BufferedWriter不写第一行文本

Question

I am merging two text files with 123456 and abcdefg on their own lines respectively. The phenomena I am experiencing is a file that is created that is 23456abcde on the same line, so exactly as i have it typed here.

My question is

1. why is the 1 from the first file not being written
2. why are they not on their own line.
3. why is 'fg' not written. (seven lines of text data but only six writes because seven writes will output "23456" without the alphanumerical letters at all).

.

public static String mergeRecords(String in1, String in2, String out) {
    BufferedReader br1 = null;
    BufferedReader br2 = null;
    BufferedWriter bw1 = null;

    try{
        FileReader fr1 = new FileReader(in1);
        FileReader fr2 = new FileReader(in2);
        br1 = new BufferedReader(fr1);
        br2 = new BufferedReader(fr2);
        bw1 = new BufferedWriter(new FileWriter(out));
        ////File Writing
        while(!(br1.readLine()==null)||(br2.readLine()==null)){
            //alternating between the two filles
            if((f%2)==0){
                bw1.write(br1.read());
                bw1.write(br1.readLine());
                bw1.write(br1.readLine());
                bw1.write(br1.readLine());
                bw1.write(br1.readLine());
                bw1.write(br1.readLine());
            }
            else{
                bw1.write(br2.read());
                bw1.write(br2.readLine());
                bw1.write(br2.readLine());
                bw1.write(br2.readLine());
                bw1.write(br2.readLine());
                bw1.write(br2.readLine());
            }
            /////
            //File ALternator Value
            f++;
        }
        bw1.close();
    }
    catch(IOException iox){
    }
    return "'mergeRecords' not yet implemented";
}

Answer 1

The problem is that:

        while(!(br1.readLine()==null)||(br2.readLine()==null)){

consumes the first line of br1. It doesn't evaluate the second statement because the first one is already true. You never do anything with that line, so it's lost.