java 保存和读取本地文件

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");
        //若是文件不存在，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;
	}