java保存json格式数据，保存字符串和读取字符串

1、java保存json格式数据，保存字符串和读取字符串

import java.io.*;

class RWJson {
    public void wiite(String s, String toString) {
        BufferedWriter writer = null;
        File file = new File(s);
        //如果文件不存在，则新建一个
        if(!file.exists()){
            try {
                file.createNewFile();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        //写入
        try {
            writer = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(file,false), "UTF-8"));
            writer.write(toString);
        } catch (IOException e) {
            e.printStackTrace();
        }finally {
            try {
                if(writer != null){
                    writer.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        System.out.println("文件写入成功！");
    }

    public String readJson(String fileName) {

        BufferedReader reader = null;
        StringBuilder laststr = new StringBuilder();
        try {
            FileInputStream fileInputStream = new FileInputStream(fileName);
            InputStreamReader inputStreamReader = new InputStreamReader(fileInputStream, "UTF-8");
            reader = new BufferedReader(inputStreamReader);
            String tempString = null;
            while ((tempString = reader.readLine()) != null) {
                laststr.append(tempString);
            }
            reader.close();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (reader != null) {
                try {
                    reader.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return laststr.toString();
    }

}