[Java] [Freemarker] Generate Text file from FTL - example 1

Requirement
I would like to generate text file as bellows:

分行代碼  貸款代碼   客戶代碼  流水號
808      12345678   0000001   111                           
303      87654321   0000002   222                           
123      45678912   0000003   333                           
-------------------------------------------------
Number of Record(s): 0000000003

FTL File

<#assign total = 0>
<#if rows??>
分行代碼  貸款代碼   客戶代碼  流水號
<#list rows as row>
<#-- https://freemarker.apache.org/docs/ref_builtins_string.html#ref_builtin_right_pad -->
${row.branchId?right_pad(16)}${row.custLoanNumber?right_pad(11)}${row.custId?right_pad(10)}${row.ext1?right_pad(30)}
<#assign total = total + 1>
</#list>
<#else>
No Data Found!
</#if>
<#-- https://freemarker.apache.org/docs/ref_builtins_string.html#ref_builtin_left_pad -->
-------------------------------------------------
Number of Record(s): ${total?left_pad(10, "0")}

Test Case

package com.test.batch;

import com.test.batch.exception.FtlException;
import freemarker.template.Configuration;
import freemarker.template.Template;
import freemarker.template.TemplateException;
import lombok.Builder;
import lombok.Getter;
import lombok.extern.slf4j.Slf4j;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.Writer;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

@RunWith(SpringRunner.class)
@SpringBootTest
@Slf4j
public class FtlTest {

    private Configuration cfg;

    @Before
    public void init() {
        cfg = new Configuration();
        // 設定到 classpath 讀取 ftl file
        cfg.setClassForTemplateLoading(this.getClass(), "/");
    }
    @Test
    public void testBankFtl() {
        try (Writer file = new FileWriter(new File("C:/ftl_bank.txt"));) {
            Template template = cfg.getTemplate("ftl/bank.ftl");

            Map<String, Object> data = new HashMap<>();

            List<Row> rows = new ArrayList<Row>();
            rows.add(Row.builder().branchId("808").custLoanNumber("12345678").custId("0000001").ext1("111").build());
            rows.add(Row.builder().branchId("303").custLoanNumber("87654321").custId("0000002").ext1("222").build());
            rows.add(Row.builder().branchId("123").custLoanNumber("45678912").custId("0000003").ext1("333").build());

            data.put("rows", rows);

            template.process(data, file);
        } catch (IOException | TemplateException e) {
            throw new FtlException("fail to generate file from ftl file : " + e.getMessage(), e);
        }
    }

    @Getter
    @Builder
    public static class Row {
        private String branchId;
        private String custLoanNumber;
        private String custId;
        private String ext1;
    }

}