java 保存和读取本地json文件

Posted 2021-01-12 星朝

保存数据到本地文件

private void saveDataToFile(String fileName,String data) {
        BufferedWriter writer = null;
        File file = new File("d:\"+ fileName + ".json");
        //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(data);
        } 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！");
    }

取数据

private String getDatafromFile(String fileName) {
      
     String Path="d:\" + fileName+ ".json";
        BufferedReader reader = null;
      String laststr = "";
        try {
          FileInputStream fileInputStream = new FileInputStream(Path);
           InputStreamReader inputStreamReader = new InputStreamReader(fileInputStream, "UTF-8");
            reader = new BufferedReader(inputStreamReader);
           String tempString = null;
         while ((tempString = reader.readLine()) != null) {
              laststr += tempString;
          }
           reader.close();
     } catch (IOException e) {
         e.printStackTrace();
        } finally {
           if (reader != null) {
               try {
                 reader.close();
             } catch (IOException e) {
                 e.printStackTrace();
                }
           }
       }
       return laststr;
   }