resolve code review suggestions

Author: zyyang90

tdenginereader/doc/tdenginereader-CN.md

@@ -22,7 +22,7 @@ TDengineReader 通过 TDengine 的 JDBC driver 查询获取数据。
         "reader": {
           "name": "tdenginereader",
           "parameter": {
-            "user": "root",
+            "username": "root",
             "password": "taosdata",
             "connection": [
               {
@@ -165,24 +165,8 @@ TDengineReader 通过 TDengine 的 JDBC driver 查询获取数据。
 
 #### 4.1.1 数据特征
 
-建表语句：
-
-单行记录类似于：
-
 #### 4.1.2 机器参数
 
-* 执行DataX的机器参数为:
-    1. cpu:
-    2. mem:
-    3. net: 千兆双网卡
-    4. disc: DataX 数据不落磁盘，不统计此项
-
-* TDengine数据库机器参数为:
-    1. cpu:
-    2. mem:
-    3. net: 千兆双网卡
-    4. disc:
-
 #### 4.1.3 DataX jvm 参数
 
 	-Xms1024m -Xmx1024m -XX:+HeapDumpOnOutOfMemoryError
@@ -201,9 +185,6 @@ TDengineReader 通过 TDengine 的 JDBC driver 查询获取数据。
 
 说明：
 
-1. 这里的单表，主键类型为 bigint(20),自增。
-2. batchSize 和 通道个数，对性能影响较大。
-
 #### 4.2.4 性能测试小结
 
 1.

tdenginereader/src/main/java/com/alibaba/datax/plugin/reader/TDengineReader.java

@@ -93,7 +93,7 @@ public void init() {
             }
             if (start >= end)
                 throw DataXException.asDataXException(TDengineReaderErrorCode.ILLEGAL_VALUE,
-                        "The parameter [" + Key.BEGIN_DATETIME + "] should be less than the parameter [" + Key.END_DATETIME + "].");
+                        "The parameter " + Key.BEGIN_DATETIME + ": " + beginDatetime + " should be less than the parameter " + Key.END_DATETIME + ": " + endDatetime + ".");
 
         }
 
@@ -119,7 +119,6 @@ public List<Configuration> split(int adviceNumber) {
                 }
             }
 
-            LOG.info("Configuration: {}", configurations);
             return configurations;
         }
     }
@@ -142,15 +141,14 @@ public static class Task extends Reader.Task {
             try {
                 Class.forName("com.taosdata.jdbc.TSDBDriver");
                 Class.forName("com.taosdata.jdbc.rs.RestfulDriver");
-            } catch (ClassNotFoundException e) {
-                e.printStackTrace();
+            } catch (ClassNotFoundException ignored) {
+                LOG.warn(ignored.getMessage(), ignored);
             }
         }
 
         @Override
         public void init() {
             this.readerSliceConfig = super.getPluginJobConf();
-            LOG.info("getPluginJobConf: {}", readerSliceConfig);
 
             String user = readerSliceConfig.getString(Key.USERNAME);
             String password = readerSliceConfig.getString(Key.PASSWORD);
@@ -174,7 +172,12 @@ public void init() {
 
         @Override
         public void destroy() {
-
+            try {
+                if (conn != null)
+                    conn.close();
+            } catch (SQLException e) {
+                LOG.error(e.getMessage(), e);
+            }
         }
 
         @Override
@@ -199,22 +202,15 @@ public void startRead(RecordSender recordSender) {
                 sqlList.addAll(querySql);
             }
 
-            try (Statement stmt = conn.createStatement()) {
-                for (String sql : sqlList) {
+            for (String sql : sqlList) {
+                try (Statement stmt = conn.createStatement()) {
                     ResultSet rs = stmt.executeQuery(sql);
                     while (rs.next()) {
                         Record record = buildRecord(recordSender, rs, mandatoryEncoding);
                         recordSender.sendToWriter(record);
                     }
-                }
-            } catch (SQLException e) {
-                throw DataXException.asDataXException(TDengineReaderErrorCode.RUNTIME_EXCEPTION, e.getMessage(), e);
-            } finally {
-                try {
-                    if (conn != null)
-                        conn.close();
                 } catch (SQLException e) {
-                    e.printStackTrace();
+                    LOG.error(e.getMessage(), e);
                 }
             }
         }

tdenginewriter/src/main/java/com/alibaba/datax/plugin/writer/tdenginewriter/Constants.java

@@ -1,8 +1,6 @@
 package com.alibaba.datax.plugin.writer.tdenginewriter;
 
 public class Constants {
-    public static final String DEFAULT_USERNAME = "root";
-    public static final String DEFAULT_PASSWORD = "taosdata";
-    public static final int DEFAULT_BATCH_SIZE = 1;
+    public static final int DEFAULT_BATCH_SIZE = 1000;
     public static final boolean DEFAULT_IGNORE_TAGS_UNMATCHED = false;
 }