IO流-字符输出流-Java

在Java的IO流中专门提供了用于字符输出的流对象PrintWriter。该对象具有自动行刷新缓冲字符输出流，特点是可以按行写出字符串，并且可通过println();方法实现自动换行。

import java.io.*;
public class LineNumberDemo3 {
	public static void main(String[] args) {
		BufferedReader br = null;
		PrintWriter pw = null;
		try {
			br = new BufferedReader(new InputStreamReader(new FileInputStream("d:/ee.txt")));
			pw = new PrintWriter("d:/eeeee.txt");
			String temp = "";
			int i = 1;
			while((temp=br.readLine())!=null) {
				System.out.println(temp);
				pw.println(i+"  "+temp);
				
				i++;
			}
			pw.flush();
		}catch(Exception e) {
			e.printStackTrace();
		}finally {
			try {
				if(br!=null) {
					br.close();
				}
			}catch(Exception e) {
				e.printStackTrace();
			}
		}
	}
}