Java進行文件輸出時,有時候想直接向已有文件末尾追加字符,而不是從頭開始寫,能夠採用如下三種方式實現:java
1 package test; 2 import java.io.File; 3 import java.io.FileOutputStream; 4 import java.io.FileWriter; 5 import java.io.IOException; 6 import java.io.PrintWriter; 7 import java.io.RandomAccessFile; 8 9 public class FileRW { 10 public static void main(String[] a) { 11 //方式一: 12 try { 13 FileOutputStream fos = new FileOutputStream (new File("d:\\abc.txt"),true ) ; 14 String str = "ABC \n" ; //字符串末尾須要換行符 15 fos.write(str.getBytes()) ; 16 fos.close (); 17 } catch (IOException e) { 18 e.printStackTrace(); 19 } 20 21 //方式二: 22 try { 23 FileWriter fw = new FileWriter("d:\\abc.txt",true); 24 PrintWriter pw=new PrintWriter(fw); 25 pw.println("append content"); //字符串末尾不須要換行符 26 pw.close () ; 27 fw.close () ; 28 } catch (IOException e) { 29 e.printStackTrace(); 30 } 31 32 //方式三: 33 try { 34 RandomAccessFile rf=new RandomAccessFile("d:\\abc.txt","rw"); 35 rf.seek(rf.length()); //將指針移動到文件末尾 36 rf.writeBytes("Append a line again!\n"); //字符串末尾須要換行符 37 rf.close();//關閉文件流 38 }catch (IOException e){ 39 e.printStackTrace(); 40 } 41 42 43 } 44 45 }