MaxCompute:Develop Java UDFs with IntelliJ IDEA

Procedure

1. Write a Java UDF.

   1. In the Project tool window, right-click the module's source directory, src > main > java, and select New > MaxCompute Java.

      

   2. In the Create new MaxCompute java class dialog box, select UDF, enter a name in the Name field, and then press Enter. For example, name the Java class Lower.

      

      Name is the name of the MaxCompute Java class. If you have not created a package, you can enter packagename.classname to automatically generate a package.

   3. In the code editor, enter the following code.

      The UDF code example is as follows.

      package <packagename>;
      import com.aliyun.odps.udf.UDF;
      public final class Lower extends UDF {
          public String evaluate(String s) {
              if (s == null) { 
                 return null; 
              }
                 return s.toLowerCase();
          }
      }

2. Debug the UDF to verify that it runs correctly.

   1. In the java directory, right-click the Java file and select Run.

   2. In the Run/Debug Configurations dialog box, configure the parameters.

      

      • MaxCompute project: The MaxCompute project where the UDF runs. For a local run, select local.

      • MaxCompute table: The name of the MaxCompute table used by the UDF.

      • Table columns: The column information of the MaxCompute table used by the UDF.

   3. Click OK. The following figure shows the result.

3. Register the MaxCompute UDF.

   1. Right-click the UDF Java file and select Deploy to server....

   2. In the Package a jar, submit resource and register function dialog box, configure the following parameters.

      

      • MaxCompute project: The project where the UDF will be registered. You can typically keep the default value.

      • Resource file: The path to the dependent resource file. You can keep the default value.

      • Resource name: The name of the dependent resource. You can keep the default value.

      • Function name: The registration name for the function. This name is used to call the UDF in SQL statements. For example, Lower_test.

   3. Click OK to complete the UDF registration.

4. Call the UDF.

   In the Project Explorer pane on the left, right-click the target MaxCompute project, select Open in Console, enter the SQL statement to call the UDF in the console, and press Enter to run it.

   select Lower_test('ALIYUN');

   This result confirms that the Lower_test Java UDF is ready to use.