7 @@ public class MailUtils {
 
     /**
      * file delete
+     *
      * @param file the file to delete
      */
     public static void deleteFile(File file) {
@@ -336,9 +361,9 @@ public class MailUtils {
         }
     }
 
-
     /**
      * handle exception
+     *
      * @param receivers the receiver list
      * @param retMap the result map
      * @param e the exception
@@ -347,6 +372,4 @@ public class MailUtils {
         logger.error("Send email to {} failed", receivers, e);
         retMap.put(Constants.MESSAGE, "Send email to {" + String.join(",", receivers) + "} failed，" + e.toString());
     }
-
-
 }

dolphinscheduler-alert/src/main/java/org/apache/dolphinscheduler/alert/utils/PropertyUtils.java

@@ -14,19 +14,21 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package org.apache.dolphinscheduler.alert.utils;
 
+import static org.apache.dolphinscheduler.alert.utils.Constants.ALERT_PROPERTIES_PATH;
+
 import org.apache.dolphinscheduler.common.utils.IOUtils;
 import org.apache.dolphinscheduler.common.utils.StringUtils;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.Properties;
 import java.util.regex.PatternSyntaxException;
 
-import static org.apache.dolphinscheduler.alert.utils.Constants.ALERT_PROPERTIES_PATH;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * property utils
@@ -41,8 +43,6 @@ public class PropertyUtils {
 
     private static final Properties properties = new Properties();
 
-    private static final PropertyUtils propertyUtils = new PropertyUtils();
-
     private PropertyUtils() {
         init();
     }
@@ -69,6 +69,7 @@ public class PropertyUtils {
 
     /**
      * get property value
+     *
      * @param key property name
      * @return the value
      */
@@ -104,6 +105,7 @@ public class PropertyUtils {
 
     /**
      * get int value
+     *
      * @param key the key
      * @param defaultValue the default value
      * @return the value related the key or the default value if the key not existed
@@ -124,6 +126,7 @@ public class PropertyUtils {
 
     /**
      * get property value
+     *
      * @param key property name
      * @return the boolean result value
      */
@@ -143,6 +146,7 @@ public class PropertyUtils {
 
     /**
      * get long value
+     *
      * @param key the key
      * @return if the value not existed, return -1, or will return the related value
      */
@@ -152,6 +156,7 @@ public class PropertyUtils {
 
     /**
      * get long value
+     *
      * @param key the key
      * @param defaultVal the default value
      * @return the value related the key or the default value if the key not existed
@@ -174,16 +179,17 @@ public class PropertyUtils {
 
     /**
      * get double value
+     *
      * @param key the key
      * @return if the value not existed, return -1.0, or will return the related value
      */
     public static double getDouble(String key) {
-        String val = getString(key);
         return getDouble(key, -1.0);
     }
 
     /**
      * get double value
+     *
      * @param key the key
      * @param defaultVal the default value
      * @return the value related the key or the default value if the key not existed
@@ -204,9 +210,9 @@ public class PropertyUtils {
         return defaultVal;
     }
 
-
     /**
      * get array
+     *
      * @param key property name
      * @param splitStr separator
      * @return the result array
@@ -226,6 +232,7 @@ public class PropertyUtils {
 
     /**
      * get enum
+     *
      * @param key the key
      * @param type the class type
      * @param defaultValue the default value

dolphinscheduler-alert/src/test/java/org/apache/dolphinscheduler/alert/utils/DingTalkUtilsTest.java

@@ -32,8 +32,6 @@ import org.slf4j.LoggerFactory;
 
 import java.io.IOException;
 
-import static org.junit.Assert.*;
-
 @PrepareForTest(PropertyUtils.class)
 @RunWith(PowerMockRunner.class)
 @PowerMockIgnore("javax.net.ssl.*")
@@ -97,8 +95,8 @@ public class DingTalkUtilsTest {
     @Test
     public void testProxyConfig() {
         RequestConfig rc = DingTalkUtils.getProxyConfig();
-        Assert.assertEquals(rc.getProxy().getPort(), 80);
+        Assert.assertEquals(80, rc.getProxy().getPort());
-        Assert.assertEquals(rc.getProxy().getHostName(), "proxy.com.cn");
+        Assert.assertEquals("proxy.com.cn", rc.getProxy().getHostName());
     }
 
     @Test
@@ -114,7 +112,7 @@ public class DingTalkUtilsTest {
         String msg = DingTalkUtils.textToJsonString("this is test:中文");
 
         logger.info("test support utf8, actual:" + msg);
-        logger.info("test support utf8, actual:" + DingTalkUtils.isEnableDingTalk);
+        logger.info("test support utf8, actual:" + DingTalkUtils.IS_ENABLE_DING_TALK);
         String expect = "{\"text\":{\"content\":\"this is test:中文\"},\"msgtype\":\"text\"}";
         Assert.assertEquals(expect, msg);
     }

dolphinscheduler-alert/src/test/java/org/apache/dolphinscheduler/alert/utils/ExcelUtilsTest.java

@@ -17,6 +17,10 @@
 
 package org.apache.dolphinscheduler.alert.utils;
 
+import static org.junit.Assert.assertTrue;
+
+import java.io.File;
+
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Rule;
@@ -25,8 +29,6 @@ import org.junit.rules.ExpectedException;
 import org.junit.rules.TemporaryFolder;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
-import java.io.File;
-import static org.junit.Assert.assertTrue;
 
 public class ExcelUtilsTest {
 
@@ -61,7 +63,7 @@ public class ExcelUtilsTest {
 
         //Define dest file path
         String xlsFilePath = rootPath + System.getProperty("file.separator");
-        logger.info("xlsFilePath: "+xlsFilePath);
+        logger.info("XLS_FILE_PATH: " + xlsFilePath);
 
         //Define correctContent
         String correctContent = "[{\"name\":\"ds name\",\"value\":\"ds value\"}]";

dolphinscheduler-alert/src/test/java/org/apache/dolphinscheduler/alert/utils/PropertyUtilsTest.java

@@ -41,11 +41,11 @@ public class PropertyUtilsTest {
         //Expected "EMAIL"
         String result = PropertyUtils.getString("alert.type");
         logger.info(result);
-        assertEquals(result, "EMAIL");
+        assertEquals("EMAIL", result);
 
         //Expected "xxx.xxx.test"
         result = PropertyUtils.getString("mail.server.host");
-        assertEquals(result, "xxx.xxx.test");
+        assertEquals("xxx.xxx.test", result);
 
         //If key is undefine in alert.properties, then return null
         result = PropertyUtils.getString("abc");
@@ -88,23 +88,23 @@ public class PropertyUtilsTest {
 
         //Expected 25
         long result = PropertyUtils.getLong("mail.server.port");
-        assertSame(result, 25L);
+        assertSame(25L, result);
 
         //If key is null, then return -1
         result = PropertyUtils.getLong(null);
-        assertSame(result, -1L);
+        assertSame(-1L, result);
 
         //If key is undefine in alert.properties, then return -1
         result = PropertyUtils.getLong("abc");
-        assertSame(result, -1L);
+        assertSame(-1L, result);
 
         //If key is undefine in alert.properties, and there is a defaultval, then return defaultval
         result = PropertyUtils.getLong("abc", 200);
-        assertEquals(result, 200L);
+        assertEquals(200L, result);
 
         //If the value can not parse to long ,it will log the error and return -1L
         result = PropertyUtils.getLong("test.server.testnumber");
-        assertSame(result, -1L);
+        assertSame(-1L, result);
     }
 
     /**
@@ -115,23 +115,23 @@ public class PropertyUtilsTest {
 
         //Expected 3.0
         double result = PropertyUtils.getDouble("test.server.factor");
-        assertEquals(result, 3.0, 0);
+        assertEquals(3.0, result, 0);
 
         //If key is null, then return -1.0
         result = PropertyUtils.getDouble(null);
-        assertEquals(result, -1.0, 0);
+        assertEquals(-1.0, result, 0);
 
         //If key is undefine in alert.properties, then return -1
         result = PropertyUtils.getDouble("abc");
-        assertEquals(result, -1.0, 0);
+        assertEquals(-1.0, result, 0);
 
         //If key is undefine in alert.properties, and there is a defaultval, then return defaultval
         result = PropertyUtils.getDouble("abc", 5.0);
-        assertEquals(result, 5.0, 0);
+        assertEquals(5.0, result, 0);
 
         //If the value can not parse to double ,it will log the error and return -1.0
         result = PropertyUtils.getDouble("test.server.testnumber");
-        assertEquals(result, -1.0, 0);
+        assertEquals(-1.0, result, 0);
     }
 
     /**
@@ -145,9 +145,9 @@ public class PropertyUtilsTest {
         assertEquals(result.length, 3);
 
         //Equal array values
-        assertEquals(result[0], "xxx.xxx.test1");
+        assertEquals("xxx.xxx.test1", result[0]);
-        assertEquals(result[1], "xxx.xxx.test2");
+        assertEquals("xxx.xxx.test2", result[1]);
-        assertEquals(result[2], "xxx.xxx.test3");
+        assertEquals("xxx.xxx.test3", result[2]);
 
         //If key is null, then return -1
         result = PropertyUtils.getArray(null, ",");
@@ -170,23 +170,23 @@ public class PropertyUtilsTest {
 
         //Expected 25
         int result = PropertyUtils.getInt("mail.server.port");
-        assertSame(result, 25);
+        assertSame(25, result);
 
         //If key is null, then return -1
         result = PropertyUtils.getInt(null);
-        assertSame(result, -1);
+        assertSame(-1, result);
 
         //If key is undefine in alert.properties, then return -1
         result = PropertyUtils.getInt("abc");
-        assertSame(result, -1);
+        assertSame(-1, result);
 
         //If key is undefine in alert.properties, and there is a defaultval, then return defaultval
         result = PropertyUtils.getInt("abc", 300);
-        assertEquals(result, 300);
+        assertEquals(300, result);
 
         //If the value can not parse to int ,it will log the error and return -1
         result = PropertyUtils.getInt("test.server.testnumber");
-        assertSame(result, -1);
+        assertSame(-1, result);
     }
 
     /**
@@ -197,19 +197,19 @@ public class PropertyUtilsTest {
 
         //Expected MASTER
         ZKNodeType zkNodeType = PropertyUtils.getEnum("test.server.enum1", ZKNodeType.class,ZKNodeType.WORKER);
-        assertEquals(zkNodeType, ZKNodeType.MASTER);
+        assertEquals(ZKNodeType.MASTER, zkNodeType);
 
         //Expected DEAD_SERVER
         zkNodeType = PropertyUtils.getEnum("test.server.enum2", ZKNodeType.class,ZKNodeType.WORKER);
-        assertEquals(zkNodeType, ZKNodeType.DEAD_SERVER);
+        assertEquals(ZKNodeType.DEAD_SERVER, zkNodeType);
 
         //If key is null, then return defaultval
         zkNodeType = PropertyUtils.getEnum(null, ZKNodeType.class,ZKNodeType.WORKER);
-        assertEquals(zkNodeType, ZKNodeType.WORKER);
+        assertEquals(ZKNodeType.WORKER, zkNodeType);
 
         //If the value doesn't define in enum ,it will log the error and return -1
         zkNodeType = PropertyUtils.getEnum("test.server.enum3", ZKNodeType.class,ZKNodeType.WORKER);
-        assertEquals(zkNodeType, ZKNodeType.WORKER);
+        assertEquals(ZKNodeType.WORKER, zkNodeType);
     }
 
 }