如何在文本文件中追加字符串？！

1.

可以先把文件里面的东西读出来,放在StringBuffer里面,然后在追加
如: File f=new File("D:/aa.txt");
try
{
InputStream a = new FileInputStream(f);
BufferedReader ins = new BufferedReader(new InputStreamReader(a));
StringBuffer buffer = new StringBuffer();
String line = "";
while ((line = ins.readLine()) != null)
{
buffer.append(line);
System.out.println(buffer.toString());
}
buffer.append("这是后来加的");

FileOutputStream out = new FileOutputStream(f);
out.write(buffer.toString().getBytes());
}
catch(Exception e)
{
e.printStackTrace();
} 

2.

File f=new File("D:/aa.txt");
try
{
FileOutputStream out = new FileOutputStream(f,true);
out.write("aaaaaa".getBytes());
}
catch(Exception e)
{
e.printStackTrace();
}

FileOutputStream接收两个参数,后面个boolean决定是追加还是覆盖
3.

PrintWriter out = new PrintWriter(new BufferedWriter(
					new FileWriter(rcFile, true)), true);
out.println(sb.toString());
第一个true代表append，第二个代表autoflush