Java Map填充Json模版，并生成Json文件-526互联

一、准备工作

引入基础的springboot环境
引入freemark依赖

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-freemarker</artifactId>
        </dependency>

创建json模版


{

    "parameter":{
        "username":"${readerUsername}",
        "password":"${readerPassword}"
    }

}

二、创建读取模版工具类

package com.luwang.data.datax.util;

import freemarker.template.Configuration;
import freemarker.template.Template;

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

public class FreeMarkerTemplateUtils {

    public String getData(String filePath, HashMap<Object, Object> map) throws Exception {
        StringWriter writer = new StringWriter();

        //创建配置类
        Configuration cfg = new Configuration(Configuration.getVersion());
        // 设置类加载机制加载模板，这里可以参考http://freemarker.foofun.cn/pgui_config_templateloading.html的内容，这是用的第二种方法。
        cfg.setClassForTemplateLoading(this.getClass(),"/");
        // 设置字符集
        cfg.setDefaultEncoding("UTF-8");

        // 加载模板
        Template template = cfg.getTemplate(filePath);
        // 静态化内容
        template.process(map,writer);
        String content = writer.toString();

        return content;
    }
}

三、根据模版生成Json文件


    @Test
    void myDeliver3() throws Exception {
        // 该文件在resources目录下
        String filePath = "/job/JobModel.ftl";
        FreeMarkerTemplateUtils utils = new FreeMarkerTemplateUtils();

        HashMap<Object, Object> map = new HashMap<Object, Object>();
        map.put("readerUsername","root");
        map.put("readerPassword","Lqgs@2022");
        map.put("writeUsername","Lqgs@2022");
        map.put("writePassword","Lqgs@2022");
        map.put("channel","2");
        String content = utils.getData(filePath,map);
        System.out.println(content);

        FileWriter fileWriter = new FileWriter("D:\\JavaCode\\data-middle-platform\\data-datax\\datax\\job\\JobModel-2023-01.json");
        fileWriter.write(content);
        fileWriter.close();

    }