DataX 是阿里云开源离线同步工具，致力于实现包括关系型数据库(MySQL、Oracle等)、HDFS、Hive、MaxCompute(原ODPS)、HBase、FTP等各种异构数据源之间稳定高效的数据同步功能。

Datax 的数据转换支持 UserDefined Function

官方的使用说明如下：

dx_groovy

• 参数。
  • 第一个参数： groovy code
  • 第二个参数（列表或者为空）：extraPackage
• 备注：
  • dx_groovy只能调用一次。不能多次调用。
  • groovy code中支持java.lang, java.util的包，可直接引用的对象有record，以及element下的各种column（BoolColumn.class,BytesColumn.class,DateColumn.class,DoubleColumn.class,LongColumn.class,StringColumn.class）。不支持其他包，如果用户有需要用到其他包，可设置extraPackage，注意extraPackage不支持第三方jar包。
  • groovy code中，返回更新过的Record（比如record.setColumn(columnIndex, new StringColumn(newValue));），或者null。返回null表示过滤此行。
  • 用户可以直接调用静态的Util方式（GroovyTransformerStaticUtil），目前GroovyTransformerStaticUtil的方法列表 (按需补充)：
• 举例:

groovy 实现的subStr:
        String code = "Column column = record.getColumn(1);\n" +
                " String oriValue = column.asString();\n" +
                " String newValue = oriValue.substring(0, 3);\n" +
                " record.setColumn(1, new StringColumn(newValue));\n" +
                " return record;";
        dx_groovy(record);

groovy 实现的Replace
String code2 = "Column column = record.getColumn(1);\n" +
                " String oriValue = column.asString();\n" +
                " String newValue = \"****\" + oriValue.substring(3, oriValue.length());\n" +
                " record.setColumn(1, new StringColumn(newValue));\n" +
                " return record;";

groovy 实现的Pad
String code3 = "Column column = record.getColumn(1);\n" +
                " String oriValue = column.asString();\n" +
                " String padString = \"12345\";\n" +
                " String finalPad = \"\";\n" +
                " int NeedLength = 8 - oriValue.length();\n" +
                "        while (NeedLength > 0) {\n" +
                "\n" +
                "            if (NeedLength >= padString.length()) {\n" +
                "                finalPad += padString;\n" +
                "                NeedLength -= padString.length();\n" +
                "            } else {\n" +
                "                finalPad += padString.substring(0, NeedLength);\n" +
                "                NeedLength = 0;\n" +
                "            }\n" +
                "        }\n" +
                " String newValue= finalPad + oriValue;\n" +
                " record.setColumn(1, new StringColumn(newValue));\n" +
                " return record;";

• 以下是我自己实现的字符串替换 dx_groovy 函数
  {
  "job": {
  "content": [
  {
  "reader": {
  "name": "mysqlreader",
  "parameter": {
  "column": ["user_role_id","username","ROLE"],
  "connection": [
  {
  "jdbcUrl": ["jdbc:mysql://10.1.18.155:3306/saiku_test"],
  "table": ["user_roles_copy"]
  }
  ],
  "password": "123456",
  "username": "root",
  "where": ""
  }
  },
  "writer": {
  "name": "mysqlwriter",
  "parameter": {
  "column": ["user_role_id","username","ROLE"],
  "connection": [
  {
  "jdbcUrl": "jdbc:mysql://10.1.18.155:3306/saiku_test",
  "table": ["user_roles_trans"]
  }
  ],
  "password": "123456",
  "preSql": [],
  "session": [],
  "username": "root",
  "writeMode": "insert"
  }
  },
  "transformer": [
  {
  "name": "dx_filter",
  "parameter":
  {
  "columnIndex":1,
  "paras":["=","null"]
  }
  },{
  "name": "dx_groovy",
  "parameter":
  {
  "code": "Column column = record.getColumn(2);\nString oriValue = column.asString();\nString sourceString = "ROLE_ADMIN";\nString changeString = "replaceTest";\nif (oriValue.equals(sourceString)){record.setColumn(2, new StringColumn(changeString));\nreturn record;}\nreturn record;",
  "extraPackage":[]
  }
  }
  ]
  }
  ],
  "setting": {
  "speed": {
  "channel": "1"
  }
  }
  }
  }