1.创建实体对像json

import com.alibaba.fastjson.annotation.JSONField;import java.util.Date;public class Student {    private int id;    private String name;    @JSONField(format = "yyyy-MM-dd hh:mm:ss")    private Date birthDay;    private boolean sex;    public int getId() {        return id;    }    public void setId(int id) {        this.id = id;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public Date getBirthDay() {        return birthDay;    }    public void setBirthDay(Date birthDay) {        this.birthDay = birthDay;    }    public boolean isSex() {        return sex;    }    public void setSex(boolean sex) {        this.sex = sex;    }}

2.使用fastjson生成 json字符串并写入文件

import com.alibaba.fastjson.JSONObject;import  entities.Student;import java.nio.charset.StandardCharsets;import java.nio.file.Files;import java.nio.file.Path;import java.nio.file.Paths;import java.nio.file.StandardOpenOption;import java.util.Date;

private Path getConfPath() {        String appPath = System.getProperty("user.dir");        Path ConfPath = Paths.get(appPath, "app.conf");        return ConfPath;    }    private String read() {        Path ConfPath = getConfPath();        if (!Files.exists(ConfPath)) {            write();        }        byte[] bytes = new byte[]{};        try {            bytes = Files.readAllBytes(ConfPath);        } catch (Exception e) {            logger.error("读取文件失败{}", ConfPath.toAbsolutePath(), e);        }        String jsonString = new String(bytes);        return jsonString;    }    private void write() {        Student stu = new Student();        stu.setId(1);        stu.setSex(false);        stu.setBirthDay(new Date());        stu.setName("jack");        String jsonString = JSONObject.toJSONString(stu,true);        Path ConfPath = getConfPath();        try {            if (!Files.exists(ConfPath))                Files.createFile(ConfPath);        } catch (Exception e) {            logger.error("创建文件失败{}", ConfPath.toAbsolutePath(), e);        }        try {            Files.write(ConfPath, jsonString.getBytes(StandardCharsets.UTF_8), StandardOpenOption.CREATE);        } catch (Exception ex) {            logger.error("写入配置文件失败{}", ConfPath.toAbsolutePath(), ex);        }    }