FTP Source map to MySQL create table DDL error

[baisui1981]

When use FTP as Data pipeline Source，when long type contains in FTP column metadata json description，as below：

[
  { "index": 0,   "type": "long"  },
   ]

This will lead to an error, when generate mysql table ddl

java.lang.IllegalStateException: col:id{type=-5,typeName=, columnSize=-1, decimalDigits=null} colsize can not small than 1
	at com.qlangtech.tis.plugin.datax.DataxMySQLWriter$2.convertType(DataxMySQLWriter.java:213)
	at com.qlangtech.tis.plugin.datax.DataxMySQLWriter$2.access$600(DataxMySQLWriter.java:140)
	at com.qlangtech.tis.plugin.datax.DataxMySQLWriter$2$1.getMapperType(DataxMySQLWriter.java:159)
	at com.qlangtech.tis.plugin.datax.CreateTableSqlBuilder.build(CreateTableSqlBuilder.java:89)
	at com.qlangtech.tis.plugin.datax.DataxMySQLWriter.generateCreateDDL(DataxMySQLWriter.java:258)
	at com.qlangtech.tis.datax.impl.DataXCfgGenerator.generateTabCreateDDL(DataXCfgGenerator.java:307)
	at com.qlangtech.tis.datax.impl.DataXCfgGenerator.generateDataXAndSQLDDLFile(DataXCfgGenerator.java:280)
	at com.qlangtech.tis.datax.impl.DataXCfgGenerator.access$300(DataXCfgGenerator.java:52)
	at com.qlangtech.tis.datax.impl.DataXCfgGenerator$1.generateScriptFile(DataXCfgGenerator.java:150)
	at com.qlangtech.tis.datax.impl.DataXCfgGenerator.startGenerateCfg(DataXCfgGenerator.java:242)
	at com.qlangtech.tis.datax.impl.DataXCfgGenerator.startGenerateCfg(DataXCfgGenerator.java:145)