Fastjson 实现类导出json文件

Posted 2021-05-29 zolty

0.背景

利用fastjson实现 java类导出json文件

依赖：

<!-- 阿里JSON解析器 -->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>${fastjson.version}</version>
</dependency>

1.定义类

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.nio.charset.StandardCharsets;
import java.util.Map;

public class MqttJson {
    private int[] dev_ids;
    private String msg_type;
    private Map<String,Integer> control_command;

    public int[] getDev_ids() {
        return dev_ids;
    }

    public void setDev_ids(int[] dev_ids) {
        this.dev_ids = dev_ids;
    }

    public String getMsg_type() {
        return msg_type;
    }

    public void setMsg_type(String msg_type) {
        this.msg_type = msg_type;
    }

    public Map<String, Integer> getControl_command() {
        return control_command;
    }

    public void setControl_command(Map<String, Integer> control_command) {
        this.control_command = control_command;
    }

    //导出函数
    public static void save(String filename,String json) throws IOException {
        OutputStreamWriter osw=new OutputStreamWriter(new FileOutputStream(filename), StandardCharsets.UTF_8);
        osw.write(json);
        osw.flush();
        osw.close();
    }
}

2.赋值以及转化导出

public void class2json()throws IOException {
    MqttJson mqttJson = new MqttJson();
    mqttJson.setDev_ids(String2int(ids));
    mqttJson.setMsg_type("CONTROLCOMMAND");
    Map<String, Integer> contol_comand = new HashMap<String, Integer>(){
        {
            put("stack_flag", 1);
            put("record_log_flag", 1);
        }
    };
    mqttJson.setControl_command(contol_comand);
    String json= JSON.toJSONString(mqttJson);
    mqttJson.save("D://CONTROL_COMMAND.json",json);
}

3.JSON效果

{
    "control_command":{"record_log_flag":1,"stack_flag":1},
    "dev_ids":[1,2,3,4,5],
    "msg_type":"CONTROLCOMMAND"
}