用java实现在txt文本中写数据和读数据的方法

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
public class Test {
	public static void main(String[] args) {
  File file = null;
  FileWriter fw = null;
  file = new File("F:\\JMeterRes\\Data\\test123.txt");
  try {
   if (!file.exists()) {
    file.createNewFile();
   }
   fw = new FileWriter(file);
   for(int i = 1;i <=3000;i++){
   fw.write("abcdefgabcdefg"+i+",");//向文件中写内容
   fw.write("sssssssssssssss"+i+",\r\n");
   fw.flush();
   }
   System.out.println("写数据成功！");
  } catch (IOException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }finally{
   if(fw != null){
    try {
     fw.close();
    } catch (IOException e) {
     // TODO Auto-generated catch block
     e.printStackTrace();
    }
   }
  }
 }
}

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
 
public class ReadFiledata {
 public static String txt2String(File file){
  StringBuilder result = new StringBuilder();
  try{
   BufferedReader br = new BufferedReader(new FileReader(file));//构造一个BufferedReader类来读取文件
   String s = null;
   while((s = br.readLine())!=null){//使用readLine方法，一次读一行
    result.append(System.lineSeparator()+s);
   }
   br.close(); 
  }catch(Exception e){
   e.printStackTrace();
  }
  return result.toString();
 }
 
 public static void main(String[] args){
  File file = new File("F:/JMeterRes/Data/test123.txt");
  System.out.println(txt2String(file));
 }
}