字段处理——下划线转驼峰

 把字段复制到文件里，写到另一个文件。修改代码中的文件路径

    public static void main(String[] args) throws IOException {

        readWrite();
    }



    //第一种方式：使用FileWriter和FileReader
    public static void readWrite() throws IOException {
        String dir1 = "D:\\1.txt";
        String dir2 = "D:\\2.txt";

        File readfile = new File(dir1);
        File writefile = new File(dir2);
        //创建FileReader对象，读取文件中的内容
        BufferedReader reader = new BufferedReader(new InputStreamReader(new FileInputStream(dir1),"UTF-8"));
        PrintWriter writer = new PrintWriter(new OutputStreamWriter(new FileOutputStream(dir2),"UTF-8"));
        String line = null;

        BufferedWriter writer1 = new BufferedWriter(new FileWriter(writefile));

        while((line = reader.readLine()) != null){

            String s = convertToCamel(line);
            writer.println(s);

        }

        reader.close();
        writer.close();

    }


    public static String convertToCamel(String str) {
        return str.contains("_") ? toCamelCase(str) : str.toLowerCase();
    }

    public static String toCamelCase(CharSequence name) {
        if (null == name) {
            return null;
        } else {
            String name2 = name.toString();
            if (name2.contains("_")) {
                StringBuilder sb = new StringBuilder(name2.length());
                boolean upperCase = false;

                for(int i = 0; i < name2.length(); ++i) {
                    char c = name2.charAt(i);
                    if (c == '_') {
                        upperCase = true;
                    } else if (upperCase) {
                        sb.append(Character.toUpperCase(c));
                        upperCase = false;
                    } else {
                        sb.append(Character.toLowerCase(c));
                    }
                }

                return sb.toString();
            } else {
                return name2;
            }
        }
    }