Java简单的读写文件(包含安卓简单的文件读写)

简单的读写文件

buffer为String类型的缓冲区

fileName是文件名字

//写文件
    void writeToFile(String fileName,String buffer){
        try {
            File writeName = new File(fileName);
            writeName.createNewFile();
            try (FileWriter writer = new FileWriter(writeName);
                 BufferedWriter out = new BufferedWriter(writer)
            ) {
                out.write(buffer);
                out.flush();
            }
        } catch (IOException e) {
            System.out.println("错误");
        }
    }
    //读文件
    String readFromFile(String fileName){
        StringBuilder str=new StringBuilder();
        try(FileReader reader=new FileReader(fileName);
            BufferedReader br=new BufferedReader(reader)){
            String line;
            while((line=br.readLine())!=null){
                str.append(line).append("\n");
            }
            //buffer=str.toString();
        }catch (IOException e){
            System.out.println("错误");
        }
        return str.toString();
    }

---

下面是安卓开发简单的文件读写，文件会存放在/data/data/files/下面。

    //文件保存
    public void save(String inputText){
        FileOutputStream out=null;
        BufferedWriter writer=null;
        try {
            //“data”是文件名
            out=openFileOutput("data", Context.MODE_PRIVATE);
            writer=new BufferedWriter(new OutputStreamWriter(out));
            writer.write(inputText);
        } catch (IOException e) {
            e.printStackTrace();
        }
        finally {
            try {
                if(writer!=null)
                    writer.close();
            }catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
    //文件复读
    public String load(){
        FileInputStream inputStream=null;
        BufferedReader reader=null;
        StringBuilder content=new StringBuilder();
        try{
            //“data是文件名”
            inputStream=openFileInput("data");
            reader=new BufferedReader(new InputStreamReader(inputStream));
            String line="";
            while((line=reader.readLine())!=null){
                content.append(line);
            }
        }catch (IOException e){
            e.printStackTrace();
        }finally {
                if(reader!=null){
                    try {
                        reader.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
        }
        return content.toString();
    }

---

Android中还可以通过SharedPreferences.Editor去存储信息

//文件名为"data"
SharedPreferences.Editor editor=getSharedPreferences("data",MODE_PRIVATE).edit();
editor.putString("name","Tom");
editor.putInt("age",28);
editor.putBoolean("married",false);
editor.apply();

这样就可以存储信息了。路径是/data/data/com.项目名称/shared_prefs下面,名为"data"的文件

如果需要读取的话，那么反过来用就可以了

SharedPreferences pref=getSharedPreferences("data",MODE_PRIVATE);

//读取数据
String name=pref.getString("name","");
int age=pref.getInt("age",0);
boolean married=pref.getBoolean("married",false);

//以Log的形式输出
Log.d("MainActivity","name is "+name);
Log.d("MainActivity","age is "+age);
Log.d("MainActivity","married is "+married);

经过以上，就可以查看到刚刚存储的东西了。