021.5 IO stream - character stream

###############Basic function
write

FileWriter fw = new FileWriter("xxx.txt");
fw.write("哈喽");
fw.close();

read

FileReader fr = new FileReader("xxx.txt");
int ch = 0;
while((ch = fr.read()) != -1){
    System.out.println((char)ch);
}
fr.close();

##############Character stream buffer
write

private static void writeTextByBuffered() throws IOException
{
    FileWriter fw = new FileWriter("char_xxx.txt");
    BufferedWriter bw = new BufferedWriter(fw);
    bw.write("小红");
    bw.newLine();
    bw.write( "Xiaohua, Xiaohua" );
    bw.flush();
    bw.close();
}

read

private static void writeTextByBuffered() throws IOException
{
    FileWriter fw = new FileWriter("char_xxx.txt");
    BufferedWriter bw = new BufferedWriter(fw);
    bw.write("小红");
    bw.newLine();
    bw.write( "Xiaohua, Xiaohua" );
    bw.flush();
    bw.close();
}

Read keyboard input information, Scanner=stream+regular expression. The method is to read data according to certain rules
BufferedReader bufr = new BufferedReader(new InputStreamReader(System.in);
bufr.readLine();