BufferedReader如何跟踪已读取的行?

我正在从一个文件中读取行,我相信一旦我读取了所有行,就会因为while循环条件而得到一个异常。

Exception in thread "main" java.lang.NullPointerException
    at liarliar.main(liarliar.java:79)

…代码…

// read the first line of the file
iNumMembers = Integer.parseInt(br.readLine().trim()); 

// read file
while ((sLine = br.readLine().trim()) != null) {

    // extract the name and value 'm'
    String[] split = sLine.split("\\s+");
    sAccuser = split[0];
    iM = Integer.parseInt(split[1]);
    saTheAccused = new String[iM];

    for (int i = 0; i < iM; i++) {
        saTheAccused[i] = br.readLine().trim();
    }

    // create member
    // initialize name and number of members being accused
    Member member = new Member();
    member.setName(sAccuser);
    member.setM(iM);
    member.setAccused(saTheAccused);

    veteranMembers.add(member);
}

内部的for循环将必须读取多行,因此如果读取文件的最后一行,则while将尝试 readLine() 这将失败,因为整个文件已经被读取。那么,怎么做呢? BufferedReader readLine() 工作以及如何安全地退出while循环?

谢谢。