在freemarker页面获取长类型值的逗号

long longValue = 1234567890L;
String longString = String.valueOf(longValue);
String formattedLongString = "";
for (int i = 0; i< longString.length(); i++) {
    formattedLongString = longString.charAt(i) + formattedLongString;
    if (i > 0 && (longString.length() - i) % 3 == 0) {
        formattedLongString = "," + formattedLongString;
    }
}

<#-- 假设将转换后的字符串赋值给变量formattedLongValue -->
${formattedLongValue}

import freemarker.template.Configuration;
import freemarker.template.Template;
import freemarker.template.TemplateException;
import freemarker.template.TemplateModelException;

import java.io.IOException;
import java.io.StringWriter;
import java.util.HashMap;
import java.util.Map;

public class Main {
    public static void main(String[] args) throws IOException, TemplateException {
        Configuration configuration = new Configuration(Configuration.VERSION_2_3_31);
        configuration.setClassForTemplateLoading(Main.class, "/");
        Template template = configuration.getTemplate("template.ftl");

        Map<String, Object> dataModel = new HashMap<>();
        dataModel.put("addCommas", new AddCommasMethod());
        dataModel.put("longValue", 1234567890L);

        StringWriter stringWriter = new StringWriter();
        template.process(dataModel, stringWriter);
        System.out.println(stringWriter.toString());
    }

    public static class AddCommasMethod implements freemarker.template.TemplateMethodModelEx {
        @Override
        public Object exec(List arguments) throws TemplateModelException {
            if (arguments.size() != 1) {
                throw new TemplateModelException("Wrong number of arguments");
            }
            if (!(arguments.get(0) instanceof Number)) {
                throw new TemplateModelException("Argument must be a number");
            }
            Number number = (Number) arguments.get(0);
            String numberString = String.valueOf(number);
            StringBuilder formattedNumberString = new StringBuilder();
            for (int i = 0; i< numberString.length(); i++) {
                formattedNumberString.insert(0, numberString.charAt(i));
                if (i > 0 && (numberString.length() - i) % 3 == 0) {
                    formattedNumberString.insert(0, ",");
                }
            }
            return formattedNumberString.toString();
        }
    }
}

<#-- 假设将长类型值赋值给变量longValue -->
${addCommas(longValue)}