java.io（基本操作方式）

in

public static String readText(String fileName){        StringBuilder stringBuilder=new StringBuilder();        try {            BufferedReader in = new BufferedReader(                    new FileReader(                            new File(fileName).getAbsoluteFile()));            try {                String s;                while ((s = in.readLine()) != null) {                    stringBuilder.append(s);                    stringBuilder.append('\n');                }            } finally {                in.close();            }        } catch (IOException e) {            throw new RuntimeException(e);        }        return stringBuilder.toString();    }

out

public static void writeText(String pathName,String text){        File file=new File(pathName);        try{            PrintWriter out=new PrintWriter(file.getAbsoluteFile());            try {                out.print(text);            }finally {                out.close();                System.out.println(pathName+" creating");            }        } catch (IOException e){            throw new RuntimeException(e);        }    }

优先使用Reader以防格式错误，老式的stream处理８位数据，新的可解决ｕｎｉｃｏｄｅ编码。