用Java I0 api将SomeData.txt其中的所有数据读出，计算出每一行的后4列数据的平均值，存放到新文件AvgSomeData.txt文件中

Posted 2021-07-18 Pistachiout

查看文本文件SomeData.txt中的数据并分析其格式，用Java I0 api将其中的所有数据读出，计算出每一行的后4列数据的平均值，存放到新文件AvgSomeData.txt文件中，存放时每一行前面要加上行号（行号占3位，右对齐），平均值放到行末并左对齐。

import java.util.*;
import java.io.*;
public class FIleStream {
	public static void main(String[] args) {
		
		FileReader inReader;
		FileWriter outWriter;
		try{
			inReader=new FileReader("D:\\\\Documents\\\\SomeData.txt");
			outWriter=new FileWriter("D:\\\\Documents\\\\SomeData2.txt");
			//inReader.
		}
		catch (IOException e)
		{
			System.out.println("File can't be found or File creates error.");
			return;
		}

		
		BufferedReader in=new  BufferedReader(inReader);//???????????????????????
		BufferedWriter out=new BufferedWriter(outWriter);//????????????????????????
		String str;
		int lineNo=0;
		
		//inStream.read
		
		try{
			
			while ((str=in.readLine())!=null)
			{
				System.out.print(str);
				String[] splits=str.split("\\t");
				System.out.println("  "+(int)(Double.parseDouble(splits[3])+Double.parseDouble(splits[4])+Double.parseDouble(splits[5])+Double.parseDouble(splits[6]))/4);
				out.write(String.format("%1$03d", lineNo++)+"  "+str+"\\t"+(int)(Double.parseDouble(splits[3])+Double.parseDouble(splits[4])+Double.parseDouble(splits[5])+Double.parseDouble(splits[6]))/4+"\\r\\n");
			}
			in.close();
			out.close();
			inReader.close();
			outWriter.close();
		}catch(IOException e)
		{
			System.out.println("\\nIO Errors.");
			return;
		}
		System.out.println("\\n\\n\\nDone!");
		

	}
}