Merge branch 'v1.5.0_dev_udf' into 'v1.5.0_dev'

add udf



See merge request !19

Author: toutian

core/src/main/java/com/dtstack/flink/sql/udf/TimestampUdf.java

@@ -0,0 +1,24 @@
+package com.dtstack.flink.sql.udf;
+
+import org.apache.flink.table.functions.FunctionContext;
+import org.apache.flink.table.functions.ScalarFunction;
+
+import java.sql.Timestamp;
+
+public class TimestampUdf extends ScalarFunction {
+    @Override
+    public void open(FunctionContext context) {
+    }
+    public static Timestamp eval(String timestamp) {
+        if (timestamp.length() == 13){
+            return new Timestamp(Long.parseLong(timestamp));
+        }else if (timestamp.length() == 10){
+            return new Timestamp(Long.parseLong(timestamp)*1000);
+        } else{
+            return Timestamp.valueOf(timestamp);
+        }
+    }
+    @Override
+    public void close() {
+    }
+}