java - CSV 保留 CRLF 同时替换 LF

Question

我有一个 csv 文件，如下(控制字符以粗体显示)

"ID","NAME","CLASS"CRLF
"1","JOHN X","A"CRLF
"2","DOELF
Y","B"CRLF
"3","OTHER S", "D"CRLF

请注意，第 3 行以 LF 而不是 CRLF 结尾。在用 Java 读取此 CSV 文件时，我得到 5 行而不是 4 行(标题行 + 3 数据行)。有没有办法可以用空格替换 LF，同时保留 CRLF(修改输入文件或更改 java 代码)。我做了很多谷歌搜索，我可以看到每个解决方案都将 LF 与 CRLF 一起替换。

谢谢

Answer 1

您可以使用分隔符为 \n 的扫描仪。使用 jlordo 的技术来消除 LF，您可以一次一行地将内容写入某个 OutputStream。这样你就永远不会在内存中保存整个 2GB 以上的文件

public static void main(String[] args) throws Exception {   
    File file = new File("C:\\Users\\Soto\\Downloads\\person.xml");
    Scanner scanner = new Scanner(new FileInputStream(file));
    String lineSeparator = System.getProperty("line.separator"); // Assuming you are on Windows, otherwise set it to \n
    scanner.useDelimiter(lineSeparator);
    ByteArrayOutputStream out = new ByteArrayOutputStream(); // would be a real outputstream, like FileOutputStream
    char LF = 0xA; 

    while (scanner.hasNext()) { // looks up to the next delimiter
        String line = scanner.next();
        line = line.replace("" + LF, "");
        out.write(line.getBytes());
        out.write(lineSeparator.getBytes());
    }

    // the OutputStream now contains the content with new lines but no LF
}

LF 是十六进制 A，参见 here .