BufferedWriter 无法更改数据

Question

我希望你能在这方面帮助我，我正在读取一个包含多行的文件。我使用 BufferedReader 来分离数据。如果数据 1 与输入的新数据 1 不匹配，它将使用 BufferedWriter 将输入的新数据 1 替换为旧数据 1。使用以下代码，它确实更改了数据 1，但附加了其他行数据 2 和 3。我只想更改数据 1，但行保持不变。

Example(Input)

abc, 123, 456, 3345
test, t245, 442, d444
dddd, 4444, ffff, 333

public void test(String DATA1, String DATA2) throws IOException{

    br = new BufferedReader(new FileReader(file));
    while ((CurrentLine = br.readLine()) != null) {

   String[] modify = CurrentLine.split(split);
   String data1 = modify[0];
   String data2 = modify[1];
   String data3 = modify[2];
   String data4 = modify[3];

     bw = new BufferedWriter(new FileWriter(file, true));

    if (!data1.contains(DATA1)) {

    StringBuilder sb = new StringBuilder();

    while(CurrentLine != null){
        sb.append(CurrentLine.replace(data1, DATA1));
        sb.append("\n");
        CurrentLine = br.readLine();

    }

    bw.write(sb.toString());

    RESIDENTS_OLDDETAILS = new File(oldfile);
    RESIDENTS_OLDDETAILS.delete();

    RESIDENTS_NEWDETAILS = new File(newfile);
    RESIDENTS_NEWDETAILS.renameTo(old);

    br.close();
    bw.close();

Example(Output of the above code)

newabc, t245, 442, d444
newabc, t245, 442, d444
newabc, t245, 442, d444

Expected output
aaa, 123, 456, 3345
test, t245, 442, d444
dddd, 4444, ffff, 333

Edited Expected output
aaa, 123, 456, 3345
test, t245, 442, d444
dddd, 4444, ffff, 333aaa, 123, 456, 3345
test, t245, 442, d444
dddd, 4444, ffff, 333

Answer 1

看看这些修改，你会想在发现它不同后立即替换 data1，然后只需阅读其余行并将它们附加到你的 StringBuilder

public static void main(String[] args) throws Exception {
    test("aaa", "bbb");
}

public static void test(String DATA1, String DATA2) throws IOException {
    String file = "data.txt";
    String newFile = "dataNew.txt";
    
    String CurrentLine = "";
    BufferedReader br = new BufferedReader(new FileReader(file));
    while ((CurrentLine = br.readLine()) != null) {

        String[] modify = CurrentLine.split(", ");
        String data1 = modify[0];
        String data2 = modify[1];
        String data3 = modify[2];
        String data4 = modify[3];

        BufferedWriter bw = new BufferedWriter(new FileWriter(newFile, true));

        if (!data1.contains(DATA1)) {
            StringBuilder sb = new StringBuilder();
            sb.append(CurrentLine.replace(data1, DATA1));
            sb.append("\n");

            while ((CurrentLine = br.readLine()) != null) {
                sb.append(CurrentLine);
                sb.append("\n");
            }

            bw.write(sb.toString());

            File RESIDENTS_OLDDETAILS = new File(file);
            RESIDENTS_OLDDETAILS.delete();

            File RESIDENTS_NEWDETAILS = new File(newFile);
            RESIDENTS_NEWDETAILS.renameTo(RESIDENTS_OLDDETAILS);

            br.close();
            bw.close();
            break;
        }
    }
}

输入：

abc, 123, 456, 3345

test, t245, 442, d444

dddd, 4444, ffff, 333

输出：

aaa, 123, 456, 3345

test, t245, 442, d444

dddd, 4444, ffff, 333

BufferedWriter 无法更改数据

BufferedWriter can't desire change data

java

arrays

file

bufferedwriter

bufferedreader