1.使用FileRerder 類讀取文件 利用FileReader類讀取文件文本 package sad; import java.io.*; public class h {
public static void main(String[] args)throws IOException {// TODO Auto-generated method stubchar[] c = new char[500]; //創(chuàng)建一個可容納500個字符的數(shù)組try(FileReader fr = new FileReader("D:/java/test.txt");){int num = fr.read(c); //將數(shù)據(jù)讀入字符數(shù)組c內,并返回讀取的字符數(shù)String str = new String(c,0,num); //將字符數(shù)組轉換成字符串System.out.println("讀取的字符個數(shù)為:"+num+",內容如下");System.out.println(str);}
}
} 2.使用FFileReader類寫入文件 利用FileWriter類將在字符數(shù)組與字符串寫到文件里 package sad; import java.io.*; public class hh {
public static void main(String[] args) throws IOException{// TODO Auto-generated method stubFileWriter fw = new FileWriter("d:\\java\\test.txt");char[] c = {'H','E','L','L','O','\r','\n'};String str = "歡迎使用java";fw.write(c); //將字符寫入文件中fw.write(str); //將字符串寫入文件中fw.close(); //關閉流
}
} 3.使用BufferedReader類讀取文件 用緩沖字符BufferedReader類讀取文本文件 package sad; import java.io.*; public class hhh {
public static void main(String[] args)throws IOException {// TODO Auto-generated method stubString thisLine;int count = 0;try(FileReader fr = new FileReader("D:/java/test.txt");BufferedReader bfr = new BufferedReader(fr);){while((thisLine = bfr.readLine())!=null) { //每次讀取一行,直到結束count++; //計算讀取的行數(shù)System.out.println(thisLine);}System.out.println("共讀取了"+count+"行");}catch(IOException ioe) {System.out.println("錯誤"+ioe);}
}
} 4.使用BufferedWriter類寫入文件 利用緩沖區(qū)輸入輸出流進行文件賦值 package sad; import java.io.*; public class hhhh {
public static void main(String[] args)throws IOException {// TODO Auto-generated method stubString str = new String();try(BufferedReader in = new BufferedReader(new FileReader("d:/java/test.txt"));BufferedWriter out = new BufferedWriter(new FileWriter("d:/java/test1.txt"))){while((str = in.readLine())!=null) {System.out.println(str); //在顯示器上輸出out.write(str); //將讀取到的一行數(shù)據(jù)寫入到輸出流中out.newLine(); //寫入回車換行符}out.flush(); //將緩沖區(qū)中的數(shù)據(jù)全部寫入文件中}catch(IOException ioe) {System.out.println("錯誤"+ioe);}
}
