Merge pull request #1280 from tivenwang/dev

mysql select * frm aaa limit 20xxx ，limit后的字符串无法转换为数字的处理

src/main/java/com/alibaba/druid/sql/parser/Lexer.java

@@ -15,6 +15,9 @@
  */
 package com.alibaba.druid.sql.parser;
 
+import com.alibaba.druid.util.StringUtils;
+import org.apache.commons.lang.math.NumberUtils;
+
 import static com.alibaba.druid.sql.parser.CharTypes.isFirstIdentifierChar;
 import static com.alibaba.druid.sql.parser.CharTypes.isIdentifierChar;
 import static com.alibaba.druid.sql.parser.CharTypes.isWhitespace;
@@ -1147,7 +1150,11 @@ public class Lexer {
     }
 
     public BigDecimal decimalValue() {
-        return new BigDecimal(subString(mark, bufPos).toCharArray());
+        String value = subString(mark, bufPos);
+        if (!NumberUtils.isNumber(value)){
+            throw new ParserException(value+" is not a number!");
+        }
+        return new BigDecimal(value.toCharArray());
     }
 
     public static interface CommentHandler {

src/main/java/com/alibaba/druid/util/StringUtils.java

@@ -95,7 +95,7 @@ public class StringUtils {
         return a.equalsIgnoreCase(b);
     }
 
-    public static boolean isEmpty(String value) {
+    public static boolean isEmpty(CharSequence value) {
         if (value == null || value.length() == 0) {
             return true;
         }