java读取文本文件，stringBuilder换行输出

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;


public class Read_1 {
   static StringBuilder sb = new StringBuilder();
	static String str;
   public static void main(String[] args) {
	   BufferedReader br;
	try {
		br = new BufferedReader(new FileReader("test.txt"));
		 String data = br.readLine();//一次读入一行，直到读入null为文件结束
		 while ((str = br.readLine())!= null) // 判断最后一行不存在，为空结束循环
		 {
		// System.out.println(str);//原样输出读到的内容
		  sb.append(str);
		  sb.append("\r\n");
		 }
		 br.close();
		  System.out.println(sb.toString());
	} catch (FileNotFoundException e) {
		// TODO Auto-generated catch block
		e.printStackTrace();
	} catch (IOException e) {
		// TODO Auto-generated catch block
		e.printStackTrace();
	}
	   
}
	
}//Read_1

结果：