public class BufferedReader extends Reader {private Reader in;  构造函数需要用到的Readerprivate char cb[];   自己的char数组，它本身的read（）方法将是访问这个数组，这个数组就是缓冲区private int nChars, nextChar;     char数组位置和数量的索引

    public int read() throws IOException {synchronized (lock) {ensureOpen();for (;;) {if (nextChar >= nChars) {fill();if (nextChar >= nChars)return -1;}if (skipLF) {skipLF = false;if (cb[nextChar] == '\n') {nextChar++;continue;}}return cb[nextChar++];}}}

public class MyBufferedReader {private Reader reader;private int count;private int position;private char[] contentArray = new char[1024];private int ch;private final String LINE_SEPARATE = System.getProperty("line.separate");public MyBufferedReader(Reader reader) {this.reader = reader;}public int myReader() throws IOException {if (count == 0) {count = reader.read(contentArray);position = 0;}if (count == -1) {return -1;}count--;ch = contentArray[position];position++;return ch;}public String myReadLine() throws IOException {StringBuilder sb = new StringBuilder(256);int ch = 0;while ((ch = myReader()) != -1) {if (ch == '\r') {continue;}if ((char) ch == '\n') {return sb.toString();}sb.append((char) ch);}if (sb.length() > 0)return sb.toString();return null;}public void close() throws IOException {reader.close();}}

        try (FileWriter fileWriter = new FileWriter("buffer.txt")) {try (BufferedWriter bufferedWriter = new BufferedWriter(fileWriter)) {int count = 3;while (count != 0) {bufferedWriter.write("123456");bufferedWriter.newLine();bufferedWriter.write("abcdef");bufferedWriter.newLine();count--;}}}try (FileReader fileReader = new FileReader("buffer.txt")) {MyBufferedReader bufferedReader = new MyBufferedReader(fileReader);String line = null;while ((line = bufferedReader.myReadLine()) != null) {System.out.println(line);}}

Disconnected from the target VM, address: '127.0.0.1:26416', transport: 'socket'
123456
abcdef
123456
abcdef
123456
abcdefProcess finished with exit code 0