如何使用缓冲写入器在文件中逐行写入?
How to write line by line in file using buffered writer?
这是我的代码,用于逐行写入文件中的文本
public class TestBufferedWriter {
public static void main(String[] args) {
// below line will be coming from user and can vary in length. It's just an example
String data = "I will write this String to File in Java";
int noOfLines = 100000;
long startTime = System.currentTimeMillis();
writeUsingBufferedWriter(data, noOfLines);
long stopTime = System.currentTimeMillis();
long elapsedTime = stopTime - startTime;
System.out.println(elapsedTime);
System.out.println("process end");
}
private static void writeUsingBufferedWriter(String data, int noOfLines) {
File file = new File("C:/testFile/BufferedWriter.txt");
FileWriter fr = null;
BufferedWriter br = null;
String dataWithNewLine=data+System.getProperty("line.separator");
try{
fr = new FileWriter(file);
br = new BufferedWriter(fr);
for(int i = 0; i<noOfLines; i++){
br.write(dataWithNewLine);
}
} catch (IOException e) {
e.printStackTrace();
}finally{
try {
br.close();
fr.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
但是它一次写入多行(使用 8192 缓冲区大小),而不是一次写入一行?不确定我在这里遗漏了什么?
您可以在每次调用 br.write(dataWithNewLine);
之后调用 br.flush()
(在循环内)。
更简洁的替代方法是使用 PrintWriter
with auto-flush:
PrintWriter pw = new PrintWriter(fr, true);
你可以用 println
写这个,就像 System.out
一样,每次都会刷新。
这也意味着您不必担心明确附加换行符。