Question

如何在JAVA程序显示时每行添加行号

使用RandomAccessFile类及方法,把程序本身显示两次,一次直接显示,一次给每一行添加行号会显示.

Answer 1

大概就是这样啦，换成你自己的文件名就行了

import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.util.ArrayList;

public class ShowSourceCode {

public static void main(String[] args) throws FileNotFoundException, IOException{

RandomAccessFile file = new RandomAccessFile("Add.java", "r");
String tmp;

while((tmp = file.readLine()) != null){
System.out.println(tmp);
}

file.seek(0);

int lineNum = 1;
while((tmp = file.readLine()) != null){
System.out.println(lineNum + ": " + tmp);
lineNum++;
}
}

}