首先是從一個指定的文件中讀出數據.
??? public String reader(){
??StringBuffer sb = new StringBuffer();
??try{
???? ?BufferedReader br = new BufferedReader(new FileReader("D:\\log.txt"));
???? ?String temp ;
???? ?while((temp=br.readLine())!=null){
???? ??sb.append(temp) ;
???? ??br.close();
???? ?}
???? }catch(Exception e){
???? ?e.printStackTrace() ;
???? }
???? return sb.toString();
?}

然后是把指定的字符串寫入文件中(追加形式).
public void writer(String code) {
File tofile=new File("D:\\log.txt");
????FileWriter fw=new FileWriter(tofile,true);
????BufferedWriter bw=new BufferedWriter(fw);
????PrintWriter pw=new PrintWriter(bw);
????pw.println(code);
????pw.close();
????bw.close();
????fw.close();
}