Java 建立寫入讀取

建立.txt文字檔案

import java.io.*;

public class CreateTxt{
     public static void main(String args[])throws IOException{
          File newTxt = new File("test.txt");

          if( !newTxt.exists() ){
               //在此java檔目錄下建立test.txt檔
               newTxt.createNewFile();
          }
          else{
               System.out.println("檔案已存在!");
          }
     }
}

寫入文字檔案

import java.io.*;

public class WriteTxt{
     public static void main(String args[])throws IOException{
          FileWriter dataFile = new FileWriter("test.txt");
          BufferedWriter input = new BufferedWriter(dataFile);

          //輸入Hello! World! 到test.txt檔裡
          input.write("Hello! World!");

          //寫入完關閉檔案，並儲存
          input.close();
     }
}

讀取文字檔案

import java.io.*;

public class ReadTxt{
     public static void main(String args[])throws IOException{
          FileReader dataFile = new FileReader("test.txt");
          BufferedReader output = new BufferedReader(dataFile);

          String str;
          while( (str = output.readLine()) != null ){
                 System.out.println(str);
          }

          output.close();
     }
}