一、读取txt文件。

1、步骤 : 

①、创建文件句柄

File file = new File(filePath);

②、将文件内容读取到内存中

new FileInputStream(file)

③、封装数据 InputStreamReader

InputStreamReader read = new InputStreamReader(new FileInputStream(file), encoding)

④、读取数据

BufferedReader bufferedReader = new BufferedReader(read);

　　每行数据

bufferedReader.readLine()

2、场景 ： txt文件内容 ：

123

456

...

读取每行内容, 并将每行内容用 , 拼接成  123,456

public class ReadTxt {        public static void main(String[] args) {        String filePath = "/Users/xupengwei/Downloads/test.txt";        readTxtFile(filePath );    }    public static void readTxtFile(String filePath) {        try {            String encoding = "GBK";            File file = new File(filePath);            if (file.isFile() && file.exists()) { // 判断文件是否存在                InputStreamReader read = new InputStreamReader(new FileInputStream(file), encoding);// 考虑到编码格式                BufferedReader bufferedReader = new BufferedReader(read);                String lineTxt = null;                StringBuffer sb = new StringBuffer();                while ((lineTxt = bufferedReader.readLine()) != null) {                    sb.append(lineTxt);                    sb.append(",");                }                System.out.println(sb.toString());                read.close();            } else {                System.out.println("找不到指定的文件");            }        } catch (Exception e) {            System.out.println("读取文件内容出错");            e.printStackTrace();        }    }}

二、拓展...

场景 : 正则匹配