自定义BufferedReader

import java.io.FileReader;
import java.io.IOException;

class MyBufferedReader {

private FileReader r;

MyBufferedReader(FileReader r) {
this.r = r;
}

// 按行读
public String myReadLine() throws IOException {
StringBuilder sb = new StringBuilder();
int ch = 0;
while ((ch = r.read()) != -1) {
if (ch == '\r')
continue;
if (ch == '\n')
return sb.toString();
sb.append((char) ch);
}
if(sb.length()!=0)     //将最后一行返回
return sb.toString();
return null;
}

//关闭
public void myClose() throws IOException {
r.close();
}
}