[pick](cast)Feature cast complexttype2 json (#38632)

## Proposed changes
backport: https://github.com/apache/doris/pull/36548
Issue Number: close #xxx

<!--Describe your changes.-->

fe/fe-core/src/main/java/org/apache/doris/analysis/CastExpr.java

@@ -152,6 +152,10 @@ public class CastExpr extends Expr {
             Type from = getActualArgTypes(collectChildReturnTypes())[0];
             Type to = getActualType(type);
             NullableMode nullableMode = TYPE_NULLABLE_MODE.get(Pair.of(from, to));
+            // for complex type cast to jsonb we make ret is always nullable
+            if (from.isComplexType() && type.isJsonbType()) {
+                nullableMode = Function.NullableMode.ALWAYS_NULLABLE;
+            }
             Preconditions.checkState(nullableMode != null,
                     "cannot find nullable node for cast from " + from + " to " + to);
             fn = new Function(new FunctionName(getFnName(type)), Lists.newArrayList(e.type), type,

fe/fe-core/src/main/java/org/apache/doris/nereids/rules/expression/check/CheckCast.java

@@ -92,6 +92,9 @@ public class CheckCast implements ExpressionPatternRuleFactory {
             }
             return true;
         } else if (originalType instanceof JsonType || targetType instanceof JsonType) {
+            if (originalType.isComplexType() && !checkMapKeyIsStringLikeForJson(originalType)) {
+                return false;
+            }
             return true;
         } else {
             return checkPrimitiveType(originalType, targetType);
@@ -127,4 +130,23 @@ public class CheckCast implements ExpressionPatternRuleFactory {
         }
         return true;
     }
+
+    /**
+     * check if complexType type which contains map, make sure key is string like for json
+     *
+     * @param complexType need to check
+     * @return true if complexType can cast to json
+     */
+    public static boolean checkMapKeyIsStringLikeForJson(DataType complexType) {
+        if (complexType.isMapType()) {
+            return ((MapType) complexType).getKeyType().isStringLikeType();
+        } else if (complexType.isArrayType()) {
+            return checkMapKeyIsStringLikeForJson(((ArrayType) complexType).getItemType());
+        } else if (complexType.isStructType()) {
+            for (StructField f : ((StructType) complexType).getFields()) {
+                return checkMapKeyIsStringLikeForJson(f.getDataType());
+            }
+        }
+        return true;
+    }
 }

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/Cast.java

@@ -79,7 +79,7 @@ public class Cast extends Expression implements UnaryExpression {
             return true;
         } else if (!childDataType.isTimeLikeType() && targetType.isTimeLikeType()) {
             return true;
-        } else if (childDataType.isJsonType()) {
+        } else if (childDataType.isJsonType() || targetType.isJsonType()) {
             return true;
         } else {
             return child().nullable();